WO2022184892A1

WO2022184892A1 - Process for the preparation of a mixed metal oxide

Info

Publication number: WO2022184892A1
Application number: PCT/EP2022/055548
Authority: WO
Inventors: Marcelo Daniel Kaufman Rechulski; Sabine Borchers; Juergen Amann
Original assignee: Basf Se
Priority date: 2021-03-04
Filing date: 2022-03-04
Publication date: 2022-09-09

Abstract

The present invention relates to a process for the preparation of a mixed metal oxide comprising one or more transition metals T, one or more divalent elements M, one or more trivalent elements N, and O, the process comprising (1) preparing a mixture comprising a solvent system, a layered double hydroxide compound, and one or more sources of one or more transition metals T, wherein the layered double hydroxide compound comprises one or more divalent elements M and one or more trivalent elements N, and wherein the pH of the solvent system is comprised in the range of from 2 to 9; (2) heating the mixture prepared in (1); (3) adjusting the pH of the mixture obtained in (2) to a pH comprised in the range of from 5 to 12; (4) optionally aging the mixture obtained in (3); (5) isolating the solids from the mixture obtained in (3) or (4); (6) optionally washing the solids obtained in (5); (7) drying the solids obtained in (5) or (6); and (8) calcining the solids obtained in (5), (6), or (7). The present invention also relates to the mixed metal oxide, to the method for reforming one or more hydrocarbons and to the use of the mixed metal oxide.

Description

Process for the Preparation of a Mixed Metal Oxide

TECHNICAL FIELD

The present invention relates to a process for the preparation of a mixed metal oxide, as well as the mixed metal oxide. The present invention furthermore relates to the method for reforming one or more hydrocarbons, as well as the use of the mixed metal oxide as a catalytically active material.

INTRODUCTION

Reforming of hydrocarbons to a synthesis gas is a known catalytic reaction, in which Ni- or Co containing oxide-based catalysts are used. In general, cost-effective solutions have great eco nomic potential due to the pressure on cost minimization. Thus, the production costs for reform ing of hydrocarbons to a synthesis gas, which particularly comprises hydrogen and carbon monoxide, may be reduced by using a more active and selective mixed oxide as heterogeneous oxidic reforming catalyst. A positive effect on the production costs and catalyst efficiency can indirectly be achieved by the stability and longevity of the catalyst.

WO 2013/068905 A1 relates to a process for producing a reforming catalyst and reforming of methane. Further, a catalyst for the reforming of hydrocarbon-comprising compounds and C0₂ to synthesis gas is disclosed. The catalyst is defined as comprising at least nickel-magnesium mixed oxide and magnesium spinel, and optionally aluminum oxide hydroxide, wherein said components are specified by their respective average crystallite size and their molar content, and wherein the catalyst is defined by specific XRD characteristics. In particular, table 7 shows characteristics for example 1 wherein a magnesium nickel mixed oxide having the empirical formula Nio_.5Mgo_.5O would be comprised in the sample. Said example was repeated and it is disclosed herein as Comparative Example 1. It has been determined that a magnesium nickel mixed oxide having the empirical formula Nio_.52Mgo_.48O is obtained. Thus, the values for magne sium and nickel have been rounded in the prior art.

ON 107890870 A, US 2018/0141028 A1 , US 2010/0213417 A1 , ON 108704647 A, ON 106512999 A, US 2012/0190539 A1 , JP 2017/029970 A, and EP 2335824 A1 respectively re late to a reforming catalyst and to a method for its production based on the precipitation of ni trate salts as precursor compounds.

The process for preparation of a mixed oxide serving as a catalytically active species especially for the reforming of hydrocarbons to a synthesis gas is currently either done by precipitation, e. g. from an aqueous solution, or by mixing of the starting materials as solids, i.e. the solid mix ing route. Both state-of-the-art routes involve the use of the corresponding water-soluble metal salts as starting materials. DETAILED DESCRIPTION

Thus, it was an object to provide a process for preparing a novel molding, in particular to pro vide a process resulting in a molding having advantageous properties, preferably when used as a catalyst or catalyst component, specifically in a reforming process. Further, it was an object of the present invention to provide a novel molding suitable as catalyst for reforming one or more hydrocarbons, preferably for reforming methane, to a synthesis gas comprising hydrogen and carbon monoxide, which shows a very good longevity and shows an improved catalytic perfor mance, in particular with regard to the conversion of one or more of methane and carbon diox ide. It was a further object of the present invention to provide an improved process for reforming one or more hydrocarbons, preferably for reforming methane, to a synthesis gas comprising hydrogen and carbon monoxide, exhibiting a superior catalytic performance in particular as concerns the conversion of one or more of methane and carbon dioxide.

According to the present invention it has surprisingly been found that according to the inventive method, mixed metal oxides may be obtained from the loading of layered double hydroxide compounds with transition metals, wherein the transition metal cations may be homogeneously dispersed within the existing architecture of the layered double hydroxide for affording inventive transition metal loaded layered double hydroxides displaying a homogeneous distribution of the transition metals between the layers of the existing architecture.

This finding is highly unexpected since layered double hydroxides typically display framework architectures which are positively charged, in particular at low pH levels, and thus do not allow for the dispersion of positively charged transition metal cations therein. On the other hand, at higher pH levels, transition metal cations are often subject to precipitation, such that they may not be dispersed within the layered double hydroxide architecture. As a result, the conventional methods employed for the loading of such architectures in solvent systems normally affords a precipitation of the transition metal species on the outer surface of the layered double hydroxide compounds in question. As a result, conventional loading methods in solvent systems only allow for a limited control of the deposition of the transition metal species, which are primarily formed on the outer surface of the layered double hydroxide compounds. In particular, even at lower loadings of the transition metal, transition metal-rich mixed oxide phases are formed, whereas the incorporation of the transition metal within the layered double hydroxide architecture accord ing to the inventive method effectively limits the formation of transition metal-rich mixed oxide phases, in particular at low transition metal loadings.

Thus, it has surprisingly been found that the specific control of the pH in the inventive method allows for a circumvention of the aforementioned disadvantages encountered in the convention al methods of loading layered double hydroxide compounds with transition metals. As a result, the inventive method allows for an unprecedented control of the transition metal species which are formed during the loading process due to their substantially homogeneous dispersion within the defined architecture of a layered double hydroxide framework, and thus in turn to highly ho mogeneous and well-defined transition metal species which are comprised in the inventive ma terials. The inventive materials therefore display well-defined chemical and physical properties, as a result of which they are predestined for catalytic applications in which such properties are highly desirable, such as to provide a high control over the catalytic conversion processes in terms of catalytic selectivity.

Therefore, the present invention relates to a process a process for the preparation of a mixed metal oxide comprising one or more transition metals T, one or more divalent elements M, one or more trivalent elements N, and O, the process comprising

(1) preparing a mixture comprising a solvent system, a layered double hydroxide compound, and one or more sources of one or more transition metals T, wherein the layered double hy droxide compound comprises one or more divalent elements M and one or more trivalent ele ments N, and wherein the pH of the solvent system is comprised in the range of from 2 to 9;

(2) heating the mixture prepared in (1), preferably to a temperature comprised in the range of from 30 to 90 °C;

(3) adjusting the pH of the mixture obtained in (2) to a pH comprised in the range of from 5 to 12;

(4) optionally aging the mixture obtained in (3), preferably for a duration comprised in the range of from 10 to 120 minutes;

(5) isolating the solids from the mixture obtained in (3) or (4);

(6) optionally washing the solids obtained in (5);

(7) drying the solids obtained in (5) or (6); and

(8) calcining the solids obtained in (5), (6), or (7).

It is preferred that the pH of the solvent system of the mixture prepared in (1) is comprised in the range of from 3 to 8, more preferably from 4 to 7, more preferably from 5 to 6, and more preferably from 5.3 to 5.7.

It is preferred that in (2) the mixture prepared in (1) is heated to a temperature comprised in the range of from 40 to 80 °C, more preferably from 50 to 70 °C, and more preferably 55 to 65 °C.

It is preferred that in (3) the pH of the mixture obtained in (2) is adjusted to a pH comprised in the range of from 6 to 11, more preferably from 7 to 10, more preferably from 8 to 9, and more preferably from 8.3 to 8.7.

It is preferred that in (3) the adjustment of the pH is gradually performed in incremental steps over a time period comprised in the range of from 10 to 50 minutes, more preferably from 20 to 40 minutes, more preferably from 25 to 35 minutes, and more preferably from 27 to 32 minutes.

It is preferred that in (3) the adjustment of the pH is performed at a temperature comprised in the range of from 30 to 90 °C, more preferably from 40 to 80 °C, more preferably from 50 to 70 °C, and more preferably 55 to 65 °C. It is preferred that in (4) the mixture obtained in (3) is aged for a duration comprised in the range of from 20 to 100 minutes, more preferably from 30 to 90 minutes, more preferably from 40 to 80 minutes, more preferably from 50 to 70 minutes, and more preferably from 55 to 65 minutes.

It is preferred that in (4) the mixture obtained in (3) is aged at a temperature comprised in the range of from 30 to 90 °C, more preferably from 40 to 80 °C, more preferably from 50 to 70 °C, and more preferably 55 to 65 °C.

It is preferred that during aging in (4) a gas comprising oxygen is fed into the mixture, wherein more preferably the gas comprises air, wherein more preferably air is used as the gas compris ing oxygen.

It is preferred that the layered double hydroxide compound comprises positively charged main metal layers of the formula (I)

[Mΐ _cNc(OH)₂]^c+ (I) wherein M is a divalent element and N is a trivalent element, wherein 0.2 < x < 0.33, more pref erably wherein 0.22 < x < 0.29, more preferably wherein 0.24 < x < 0.27, more preferably wherein x = 0.25, and wherein the layered double hydroxide compound comprises intercalating anions between the main metal layers.

In the case where M is a divalent element, it is preferred that M comprises one or more ele ments selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn, including mix tures of two or more thereof, more preferably from the list consisting of Mg, Ca, Ni, and Zn, in cluding mixtures of two or more thereof, more preferably from the list consisting of Mg, Ca, and Zn, including mixtures of two or more thereof, wherein M preferably comprises Mg and/or Ca, preferably Mg, wherein more preferably M is Mg and/or Ca, preferably Mg.

In case where N is a trivalent element, it is preferred that N comprises one or more elements selected from the group consisting of Al, B, In, and Ga, including mixtures of two or more there of, wherein morepreferably N comprises Al and/or Ga, preferably Al, wherein more preferably N is Al and/or Ga, preferably Al.

In case where the layered double hydroxide compound comprises intercalating anions between the main metal layers, it is preferred that the intercalating anions are selected from the group consisting of chloride, bromide, nitrate, carbonate, and sulfate, including mixtures of two or more thereof, more preferably from the group consisting of chloride, carbonate, and sulfate, including mixtures of two or more thereof, wherein more preferably the intercalating anions comprise carbonate and/or sulfate, preferably carbonate, wherein more preferably the interca lating anions are carbonate and/or sulfate, preferably carbonate.

It is preferred that the layered double hydroxide compound comprises intercalated H₂0. It is preferred that the layered double hydroxide compounds comprises hydrotalcite, wherein more preferably the layered double hydroxide compound is hydrotalcite.

It is preferred that the one or more transition metals T is selected from the group consisting of Fe, Co, Ni, Pt, Rh, and Pd, including mixtures of two or more thereof, more preferably from the group consisting of Fe, Co, Ni, Pt, Rh, and Pd, including mixtures of two or more thereof, where in more preferably the one or more transition metals T is Ni.

It is preferred that the one or more sources of the one or more transition metals T comprises one or more salts, wherein more preferably the one or more salts are selected from the group consisting of halides, hydroxides, carbonates, nitrates, sulfates, and acetates, including mix tures of two or more thereof, more preferably from the group consisting of chlorides, bromides, carbonates, nitrates, and sulfates, including mixtures of two or more thereof, wherein more preferably the one or more sources of the one or more transition metals T comprises one or more nitrates.

It is preferred that the one or more sources of the one or more transition metals T comprises, more preferably consists of, nickel nitrate.

It is preferred that in (1 ) the solvent system comprises one or more polar solvents, more prefer ably one or more polar protic solvents, more preferably one or more polar protic solvents se lected from the group consisting of C1-C4 alcohols, water, dimethylformamide, and mixtures of two or more thereof, more preferably from the group consisting of n-propanol, isopropanol, methanol, ethanol, water, and mixtures of two or more thereof, more preferably from the group consisting of methanol, ethanol, dimethylformamide, water, and mixtures of two or more thereof, wherein more preferably the solvent system comprises ethanol and/or water, preferably water, wherein more preferably the solvent system consists of ethanol and/or water, preferably of wa ter.

It is preferred that in (3) the pH of the mixture obtained in (2) is adjusted using a base, more preferably using a Lewis base and/or a Bronsted base, more preferably using a Bronsted base, more preferably using a base selected from the group consisting of hydrogen phosphates, am monia, hydroxides, and carbonates, including mixtures of two or more thereof, preferably from the group consisting of ammonia, hydroxides, and carbonates, including mixtures of two or more thereof, wherein more preferably the mixture obtained in (2) is adjusted using carbonates, preferably using alkali metal carbonates, and more preferably using sodium carbonate.

In the case where in (3) the pH of the mixture obtained in (2) is adjusted using a base, more preferably using a Lewis base and/or a Bronsted base, it is preferred that the base is provided as an aqueous solution, wherein the aqueous solution comprising the base preferably has a concentration of the base in the range of from 1 to 70 weight-%, preferably of from 3 to 50 weight-%, more preferably of from 5 to 40weight-%, more preferably of from 10 to 30 weight-%, more preferably of from 15 to 25 weight-%, and more preferably of from 18 to 22 weight-%. ln case where in (3) the pH of the mixture obtained in (2) is adjusted using a base, more prefer ably using a Lewis base and/or a Bronsted base, it is preferred that the base is dissolved in a solvent system, wherein the solvent system comprises one or more polar solvents, preferably one or more polar protic solvents, more preferably one or more polar protic solvents selected from the group consisting of C1-C4 alcohols, water, dimethylformamide, and mixtures of two or more thereof, more preferably from the group consisting of n-propanol, isopropanol, methanol, ethanol, water, and mixtures of two or more thereof, more preferably from the group consisting of methanol, ethanol, dimethylformamide, water, and mixtures of two or more thereof, wherein more preferably the solvent system comprises ethanol and/or water, preferably water, wherein more preferably the solvent system consists of ethanol and/or water, preferably of water.

It is preferred that isolating in (5) is performed by filtration.

It is preferred that optionally washing in (6) is performed with a solvent system, wherein the sol vent system comprises one or more polar solvents, more preferably one or more polar protic solvents, more preferably one or more polar protic solvents selected from the group consisting of C1-C4 alcohols, water, dimethylformamide, and mixtures of two or more thereof, more pref erably from the group consisting of n-propanol, isopropanol, methanol, ethanol, water, and mix tures of two or more thereof, more preferably from the group consisting of methanol, ethanol, dimethylformamide, water, and mixtures of two or more thereof, wherein more preferably the solvent system comprises ethanol and/or water, preferably water, wherein more preferably the solvent system consists of ethanol and/or water, preferably of water.

It is preferred that drying in (7) is performed at a temperature comprised in the range of from 60 to 160 °C, more preferably from 70 to 150 °C, more preferably from 80 to 140 °C, more prefera bly from 90 to 130 °C, and more preferably from 100 to 120 °C.

It is preferred that calcining in (8) is performed at a temperature comprised in the range of from 100 to 700 °C, more preferably from 200 to 600 °C, more preferably from 300 to 500 °C, more preferably from 350 to 450 °C, and more preferably from 375 to 425 °C.

It is preferred that calcining in (8) is performed for a duration comprised in the range of from 10 to 110 minutes, more preferably from 20 to 100 minutes, more preferably from 30 to 90 minutes, more preferably from 40 to 80 minutes, more preferably from 50 to 70 minutes, and more pref erably from 55 to 65 minutes.

It is preferred that the process further comprises

(9) optional milling of the solids obtained in (8);

(10) optional shaping of the solids obtained in (8) or (9) into a shaped body; and

(11 ) calcining of the solids obtained in (8), (9), or (10).

In case where the process further comprises (9) optional milling of the solids obtained in (8); (10) optional shaping of the solids obtained in (8) or (9) into a shaped body; and

(11 ) calcining of the solids obtained in (8), (9), or (10), it is preferred that calcining in (11 ) is performed at a temperature comprised in the range of from 600 to 1300 °C, more preferably from 700 to 1200 °C, more preferably from 800 to 1150 °C, more preferably from 900 to 1100 °C, and more preferably from 950 to 1080 °C.

In case where the process further comprises

(9) optional milling of the solids obtained in (8);

(11 ) calcining of the solids obtained in (8), (9), or (10), it is preferred that calcining in (11 ) is performed for a duration comprised in the range of from 1 to 7 hours, more preferably from 2 to 6 hours, more preferably from 3 to 5 hours, and more preferably from 3.5 to 4.5 hours.

It is preferred that in (1) the molar ratio T : M of the one or more transition metals T to the one or more divalent elements M in the layered double hydroxide compound is comprised in the range of from 0.01 to 1.5, more preferably of from 0.05 to 1, more preferably of from 0.1 to 0.75, more preferably of from 0.15 to 0.5, more preferably of from 0.18 to 0.35, more preferably of from 0.2 to 0.3.

It is preferred that in (1) the molar ratio T : N of the one or more transition metals T to the one or more trivalent elements N in the layered double hydroxide compound is comprised in the range of from 0.1 to 5, more preferably of from 0.3 to 3, more preferably of from 0.5 to 1.5, more pref erably of from 0.55 to 1 , more preferably of from 0.6 to 0.75, more preferably of from 0.65 to 0.7.

It is preferred that the layered double hydroxide compound has a BET specific surface area in the range of from 200 to 350 m²/g, more preferably in the range of from 225 to 320 m²/g, more preferably in the range of from 250 to 310 m²/g, determined according to Reference Example 1 .

It is preferred that the layered double hydroxide compound has a loose bulk density in the range of from 0.10 to 0.80 g/ml, more preferably in the range of from 0.25 to 0.65 g/ml, more prefera bly in the range of from 0.3 to 0.6 g/ml.

It is preferred that the layered double hydroxide compound has a pore volume in the range of from 0.20 to 0.90 g/ml, more preferably in the range of from 0.40 to 0.70 g/ml, more preferably in the range of from 0.45 to 0.60 g/ml, preferably determined after activation under air for 3 h at 550 °C.

It is preferred that the layered double hydroxide compound is in particulate form, wherein from 77 to 97 weight-%, more preferably from 82 to 94 weight-%, more preferably from 85 to 91 weight-%, of the particles of the layered double hydroxide compound have a maximum diameter smaller than 90 micrometer, preferably determined by laser diffraction spectroscopy. It is preferred that the layered double hydroxide compound is in particulate form, wherein from 32 to 70 weight-%, more preferably from 38 to 64 weight-%, more preferably from 41 to 61 weight-%, of the particles of the layered double hydroxide compound have a maximum diameter smaller than 45 micrometer, preferably determined by laser diffraction spectroscopy.

It is preferred that the layered double hydroxide compound is in particulate form, wherein from 12 to 50 weight-%, more preferably from 16 to 46 weight-%, more preferably from 19 to 43 weight-%, of the particles of the layered double hydroxide compound have a maximum diameter smaller than 25 micrometer, preferably determined by laser diffraction spectroscopy.

It is preferred that from 95 to 100 weight-%, more preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, more prefera bly from 99.9 to 100 weight-%, of the mixture obtained from (1 ) consist of the solvent system, the layered double hydroxide compound, and the one or more sources of one or more transition metals T.

The present invention also relates to a mixed metal oxide obtainable or obtained according to the process of any of the particular and preferred embodiment of the present invention.

It is preferred that the mixed metal oxide comprises O, Mg, and Ni, wherein the mixed metal oxide comprises a crystalline phase Ni_xMg_yO, wherein the sum of x and y is 1 , and wherein y is greater than 0.52, wherein more preferably y is in the range of from 0.53 to 0.95, more prefera bly in the range of from 0.55 to 0.85, more preferably in the range of from 0.58 to 0.75, more preferably in the range of from 0.60 to 0.70, more preferably in the range of from 0.62 to 0.68, more preferably in the range of from 0.64 to 0.67, more preferably in the range of from 0.65 to 0.66, wherein the crystalline phase Ni_xMg_yO and its stoichiometry is preferably determined ac cording to Reference Example 2.

It is preferred that the mixed metal oxide further comprises a crystalline phase Ni_aMg_bO, where in the sum of a and b is 1 , and wherein a is equal or greater than 0.70, more preferably in the range of from 0.71 to 0.99, more preferably in the range of from 0.73 to 0.98, more preferably in the range of from 0.75 to 0.95, more preferably in the range of from 0.78 to 0.92, more prefera bly in the range of from 0.80 to 0.90, more preferably in the range of from 0.82 to 0.88, more preferably in the range of from 0.84 to 0.87, more preferably in the range of from 0.85 to 0.86, wherein x is not equal to a, and wherein the crystalline phase Ni_aMg O and its stoichiometry is preferably determined according to Reference Example 2.

It is preferred that in the mixed metal oxide the molar ratio of nickel to magnesium, Ni : Mg, each calculated as elemental Ni and Mg respectively, is in the range of from 0.20 : 1 to 0.75 : 1 , more preferably in the range of from 0.40 : 1 to 0.74 : 1 , more preferably in the range of from 0.43 : 1 to 0.56 : 1 , more preferably in the range of from 0.45 : 1 to 0.52 : 1, more preferably in the range of from 0.48 : 1 to 0.49 : 1. It is preferred that wherein from 10 to 20 weight-%, more preferably from 14 to 18 weight-%, more preferably from 15 to 17 weight-%, more preferably from 15 to 16 weight-%, of the mixed metal oxide consist of Ni, calculated as elemental Ni.

It is preferred that from 5 to 20 weight-%, more preferably from 11 to 15 weight-%, more prefer ably from 12.5 to 13.5 weight-%, of the mixed metal oxide consist of Mg, calculated as ele mental Mg.

It is preferred that the mixed metal oxide further comprises a metal M, wherein M is selected from the group consisting of Al, Ga, In, Si, Ge, Sn, Ti and Zr, more preferably from the group consisting of Al, Si and Ti, wherein the metal M more preferably is Al.

In case where the mixed metal oxide further comprises a metal M, wherein M is selected from the group consisting of Al, Ga, In, Si, Ge, Sn, Ti and Zr, preferably from the group consisting of Al, Si and Ti, wherein the metal M more preferably is Al, it is preferred that in the mixed metal oxide the molar ratio of nickel to the metal M, Ni : M, each calculated as elemental metal M and Ni respectively, is in the range of from 0.05 : 1 to 0.70 : 1 , more preferably in the range of from 0.10 : 1 to 0.50 : 1 , more preferably in the range of from 0.20 : 1 to 0.30 : 1 , more preferably in the range of from 0.23 : 1 to 0.25 : 1.

In case the mixed metal oxide further comprises a metal M, wherein M is selected from the group consisting of Al, Ga, In, Si, Ge, Sn, Ti and Zr, preferably from the group consisting of Al,

Si and Ti, wherein the metal M more preferably is Al, it is preferred that in the mixed metal oxide the molar ratio Mg : M of magnesium to the metal M, each calculated as elemental Mg and met al M respectively, is in the range of from 0.20 : 1 to 0.80 : 1 , more preferably in the range of from 0.40 : 1 to 0.60 : 1 , more preferably in the range of from 0.47 : 1 to 0.53 : 1 , more prefera bly in the range of from 0.48 : 1 to 0.50 : 1.

In case where the mixed metal oxide further comprises a metal M, it is preferred that from 20 to 40 weight-%, more preferably from 28 to 31.5 weight-%, more preferably from 28.5 to 30 weight-%, of the mixed metal oxide consist of the metal M, calculated as elemental metal M.

In case where the mixed metal oxide further comprises a metal M, it is preferred that the metal M is Al, and wherein the mixed metal oxide further comprises a crystalline phase MgAI₂0₄.

In case where the metal M is Al, and wherein the mixed metal oxide further comprises a crystal line phase MgAI₂0₄, it is preferred that the average particle size of the crystals of the crystalline phase MgAI₂0₄ is in the range of from 1 to 70 nm, more preferably in the range of from 3 to 40 nm, more preferably in the range of from 6 to 25 nm, more preferably in the range of from 8 to 15 nm, more preferably in the range of from 9 to 13 nm, more preferably in the range of from 10 to 11 nm, as determined according to Reference Example 2. It is preferred that the mixed metal oxide comprises from 0 to 1 weight-%, more preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase AI2O3, wherein the mixed metal oxide more preferably is essentially free of a crystalline phase AI2O3, wherein the mixed metal oxide more preferably does not comprise a crystalline phase AI2O3.

It is preferred that the mixed metal oxide comprises from 0 to 1 weight-%, more preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase NiAI₂0 , wherein the mixed metal oxide more preferably is essentially free of a crystalline phase N1AI2O4, wherein the mixed metal oxide more preferably does not comprise a crystalline phase N1AI2O4.

It is preferred that the mixed metal oxide comprises from 0 to 1 weight-%, more preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase NiO, wherein the mixed metal oxide more preferably is essentially free of a crystalline phase NiO, wherein the mixed metal oxide more preferably does not comprise a crystalline phase NiO.

It is preferred that the mixed metal oxide comprises from 0 to 1 weight-%, more preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase MgO, wherein the mixed metal oxide more preferably is essentially free of a crystalline phase MgO, wherein the mixed metal oxide more preferably does not comprise a crystalline phase MgO.

It is preferred that from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, more preferably from 99.9 to 100 weight-% of the mixed metal oxide consist of O, Mg, Ni, optionally a metal M as defined in any of the particular and preferred embodiments of the present invention, and optionally H.

It is preferred that the mixed metal oxide comprises the crystalline phase Ni_xMg_yO, in an amount in the range of from 1 to 50 weight-%, more preferably in the range of from 5 to 40 weight-%, more preferably in the range of from 10 to 30 weight-%, more preferably in the range of from 12 to 28 weight-%, more preferably in the range of from 15 to 25 weight-%, more preferably in the range of from 18 to 23 weight-%, more preferably in the range of from 20 to 21 weight-%, based on the total weight of the mixed metal oxide.

It is preferred that the mixed metal oxide comprises a crystalline phase Ni_aMg_bO, in an amount of equal to or less than 20 weight-%, more preferably equal to or less than 15 weight-%, more preferably equal to or less than 10 weight-%, more preferably equal to or less than 5 weight-%, more preferably equal to or less than 2 weight-%, more preferably equal to or less than 1 weight-%, more preferably equal to or less than 0.5 weight-%, more preferably equal to or less than 0.1 weight-%, more preferably equal to or less than 0.05 weight-%, more preferably equal to or less than 0.01 weight-%, based on the total weight of the mixed metal oxide.

It is preferred that the lattice parameter a of the crystalline phase Ni_xMg_yO is in the range of from 4.191 to 4.208 Angstrom, more preferably in the range of from 4.195 to 4.203, more pref- erably in the range of from 4.1990 to 4.1995, wherein the lattice parameter a is preferably de termined according to Reference Example 2.

It is preferred that the lattice parameter a of the crystalline phase Ni_aMg_bO is in the range of from 4.172 to 4.190 Angstrom, more preferably in the range of from 4.177 to 4.186, more pref erably in the range of from 4.1815 to 4.1820, wherein the lattice parameter a is preferably de termined according to Reference Example 2.

It is preferred that the mixed metal oxide exhibits an X-ray diffraction spectrum, determined as described in Reference Example 2, wherein the X-ray diffraction spectrum comprises a first peak having a maximum in the range of from 19.0 to 19.9 °2theta, and a second peak having a maximum in the range of from 20.0 to 21.0 °2theta.

In case where the mixed metal oxide exhibits an X-ray diffraction spectrum, determined as de scribed in Reference Example 2, wherein the X-ray diffraction spectrum comprises a first peak having a maximum in the range of from 19.0 to 19.9 °2theta, and a second peak having a max imum in the range of from 20.0 to 21 .0 °2theta, it is preferred that the intensity of the maximum of the first peak, calculated as peak height in arbitrary units, is equal to or less than the intensity of the maximum of the second peak, calculated as peak height in arbitrary units, wherein the ratio of the intensity of the maximum of the first peak to the intensity of the maximum of the sec ond peak is in the range of from 0.3:1 to 1:1, more preferably in the range of from 0.5:1 to 0.99:1 , more preferably in the range of from 0.6:1 to 0.95:1, more preferably in the range of from 0.7:1 to 0.86:1 , more preferably in the range of from 0.78:1 to 0.80:1.

It is preferred that the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature programmed reduction profile comprises a first peak having a maxi mum in the range of from 700 to 840 °C, more preferably in the range of from 750 to 825 °C, wherein the temperature programmed reduction profile preferably is determined according to Reference Example 3.

It is preferred that the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature programmed reduction profile comprises a second peak having a max imum in the range of from 850 to 950 °C, more preferably in the range of from 875 to 925 °C, wherein the temperature programmed reduction profile preferably is determined according to Reference Example 3.

It is preferred that the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature programmed reduction profile comprises a third peak having a maxi mum in the range of from 300 to 600 °C, more preferably in the range of from 350 to 550 °C, wherein the temperature programmed reduction profile preferably is determined according to Reference Example 3. It is preferred that the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature programmed reduction profile shows a total hydrogen consumption in the range of from 0 to 1000 pmol H₂/g mixed metal oxide, more preferably in the range of from 5 to 800 pmol H₂/g mixed metal oxide, more preferably in the range of from 10 to 700 pmol H₂/g mixed metal oxide, more preferably in the range of from 20 to 600 pmol H₂/g mixed metal oxide, more preferably in the range of from 30 to 550 pmol H₂/g mixed metal oxide, more preferably in the range of from 40 to 500 pmol H₂/g mixed metal oxide, and more preferably in the range of from 50 to 450 pmol H₂/g mixed metal oxide, at a temperature below 600 °C, preferably in the range of from 0 to 600 °C, more preferably in the range of from 50 to 600 °C, wherein the tem perature programmed reduction profile preferably is determined according to Reference Exam ple 3.

It is preferred that the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature programmed reduction profile shows a total hydrogen consumption in the range of from 1300 to 3000 pmol H₂/g mixed metal oxide, more preferably in the range of from 1500 to 2800 pmol H₂/g mixed metal oxide, more preferably in the range of from 1700 to 2600 pmol H₂/g mixed metal oxide, at a temperature above 600 °C, preferably in the range of from 600 to 1000 °C, more preferably in the range of from 600 to 950 °C, wherein the tempera ture programmed reduction profile preferably is determined according to Reference Example 3.

The present invention also relates to a method for reforming one or more hydrocarbons, prefer ably for reforming methane, to a synthesis gas comprising hydrogen and carbon monoxide, the method comprising

(a) providing a reactor comprising a reaction zone which comprises the mixed metal oxide according to any of the particular and preferred embodiments of the present invention;

(b) passing a reactant gas stream into the reaction zone obtained from (a), wherein the reac tant gas stream passed into the reaction zone comprises the one or more hydrocarbons, carbon dioxide, and water; subjecting said reactant gas stream to reforming conditions in said reaction zone; and removing a product stream from said reaction zone, said product stream comprising hydrogen and carbon monoxide.

The present invention also relates to the use of the mixed metal oxide according to any of the particular and preferred embodiment of the present invention as a catalytically active material, as a catalyst component or as a catalyst, preferably for reforming one or more hydrocarbons, wherein the hydrocarbons are preferably selected from the group consisting of methane, ethane, propane, butane, and a mixture of two or more thereof, wherein the hydrocarbons are more preferably methane, to a synthesis gas comprising hydrogen and carbon monoxide, pref erably in the presence of one or more of carbon dioxide and steam.

The present invention is further illustrated by the following set of embodiments and combina tions of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for ex ample in the context of a term such as "The process of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the word ing of this term is to be understood by the skilled person as being synonymous to "The process of any one of embodiments 1 , 2, 3, and 4". Further, it is explicitly noted that the following set of embodiments is not the set of claims determining the extent of protection, but represents a suit ably structured part of the description directed to general and preferred aspects of the present invention.

1. A process for the preparation of a mixed metal oxide comprising one or more transition metals T, one or more divalent elements M, one or more trivalent elements N, and O, the process comprising

(1 ) preparing a mixture comprising a solvent system, a layered double hydroxide com pound, and one or more sources of one or more transition metals T, wherein the layered double hydroxide compound comprises one or more divalent elements M and one or more trivalent elements N, and wherein the pH of the solvent system is comprised in the range of from 2 to 9;

(5) isolating the solids from the mixture obtained in (3) or (4);

(6) optionally washing the solids obtained in (5);

(7) drying the solids obtained in (5) or (6); and

(8) calcining the solids obtained in (5), (6), or (7).

2. The process of embodiment 1 , wherein the pH of the solvent system of the mixture pre pared in (1) is comprised in the range of from 3 to 8, preferably from 4 to 7, more prefera bly from 5 to 6, and more preferably from 5.3 to 5.7.

3. The process of embodiment 1 or 2, wherein in (2) the mixture prepared in (1 ) is heated to a temperature comprised in the range of from 40 to 80 °C, preferably from 50 to 70 °C, and more preferably 55 to 65 °C.

4. The process of any of embodiments 1 to 3, wherein in (3) the pH of the mixture obtained in (2) is adjusted to a pH comprised in the range of from 6 to 11, preferably from 7 to 10, more preferably from 8 to 9, and more preferably from 8.3 to 8.7.

5. The process of any of embodiments 1 to 4, wherein in (3) the adjustment of the pH is gradually performed in incremental steps over a time period comprised in the range of from 10 to 50 minutes, preferably from 20 to 40 minutes, more preferably from 25 to 35 minutes, and more preferably from 27 to 32 minutes. The process of any of embodiments 1 to 5, wherein in (3) the adjustment of the pH is per formed at a temperature comprised in the range of from 30 to 90 °C, preferably from 40 to 80 °C, more preferably from 50 to 70 °C, and more preferably 55 to 65 °C. The process of any of embodiments 1 to 6, wherein in (4) the mixture obtained in (3) is aged for a duration comprised in the range of from 20 to 100 minutes, preferably from 30 to 90 minutes, more preferably from 40 to 80 minutes, more preferably from 50 to 70 minutes, and more preferably from 55 to 65 minutes. The process of any of embodiments 1 to 7, wherein in (4) the mixture obtained in (3) is aged at a temperature comprised in the range of from 30 to 90 °C, preferably from 40 to 80 °C, more preferably from 50 to 70 °C, and more preferably 55 to 65 °C. The process of any of embodiments 1 to 8, wherein during aging in (4) a gas comprising oxygen is fed into the mixture, wherein preferably the gas comprises air, wherein more preferably air is used as the gas comprising oxygen. The process of any of embodiments 1 to 9, wherein the layered double hydroxide com pound comprises positively charged main metal layers of the formula (I)

[M_I-XN_X(OH)₂]^x+ (I) wherein M is a divalent element and N is a trivalent element, wherein 0.2 £ x £ 0.33, pref erably wherein 0.22 < x < 0.29, more preferably wherein 0.24 < x < 0.27, more preferably wherein x = 0.25, and wherein the layered double hydroxide compound comprises interca lating anions between the main metal layers. The process of embodiment 10, wherein M comprises one or more elements selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn, including mixtures of two or more thereof, preferably from the list consisting of Mg, Ca, Ni, and Zn, including mix tures of two or more thereof, more preferably from the list consisting of Mg, Ca, and Zn, including mixtures of two or more thereof, wherein M preferably comprises Mg and/or Ca, preferably Mg, wherein more preferably M is Mg and/or Ca, preferably Mg. The process of embodiment 10 or 11, wherein N comprises one or more elements select ed from the group consisting of Al, B, In, and Ga, including mixtures of two or more there of, wherein N preferably comprises Al and/or Ga, preferably Al, wherein more preferably N is Al and/or Ga, preferably Al. The process of any of embodiments 10 to 12, wherein the intercalating anions are select ed from the group consisting of chloride, bromide, nitrate, carbonate, and sulfate, includ ing mixtures of two or more thereof, preferably from the group consisting of chloride, car bonate, and sulfate, including mixtures of two or more thereof, wherein more preferably the intercalating anions comprise carbonate and/or sulfate, preferably carbonate, wherein more preferably the intercalating anions are carbonate and/or sulfate, preferably car bonate. The process of any of embodiments 1 to 13, wherein the layered double hydroxide com pound comprises intercalated H₂0. The process of any of embodiments 1 to 14, wherein the layered double hydroxide com pounds comprises hydrotalcite, wherein preferably the layered double hydroxide com pound is hydrotalcite. The process of any of embodiments 1 to 15, wherein the one or more transition metals T is selected from the group consisting of Fe, Co, Ni, Pt, Rh, and Pd, including mixtures of two or more thereof, preferably from the group consisting of Fe, Co, Ni, Pt, Rh, and Pd, including mixtures of two or more thereof, wherein more preferably the one or more transi tion metals T is Ni. The process of any of embodiments 1 to 16, wherein the one or more sources of the one or more transition metals T comprises one or more salts, wherein preferably the one or more salts are selected from the group consisting of halides, hydroxides, carbonates, ni trates, sulfates, and acetates, including mixtures of two or more thereof, more preferably from the group consisting of chlorides, bromides, carbonates, nitrates, and sulfates, in cluding mixtures of two or more thereof, wherein more preferably the one or more sources of the one or more transition metals T comprises one or more nitrates. The process of any of embodiments 1 to 17, wherein the one or more sources of the one or more transition metals T comprises, preferably consists of, nickel nitrate. The process of any of embodiments 1 to 18, wherein in (1 ) the solvent system comprises one or more polar solvents, preferably one or more polar protic solvents, more preferably one or more polar protic solvents selected from the group consisting of C1-C4 alcohols, water, dimethylformamide, and mixtures of two or more thereof, more preferably from the group consisting of n-propanol, isopropanol, methanol, ethanol, water, and mixtures of two or more thereof, more preferably from the group consisting of methanol, ethanol, dimethyl formamide, water, and mixtures of two or more thereof, wherein more preferably the sol vent system comprises ethanol and/or water, preferably water, wherein more preferably the solvent system consists of ethanol and/or water, preferably of water. The process of any of embodiments 1 to 19, wherein in (3) the pH of the mixture obtained in (2) is adjusted using a base, preferably using a Lewis base and/or a Bronsted base, more preferably using a Bronsted base, more preferably using a base selected from the group consisting of hydrogen phosphates, ammonia, hydroxides, and carbonates, includ ing mixtures of two or more thereof, preferably from the group consisting of ammonia, hy- droxides, and carbonates, including mixtures of two or more thereof, wherein more prefer ably the mixture obtained in (2) is adjusted using carbonates, preferably using alkali metal carbonates, and more preferably using sodium carbonate.

21. The process of embodiment 20, wherein the base is provided as an aqueous solution, wherein the aqueous solution comprising the base preferably has a concentration of the base in the range of from 1 to 70 weight-%, preferably of from 3 to 50 weight-%, more preferably of from 5 to 40weight-%, more preferably of from 10 to 30 weight-%, more pref erably of from 15 to 25 weight-%, and more preferably of from 18 to 22 weight-%.

22. The process of embodiment 20 or 21 , wherein the base is dissolved in a solvent system, wherein the solvent system comprises one or more polar solvents, preferably one or more polar protic solvents, more preferably one or more polar protic solvents selected from the group consisting of C1-C4 alcohols, water, dimethylformamide, and mixtures of two or more thereof, more preferably from the group consisting of n-propanol, isopropanol, methanol, ethanol, water, and mixtures of two or more thereof, more preferably from the group consisting of methanol, ethanol, dimethylformamide, water, and mixtures of two or more thereof, wherein more preferably the solvent system comprises ethanol and/or wa ter, preferably water, wherein more preferably the solvent system consists of ethanol and/or water, preferably of water.

23. The process of any of embodiments 1 to 22, wherein isolating in (5) is performed by filtra tion.

24. The process of any of embodiments 1 to 23, wherein optionally washing in (6) is per formed with a solvent system, wherein the solvent system comprises one or more polar solvents, preferably one or more polar protic solvents, more preferably one or more polar protic solvents selected from the group consisting of C1-C4 alcohols, water, dimethylfor mamide, and mixtures of two or more thereof, more preferably from the group consisting of n-propanol, isopropanol, methanol, ethanol, water, and mixtures of two or more thereof, more preferably from the group consisting of methanol, ethanol, dimethylformamide, wa ter, and mixtures of two or more thereof, wherein more preferably the solvent system comprises ethanol and/or water, preferably water, wherein more preferably the solvent system consists of ethanol and/or water, preferably of water.

25. The process of any of embodiments 1 to 24, wherein drying in (7) is performed at a tem perature comprised in the range of from 60 to 160 °C, preferably from 70 to 150 °C, more preferably from 80 to 140 °C, more preferably from 90 to 130 °C, and more preferably from 100 to 120 °C.

26. The process of any of embodiments 1 to 25, wherein calcining in (8) is performed at a temperature comprised in the range of from 100 to 700 °C, preferably from 200 to 600 °C, more preferably from 300 to 500 °C, more preferably from 350 to 450 °C, and more pref erably from 375 to 425 °C.

27. The process of any of embodiments 1 to 26, wherein calcining in (8) is performed for a duration comprised in the range of from 10 to 110 minutes, preferably from 20 to 100 minutes, more preferably from 30 to 90 minutes, more preferably from 40 to 80 minutes, more preferably from 50 to 70 minutes, and more preferably from 55 to 65 minutes.

28. The process of any of embodiments 1 to 27, wherein the process further comprises

(9) optional milling of the solids obtained in (8);

(11 ) calcining of the solids obtained in (8), (9), or (10).

29. The process of embodiment 28, wherein calcining in (11) is performed at a temperature comprised in the range of from 600 to 1300 °C, preferably from 700 to 1200 °C, more preferably from 800 to 1150 °C, more preferably from 900 to 1100 °C, and more prefera bly from 950 to 1080 °C.

30. The process of any of embodiment 28 or 29, wherein calcining in (11 ) is performed for a duration comprised in the range of from 1 to 7 hours, preferably from 2 to 6 hours, more preferably from 3 to 5 hours, and more preferably from 3.5 to 4.5 hours.

31. The process of any of embodiments 1 to 30, wherein in (1 ) the molar ratio T : M of the one or more transition metals T to the one or more divalent elements M in the layered double hydroxide compound is comprised in the range of from 0.01 to 1.5, more preferably of from 0.05 to 1, more preferably of from 0.1 to 0.75, more preferably of from 0.15 to 0.5, more preferably of from 0.18 to 0.35, more preferably of from 0.2 to 0.3.

32. The process of any of embodiments 1 to 31 , wherein in (1) the molar ratio T : N of the one or more transition metals T to the one or more trivalent elements N in the layered double hydroxide compound is comprised in the range of from 0.1 to 5, more preferably of from 0.3 to 3, more preferably of from 0.5 to 1.5, more preferably of from 0.55 to 1 , more pref erably of from 0.6 to 0.75, more preferably of from 0.65 to 0.7.

33. The process of any of embodiments 1 to 32, wherein the layered double hydroxide com pound has a BET specific surface area in the range of from 200 to 350 m²/g, preferably in the range of from 225 to 320 m²/g, more preferably in the range of from 250 to 310 m²/g, determined according to Reference Example 1.

34. The process of any of embodiments 1 to 33, wherein layered double hydroxide compound has a loose bulk density in the range of from 0.10 to 0.80 g/ml, preferably in the range of from 0.25 to 0.65 g/ml, more preferably in the range of from 0.3 to 0.6 g/ml. 35. The process of any of embodiments 1 to 34, wherein the layered double hydroxide com pound has a pore volume in the range of from 0.20 to 0.90 g/ml, preferably in the range of from 0.40 to 0.70 g/ml, more preferably in the range of from 0.45 to 0.60 g/ml, preferably determined after activation under air for 3 h at 550 °C.

36. The process of any of embodiments 1 to 35, wherein the layered double hydroxide com pound is in particulate form, wherein from 77 to 97 weight-%, preferably from 82 to 94 weight-%, more preferably from 85 to 91 weight-%, of the particles of the layered double hydroxide compound have a maximum diameter smaller than 90 micrometer, preferably determined by laser diffraction spectroscopy.

37. The process of any of embodiments 1 to 36, wherein the layered double hydroxide com pound is in particulate form, wherein from 32 to 70 weight-%, preferably from 38 to 64 weight-%, more preferably from 41 to 61 weight-%, of the particles of the layered double hydroxide compound have a maximum diameter smaller than 45 micrometer, preferably determined by laser diffraction spectroscopy.

38. The process of any of embodiments 1 to 37, wherein the layered double hydroxide com pound is in particulate form, wherein from 12 to 50 weight-%, preferably from 16 to 46 weight-%, more preferably from 19 to 43 weight-%, of the particles of the layered double hydroxide compound have a maximum diameter smaller than 25 micrometer, preferably determined by laser diffraction spectroscopy.

39. The process of any of embodiments 1 to 38, wherein from 95 to 100 weight-%, preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, more preferably from 99.9 to 100 weight-%, of the mixture obtained from (1 ) consist of the solvent system, the layered double hydroxide compound, and the one or more sources of one or more transition metals T.

40. A mixed metal oxide obtainable or obtained according to the process of any of embodi ments 1 to 39.

41. The mixed metal oxide of embodiment 40, wherein the mixed metal oxide comprises O, Mg, and Ni, wherein the mixed metal oxide comprises a crystalline phase Ni_xMg_yO, where in the sum ofx and y is 1, and wherein y is greater than 0.52, wherein preferably y is in the range of from 0.53 to 0.95, more preferably in the range of from 0.55 to 0.85, more preferably in the range of from 0.58 to 0.75, more preferably in the range of from 0.60 to 0.70, more preferably in the range of from 0.62 to 0.68, more preferably in the range of from 0.64 to 0.67, more preferably in the range of from 0.65 to 0.66, wherein the crystal line phase Ni_xMg_yO and its stoichiometry is preferably determined according to Reference Example 2. 42. The mixed metal oxide of embodiment 40 or 41 , wherein the mixed metal oxide further comprises a crystalline phase Ni_aMg O, wherein the sum of a and b is 1 , and wherein a is equal or greater than 0.70, preferably in the range of from 0.71 to 0.99, more preferably in the range of from 0.73 to 0.98, more preferably in the range of from 0.75 to 0.95, more preferably in the range of from 0.78 to 0.92, more preferably in the range of from 0.80 to 0.90, more preferably in the range of from 0.82 to 0.88, more preferably in the range of from 0.84 to 0.87, more preferably in the range of from 0.85 to 0.86, wherein x is not equal to a, and wherein the crystalline phase Ni_aMg_bO and its stoichiometry is preferably deter mined according to Reference Example 2.

43. The mixed metal oxide of any of embodiments 40 to 42, wherein in the mixed metal oxide the molar ratio of nickel to magnesium, Ni : Mg, each calculated as elemental Ni and Mg respectively, is in the range of from 0.20 : 1 to 0.75 : 1 , preferably in the range of from 0.40 : 1 to 0.74 : 1 , more preferably in the range of from 0.43 : 1 to 0.56 : 1, more prefera bly in the range of from 0.45 : 1 to 0.52 : 1, more preferably in the range of from 0.48 : 1 to 0.49 : 1.

44. The mixed metal oxide of any of embodiments 40 to 43, wherein from 10 to 20 weight-%, preferably from 14 to 18 weight-%, more preferably from 15 to 17 weight-%, more prefer ably from 15 to 16 weight-%, of the mixed metal oxide consist of Ni, calculated as ele mental Ni.

45. The mixed metal oxide of any of embodiments 40 to 44, wherein from 5 to 20 weight-%, preferably from 11 to 15 weight-%, more preferably from 12.5 to 13.5 weight-%, of the mixed metal oxide consist of Mg, calculated as elemental Mg.

46. The mixed metal oxide of any of embodiments 40 to 45, wherein the mixed metal oxide further comprises a metal M, wherein M is selected from the group consisting of Al, Ga, In, Si, Ge, Sn, Ti and Zr, preferably from the group consisting of Al, Si and Ti, wherein the metal M more preferably is Al.

47. The mixed metal oxide of embodiment 46, wherein in the mixed metal oxide the molar ratio of nickel to the metal M, Ni : M, each calculated as elemental metal M and Ni respec tively, is in the range of from 0.05 : 1 to 0.70 : 1 , preferably in the range of from 0.10 : 1 to 0.50 : 1, more preferably in the range of from 0.20 : 1 to 0.30 : 1 , more preferably in the range of from 0.23 : 1 to 0.25 : 1.

48. The mixed metal oxide of embodiment 46 or 47, wherein in the mixed metal oxide the mo lar ratio Mg : M of magnesium to the metal M, each calculated as elemental Mg and metal M respectively, is in the range of from 0.20 : 1 to 0.80 : 1 , preferably in the range of from 0.40 : 1 to 0.60 : 1 , more preferably in the range of from 0.47 : 1 to 0.53 : 1, more prefera bly in the range of from 0.48 : 1 to 0.50 : 1. The mixed metal oxide of any of embodiments 46 to 48, wherein from 20 to 40 weight-%, preferably from 28 to 31.5 weight-%, more preferably from 28.5 to 30 weight-%, of the mixed metal oxide consist of the metal M, calculated as elemental metal M. The mixed metal oxide of any of embodiments 46 to 49, wherein the metal M is Al, and wherein the mixed metal oxide further comprises a crystalline phase MgAI₂04. The mixed metal oxide of embodiment 50, wherein the average particle size of the crys tals of the crystalline phase MgA 0₄ is in the range of from 1 to 70 nm, preferably in the range of from 3 to 40 nm, more preferably in the range of from 6 to 25 nm, more prefera bly in the range of from 8 to 15 nm, more preferably in the range of from 9 to 13 nm, more preferably in the range of from 10 to 11 nm, as determined according to Reference Exam ple 2. The mixed metal oxide of any of embodiments 40 to 51 , wherein the mixed metal oxide comprises from 0 to 1 weight-%, preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase AI2O3, wherein the mixed metal oxide more preferably is essentially free of a crystalline phase AI2O3, wherein the mixed metal oxide more preferably does not comprise a crystalline phase AI2O3. The mixed metal oxide of any of embodiments 40 to 52, wherein the mixed metal oxide comprises from 0 to 1 weight-%, preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase NiAI₂0₄, wherein the mixed metal oxide more preferably is essentially free of a crystalline phase NiAI₂0₄, wherein the mixed metal oxide more preferably does not comprise a crystalline phase NiA C . The mixed metal oxide of any of embodiments 40 to 53, wherein the mixed metal oxide comprises from 0 to 1 weight-%, preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase NiO, wherein the mixed metal oxide more preferably is essentially free of a crystalline phase NiO, wherein the mixed metal ox ide more preferably does not comprise a crystalline phase NiO. The mixed metal oxide of any of embodiments 40 to 54, wherein the mixed metal oxide comprises from 0 to 1 weight-%, preferably from 0.001 to 0.1 weight-%, more preferably from 0.01 to 0.1 weight-%, of a crystalline phase MgO, wherein the mixed metal oxide more preferably is essentially free of a crystalline phase MgO, wherein the mixed metal oxide more preferably does not comprise a crystalline phase MgO. The mixed metal oxide of any of embodiments 40 to 55, wherein from 99 to 100 weight-%, preferably from 99.5 to 100 weight-%, more preferably from 99.9 to 100 weight-% of the mixed metal oxide consist of O, Mg, Ni, optionally a metal M as defined in any one of em bodiments 46 to 50, and optionally H. The mixed metal oxide of any of embodiments 40 to 56, wherein the mixed metal oxide comprises the crystalline phase Ni_xMg_yO, in an amount in the range of from 1 to 50 weight-%, preferably in the range of from 5 to 40 weight-%, more preferably in the range of from 10 to 30 weight-%, more preferably in the range of from 12 to 28 weight-%, more preferably in the range of from 15 to 25 weight-%, more preferably in the range of from 18 to 23 weight-%, more preferably in the range of from 20 to 21 weight-%, based on the total weight of the mixed metal oxide. The mixed metal oxide of any of embodiments 40 to 57, wherein the mixed metal oxide comprises a crystalline phase Ni_aMg_bO, in an amount of equal to or less than 20 weight- %, preferably equal to or less than 15 weight-%, more preferably equal to or less than 10 weight-%, more preferably equal to or less than 5 weight-%, more preferably equal to or less than 2 weight-%, more preferably equal to or less than 1 weight-%, more preferably equal to or less than 0.5 weight-%, more preferably equal to or less than 0.1 weight-%, more preferably equal to or less than 0.05 weight-%, more preferably equal to or less than 0.01 weight-%, based on the total weight of the mixed metal oxide. The mixed metal oxide of any of embodiments 40 to 58, wherein the lattice parameter a of the crystalline phase Ni_xMg_yO is in the range of from 4.191 to 4.208 Angstrom, preferably in the range of from 4.195 to 4.203, more preferably in the range of from 4.1990 to 4.1995, wherein the lattice parameter a is preferably determined according to Reference Example 2. The mixed metal oxide of any of embodiments 40 to 59, wherein the lattice parameter a of the crystalline phase Ni_aMg_bO is in the range of from 4.172 to 4.190 Angstrom, preferably in the range of from 4.177 to 4.186, more preferably in the range of from 4.1815 to 4.1820, wherein the lattice parameter a is preferably determined according to Reference Example 2 The mixed metal oxide of any of embodiments 40 to 60, wherein the mixed metal oxide exhibits an X-ray diffraction spectrum, determined as described in Reference Example 2, wherein the X-ray diffraction spectrum comprises a first peak having a maximum in the range of from 19.0 to 19.9 °2theta, and a second peak having a maximum in the range of from 20.0 to 21.0 °2theta. The mixed metal oxide of embodiment 61 , wherein the intensity of the maximum of the first peak, calculated as peak height in arbitrary units, is equal to or less than the intensity of the maximum of the second peak, calculated as peak height in arbitrary units, wherein the ratio of the intensity of the maximum of the first peak to the intensity of the maximum of the second peak is in the range of from 0.3:1 to 1 :1, preferably in the range of from 0.5:1 to 0.99:1, more preferably in the range of from 0.6:1 to 0.95:1 , more preferably in the range of from 0.7:1 to 0.86:1 , more preferably in the range of from 0.78:1 to 0.80:1. The mixed metal oxide of any of embodiments 40 to 62, wherein the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature pro grammed reduction profile comprises a first peak having a maximum in the range of from 700 to 840 °C, preferably in the range of from 750 to 825 °C, wherein the temperature programmed reduction profile preferably is determined according to Reference Example 3. The mixed metal oxide of any of embodiments 40 to 63, wherein the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature pro grammed reduction profile comprises a second peak having a maximum in the range of from 850 to 950 °C, preferably in the range of from 875 to 925 °C, wherein the tempera ture programmed reduction profile preferably is determined according to Reference Ex ample 3. The mixed metal oxide of any of embodiments 40 to 64, wherein the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature pro grammed reduction profile comprises a third peak having a maximum in the range of from 300 to 600 °C, preferably in the range of from 350 to 550 °C, wherein the temperature programmed reduction profile preferably is determined according to Reference Example 3. The mixed metal oxide of any of embodiments 40 to 65, wherein the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature pro grammed reduction profile shows a total hydrogen consumption in the range of from 0 to 1000 pmol H2/g mixed metal oxide, preferably in the range of from 5 to 800 pmol H₂/g mixed metal oxide, more preferably in the range of from 10 to 700 pmol H₂/g mixed metal oxide, more preferably in the range of from 20 to 600 pmol H₂/g mixed metal oxide, more preferably in the range of from 30 to 550 pmol H₂/g mixed metal oxide, more preferably in the range of from 40 to 500 pmol H₂/g mixed metal oxide, and more preferably in the range of from 50 to 450 pmol H₂/g mixed metal oxide, at a temperature below 600 °C, preferably in the range of from 0 to 600 °C, more preferably in the range of from 50 to 600 °C, wherein the temperature programmed reduction profile preferably is determined ac cording to Reference Example 3. The mixed metal oxide of any of embodiments 40 to 66, wherein the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature pro grammed reduction profile shows a total hydrogen consumption in the range of from 1300 to 3000 pmol H₂/g mixed metal oxide, preferably in the range of from 1500 to 2800 pmol H₂/g mixed metal oxide, more preferably in the range of from 1700 to 2600 pmol H₂/g mixed metal oxide, at a temperature above 600 °C, preferably in the range of from 600 to 1000 °C, more preferably in the range of from 600 to 950 °C, wherein the temperature programmed reduction profile preferably is determined according to Reference Example 3. 68. A method for reforming one or more hydrocarbons, preferably for reforming methane, to a synthesis gas comprising hydrogen and carbon monoxide, the method comprising

(a) providing a reactor comprising a reaction zone which comprises the mixed metal ox ide according to any one of embodiments 40 to 67;

(b) passing a reactant gas stream into the reaction zone obtained from (a), wherein the reactant gas stream passed into the reaction zone comprises the one or more hydrocar bons, carbon dioxide, and water; subjecting said reactant gas stream to reforming condi tions in said reaction zone; and removing a product stream from said reaction zone, said product stream comprising hydrogen and carbon monoxide.

69. Use of the mixed metal oxide according to any of embodiments 40 to 67 as a catalytically active material, as a catalyst component or as a catalyst, preferably for reforming one or more hydrocarbons, wherein the hydrocarbons are preferably selected from the group consisting of methane, ethane, propane, butane, and a mixture of two or more thereof, wherein the hydrocarbons are more preferably methane, to a synthesis gas comprising hydrogen and carbon monoxide, preferably in the presence of one or more of carbon diox ide and steam.

EXPERIMENTAL SECTION

Reference Example 1 : Determination of the BET specific surface area and the Langmuir specific surface area

The BET specific surface area and the Langmuir specific surface area were determined via ni trogen physisorption at 77 K according to the method disclosed in DIN 66131.

Reference Example 2: Determination of crystallinity via XRD

Powder X-ray Diffraction (PXRD) data were collected using a laboratory diffractometer (D8 Dis cover, Bruker AXS GmbH, Karlsruhe). The instrument was set up with a Molybdenum X-ray tube. The characteristic K-alpha radiation was monochromatized using a bent Germanium Jo hansson type primary monochromator. Data were collected in the Bragg-Brentano reflection geometry. A LYNXEYE area detector was utilized to collect the scattered X-ray signal.

The powders were ground using an IKA Tube Mill and an MT40.100 disposable grinding cham ber. The powder was placed in a sample holder and flattened using a glass plate. Data analysis was performed using DIFFRAC.EVA V4 and DIFFRAC.TOPAS V4 software (Bruker AXS GmbH). DIFFRAC.EVA was used to estimate the crystallinity. Default values were used as input for the algorithm (DIFFRAC.EVA User Manual, 2014, Bruker AXS GmbH, Karlsruhe). All other parameters were determined using DIFFRAC.TOPAS. The entire diffraction pattern was simu lated using the crystal structures of hexagonal LaCoAlnOig, rhombohedral LaAI0₃, cubic C0AI2O4, hexagonal La(OH)3, cubic Co-doped LaAI03 and Corundum. During the simulation 29 parameters were refined to fit the simulated diffraction to the measured data.

The parameters are listed in the following Table 1.

Table 1

Parameters for refining

^* Using the March-Dollase model along the (1 1 0) direction. All crystal structures used were retrieved from the inorganic crystal structure database (ICSD) (ICSD, FIZ Karlsruhe (https://icsd.fiz-karlsruhe.de/)) or the Pearson‘s Crystal Data (PCD) (Pear- son‘s Crystal Data - Crystal Structure Database for Inorganic Compounds, Release 2016/2017, ASM International, Materials Park, Ohio, USA). The following Table 2 lists the reference num bers of the structures used.

Table 2

Numbers of structures used

The crystallite size values are those reported as Lvol-FWHM in DIFFRAC.TOPAS. To ensure reliable crystallite size values the geometry of the diffractometer was entered into the software to enable the calculation of the instrumental resolution based on the fundamental parameter approach (DIFFRAC.TOPAS User Manual, 2014, Bruker AXS GmbH, Karlsruhe). Scale factors were recomputed into mass percent values by DIFFRAC.TOPAS and have been reported.

Reference Example 3: Determination of temperature programmed reduction (TPR) profile

The reduction behavior of a molding was determined by temperature programmed reduction. 200 mg of a sample having particles with an average particle size between 0.2 and 0.4 mm were used. As a feed gas a stream of 5 volume-% hydrogen in Argon was used, whereby the feed rate was set to 50 ml/min. The temperature was increased during a measurement from room temperature up to 950°C with a heating rate of 5 K/min. The thermal conductivity detector (TCD) signal was recorded relative to the temperature to give the TPR profile. The TPR profiles of Examples 1-6, and Comparative Examples 1 are shown in Figures 2 and 3. The maxima in the recorded data related to the hydrogen consumption of a sample indicating reduction of Nickel.

Example 1 : Preparation of a mixed metal oxide comprising a Mg-rich crystalline phase NixMg_yO

18.0 g of Pural MG 30 was combined with 300 ml. deionized water under stirring (180 rpm) re sulting in a 6 weight-% suspension. 12.4 g nickel(ll) nitrate hexahydrate Ni(N03)2 6 H2O (CAS 13478-00-7, 98 weight-%) was combined with 410 ml. of deionized water to result in a 3 weight- % solution. Said nickel solution was then added to the Pural MG 30 mixture under stirring (250 rpm) and heated to 70 °C . 41.11 g of aqueous sodium carbonate solution (20 weight-%

Na₂C03 in water) was added slowly over about a 10 minute period to the nickel/Pural mixture until pH 8.5 of the resulting mixture was reached. The resulting mixture was then aged under reduced stirring (200rpm) at 70 °C for one hour under airflow (20 L/h). At the end of one hour the pH was measured to be 8.71. Elemental analysis of the mother liquor showed nitrate, Ni, Mg, Al, and Na. Microfilter used (Chromafil RC-45/25, 0.45 pm, Filter-0:25 mm).

The resulting solids were filtered and washed with water using an automated system that in sures that at least 50 L of water is used for said washing. Electrical conductivity after washing was measured (2 pS/cm, 24 L water in 2 h, 0 mg/L nitrate using nitrate test paper). The washed solids were transferred on a porcelain bowl and put into a dry cabinet at 110 °C under air overnight. Elemental analysis of the dried solids (nitrate, Ni, Mg, Al, and Na). The resulting dried solids weighed 21 .75 g. Subsequently, the dried solids were calcined in an annealing fur nace under air at 950 °C for 1 hour (heating up to 950 °C lasted 4 hours). The weight of the solids before calcining was 20.38 g and after calcining 13.53 g.

Example 2: Preparation of a mixed metal oxide comprising a Mg-rich crystalline phase Ni_xMg_yO

42.48 g nickel(ll) nitrate hexahydrate Ni(NC>3)2 6 H2O (CAS 13478-00-7, 98 weight-%) was combined with 713 mL of deionized water to result in a 14 weight-% solution. The nickel solu tion was then heated to 60 °C under stirring (250 rpm). 61.5 g of Pural MG 30 was then added to the stirring mixture. 113.3 g of aqueous sodium carbonate solution (20 weight-% Na2CC>3 in water) was added slowly over about a 30 minute period to the nickel/Pural mixture until pH 8.5 of the resulting mixture was reached. The resulting mixture was then aged under reduced stir ring (200rpm) at 60 °C for one hour under airflow (20 L/h).

The resulting solids were filtered and washed with water using an automated system that in sures that at least 50 L of water is used for said washing. Electrical conductivity after washing was measured (80.9 L water in 20 h, 0 mg/L nitrate using nitrate test paper). The washed sol ids were transferred on a porcelain bowl and put into a dry cabinet at 110 °C overnight. The resulting dried solids weighed 158 g. Subsequently, the dried solids were calcined in an anneal ing furnace under air at 950 °C for 1 hour (heating up to 950 °C lasted 4 hours).

Example 3: Preparation of a mixed metal oxide comprising a Mg-rich crystalline phase NixMg_yO

90.0 g of Pural MG 30 (Sasol) was added to 300 mL of deionized water under stiffing (180 rpm) to result in a 30.0 weight-% suspension. The suspension was then heated to 60 °C under stir ring (250 rpm). The measured pH of the mixture was 7.74. Elemental analysis of the mother liquor (25 mL) showed Al and Mg. 62.2 g nickel(ll) nitrate hexahydrate Nί(Nq3)_å 6 H2O (CAS 13478-00-7, 98 weight-%) was combined with 450 mL of deionized water to result in a 13.8 weight-% solution. The nitrate solution was then added to the Pural MG 30 mixture. 204 g of aqueous sodium carbonate solution (20 weight-% Na2C03 in water) was added quickly over about a 10 minute period to the nickel/Pural mixture until pH 8.5 of the resulting mixture was reached. The resulting mixture was then aged under reduced stirring (200 rpm) at 60 °C for one hour under airflow (20 L/h). At the end of one hour the pH measure at 8.41.

The resulting solids were filtered and washed with water using an automated system that in sures that at least 50 L of water is used for said washing. Electrical conductivity after washing was measured (<10 pS/cm, 108 L water in 22 h, 0 mg/L nitrate using nitrate test paper). Densi ty of the filtered solids was then determined to be 1.006 g/cm3. The washed solids were then transferred on a porcelain bowl and put into a dry cabinet at 110 °C under air overnight. The resulting dried solids weighed 100.4 g. Subsequently, the dried solids were calcined in an an nealing furnace under air at 950 °C for 1 hour (heating up to 950 °C lasted 4 hours). The weight of the solids after calcining was 66.9 g.

Example 4: Preparation of a mixed metal oxide comprising a Mg-rich crystalline phase Ni_xMg_yO

565.6 g of nickel(ll) nitrate hexahydrate Ni(NC>3)2 6 H2O aqueous solution (13.2 weight-%) was stirred at (200 rpm) and heated up within 20 minutes to 50 °C. Then, under slow stirring (100 rpm) 536 g of Pural MG 30 were added within 30 minutes to the said nickel solution. More than 1124 g of aqueous sodium carbonate solution (20 weight-% Na2CC>3 in water; pre-heated to 60°C) were slowly added within about 30 minutes to the Ni/Pural mixture until the pH value was 8.0. The suspension was then aged for one hour at 50 °C under stirring (100 rpm) and airflow (50 L/h). At the end of aging the pH measured at 8.0. Cooling was done at room temperature without air under stirring (100 rpm).

Elemental analysis of the mother liquor showed nitrate, Ni, Mg, Al, and Na. Microfilter used (Chromafil RC-45/25, 0.45 pm, Filter-0:25 mm).

The resulting solids were filtered and washed with water using an automated system that in sures that at least 50 L of water is used for said washing. Electrical conductivity after washing was measured (12 pS/cm, 1118.9 L water in 21 h, 0 mg/L nitrate using nitrate test paper). 1318.7 g of washed solids were recovered. 1313.1 g of washed solids were then put into a dry cabinet at 110 °C under air overnight. The resulting dried solids weighed 650.7 g. For pre calcination 52.9 g of dried solids were calcined in the annealing furnace under air at 400 °C for 1 hour (heating time 3K/min). The weight of the solids after pre- calcining was measured to be

39.6 g. For final calcination 23.8 g of pre-calcined solids were calcined in the annealing furnace under air at 950 °C for one hour (heating up to 950 °C lasted 4 hours). The weight of the solids after calcining was 15.6 g.

Comparative Example 1 : Preparation of a mixed metal oxide comprising a Ni-rich crystalline phase Ni_aMgt>0 and a Mg-rich crystalline phase Ni_xMg_yO 18.0 g of Pural MG 30 was combined with 300 imL deionized water under stirring (180 rpm) re sulting in a 6 weight-% suspension. 12.3 g nickel(ll) nitrate hexahydrate Ni(NC>3)2 6 H2O (CAS 13478-00-7, 98 weight-%) was combined with 410 ml. of deionized water to result in a 3 weight- % solution. Pural MG 30 mixture which was then heated to 70 °C under stirring (250 rpm). The nickel solution and 41.2 g of aqueous sodium carbonate solution (20 weight-% Na2CC>3 in water) were added at the same time slowly to the Pural MG 30 mixture over about a 30 minute period until pH 8.5 of the resulting mixture was reached. The resulting mixture was then aged under reduced stirring (200rpm) at 70 °C for one hour under airflow (20 L/h). At the end of one hour the pH was measured to be 8.71. Elemental analysis of the mother liquor (showed nitrate, Ni, Mg, Al, and Na. Microfilter used (Chromafil RC-45/25, 0.45 pm, Filter-0:25 mm).

The resulting solids were filtered and washed with water using an automated system that in sures that at least 50 L of water is used for said washing. Electrical conductivity after washing was measured (4 pS/cm, 42 L water in 1 h, 0 mg/L nitrate using nitrate test paper). The washed solids were transferred on a porcelain bowl and put into a dry cabinet at 110 °C over night. Elemental analysis of the dried solids (nitrate, Ni, Mg, Al, and Na). The resulting dried solids weighed 21.99 g. Subsequently, the dried solids were calcined in an annealing furnace under air at 950 °C for 1 hour (heating up to 950 °C lasted 4 hours). The weight of the solids before calcining was 18.99 g and after calcining 12.85 g.

Comparative Example 2: Preparation of a mixed metal oxide comprising a Ni-rich crystalline phase N Mg_bO and a Mg-rich crystalline phase Ni_xMg_yO

18.0 g of Pural MG 30 was combined with 300 mL deionized water under stirring (180 rpm) re sulting in a 6 weight-% suspension. 12.3 g nickel(ll) nitrate hexahydrate Ni(N03)2 6 H₂0 (CAS 13478-00-7, 98 weight-%) was combined with 410 mL of deionized water to result in a 3 weight- % solution. Pural MG 30 mixture which was then heated to 50 °C under stirring (250 rpm). The nickel solution and 34.7 g of aqueous sodium carbonate solution (20 weight-% Na₂C03 in water) were added at the same time slowly to the Pural MG 30 mixture over about a 30 minute period until pH 8.5 of the resulting mixture was reached. The resulting mixture was then aged under reduced stirring (200rpm) at 50 °C for one hour under airflow (20 L/h). At the end of one hour the pH was measured to be 8.59. Elemental analysis of the mother liquor showed nitrate, Ni, Mg, Al, and Na. Microfilter used (Chromafil RC-45/25, 0.45 pm, Filter-0:25 mm).

The resulting solids were filtered and washed with water using an automated system that in sures that at least 50 L of water is used for said washing. Electrical conductivity after washing was measured (16 pS/cm, 46 L water in 2 h, 0 mg/L nitrate using nitrate test paper). The washed solids were transferred on a porcelain bowl and put into a dry cabinet at 110 °C under air overnight. Elemental analysis of the dried solids (nitrate, Ni, Mg, Al, and Na). The resulting dried solids weighed 21 .10 g. Subsequently, the dried solids were calcined in an annealing fur- nace under air at 950 °C for 1 hour (heating up to 950 °C lasted 4 hours). The weight of the solids before calcining was 17.80 g and after calcining 12.0 g.

Comparative Example 3: Preparation of a mixed metal oxide comprising a Ni-rich crystalline phase Ni_aMg_t>0 and a Mg-rich crystalline phase Ni_xMg_yO

18.0 g of Pural MG 30 was combined with 300 ml. deionized water under stirring (180 rpm) re sulting in a 6 weight-% suspension. 12.3 g nickel(ll) nitrate hexahydrate Ni(N03)2 6 H 0 (CAS 13478-00-7, 98 weight-%) was combined with 410 ml. of deionized water to result in a 3 weight- % solution. Pural MG 30 mixture which was then heated to 50 °C under stirring (250 rpm). The nickel solution and 34.8 g of aqueous sodium carbonate solution (20 weight-% Na₂CC>3 in water) were added at the same time slowly to the Pural MG 30 mixture over about a 60 minute period until pH 8.5 of the resulting mixture was reached. The resulting mixture was then aged under reduced stirring (200rpm) at 50 °C for one hour under airflow (20 L/h). At the end of one hour the pH was measured to be 8.61. Elemental analysis of the mother liquor showed nitrate, Ni, Mg, Al, and Na. Microfilter used (Chromafil RC-45/25, 0.45 pm, Filter-0:25 mm).

The resulting solids were filtered and washed with water using an automated system that in sures that at least 50 L of water is used for said washing. Electrical conductivity after washing was measured (8 pS/cm, 46.5 L water in 3 h, 0 mg/L nitrate using nitrate test paper). The washed solids weighed 49.2 g. The washed solids were transferred on a porcelain bowl and put into a dry cabinet at 110 °C under air overnight. Elemental analysis of the dried solids (ni trate, Ni, Mg, Al, and Na). Subsequently, the dried solids were calcined in an annealing furnace under air at 950 °C for 1 hour (heating up to 950 °C lasted 4 hours).

Table 1: Elemental composition of examples 1-4 and comparative examples 1-3.

Table 2: Crystalline composition for Phase 1 of examples 1-4 and comparative examples 1-3.

Table 3: Crystalline composition for Phase 2 of examples 1-4 and comparative examples 1-3.

Table 4: XRD for examples 1-4 and comparative examples 1-3.

Comparative Example 4: Preparation of a molding according to the prior art

Example E1 of WO 2013/068905 A1 was repeated.

The nickel content of the calcined moldings was 14.7 weight-%, the magnesium content 14.2 weight-% and the aluminum content 30.0 weight-%, calculated as the elements, respectively.

The calcined moldings comprised 79 weight-% of a crystalline phase MgAI₂0 having an aver age particle size of 8 nm and 21 weight-% of a crystalline phase Ni_aMg_bO, whereby a was 0.52 and b was 0.48, having an average particle size of 5.5 nm. The lattice parameter a of the crys talline phase Ni_aMg_bO was determined as being 4.1933. In the TPR profile, a single peak was found having a maximum at about 775 °C. Further, the resulting product showed a total hydro gen consumption in the TPR profile below 600 °C of 0 pmol H₂/g catalyst, and above 600 °C of 2018 pmol H₂/g catalyst.

Description of the Figures

Figure 1 : shows the change in pH of the reaction mixture in Example 1 upon addition of the aqueous sodium carbonate solution and thereafter. In the figure, the pH values are ploted along the ordinate and the time in minutes is plotted along the abscissa.

Figure 2: shows the change in pH of the reaction mixture in Comparative Example 1 upon the simultaneous addition of the nickel solution and the aqueous sodium carbonate so lution. In the figure, the pH values are ploted along the ordinate and the time in minutes is plotted along the abscissa shows Figure 3: shows the change in pH of the reaction mixture in Comparative Example 2 upon the simultaneous addition of the nickel solution and the aqueous sodium carbonate so lution. In the figure, the pH values are ploted along the ordinate and the time in minutes is plotted along the abscissa.

Figure 4: shows the change in pH of the reaction mixture in Comparative Example 3 upon the simultaneous addition of the nickel solution and the aqueous sodium carbonate so lution. In the figure, the pH values are ploted along the ordinate and the time in minutes is plotted along the abscissa.

Figure 5: shows the TPR profile for Examples 1 , 2, and 3 as well as for Comparative Exam ple 4. The thermal conductivity detector (TCD) signal was recorded relative to the temperature to give the TPR profile. Thus, the TCD signal is given in arbitrary units on the ordinate and the temperature is shown on the abscissa in °C.

Figure 6: shows the TPR profiles for Comparative Examples 1 , 2 and 3. The thermal conduc tivity detector (TCD) signal was recorded relative to the temperature to give the TPR profile. Thus, the TCD signal is given in arbitrary units on the ordinate and the tem perature is shown on the abscissa in °C.

Cited Literature:

- WO 2013/068905 A1

- CN 107890870 A

- US20180141028 A1

- US 2010/0213417 A1

- CN 108704647 A

- CN 106512999 A

- US20120190539 A1

- JP2017029970 A

- WO2010035430 A1

Claims

(2) heating the mixture prepared in (1);

(4) optionally aging the mixture obtained in (3);

(5) isolating the solids from the mixture obtained in (3) or (4);

(6) optionally washing the solids obtained in (5);

(7) drying the solids obtained in (5) or (6); and

(8) calcining the solids obtained in (5), (6), or (7).

2. The process of claim 1, wherein the layered double hydroxide compound comprises posi tively charged main metal layers of the formula (I)

[MI-_XN_X(OH)₂]^x+ (I) wherein M is a divalent element and N is a trivalent element, wherein 0.2 < x < 0.33, and wherein the layered double hydroxide compound comprises intercalating anions between the main metal layers.

3. The process of claim 2, wherein M comprises one or more elements selected from the group consisting of Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn, including mixtures of two or more thereof.

4. The process of claim 2 or 3, wherein N comprises one or more elements selected from the group consisting of Al, B, In, and Ga, including mixtures of two or more thereof.

5. The process of any of claims 2 to 4, wherein the intercalating anions are selected from the group consisting of chloride, bromide, nitrate, carbonate, and sulfate, including mixtures of two or more thereof.

6. The process of any of claims 1 to 5, wherein the layered double hydroxide compounds comprises hydrotalcite. 7. The process of any of claims 1 to 6, wherein the one or more transition metals T is select ed from the group consisting of Fe, Co, Ni, Pt, Rh, and Pd, including mixtures of two or more thereof.

8. A mixed metal oxide obtainable or obtained according to the process of any of claims 1 to 7.

9. The mixed metal oxide of claim 8, wherein the mixed metal oxide comprises O, Mg, and Ni, wherein the mixed metal oxide comprises a crystalline phase Ni_xMg_yO, wherein the sum of x and y is 1 , and wherein y is greater than 0.52.

10. The mixed metal oxide of claim 8 or 9, wherein the mixed metal oxide further comprises a metal M, wherein M is selected from the group consisting of Al, Ga, In, Si, Ge, Sn, Ti and Zr.

11. The mixed metal oxide of claim 10, wherein the metal M is Al, and wherein the mixed metal oxide further comprises a crystalline phase MgA O^

12. The mixed metal oxide of any of claims 8 to 11 , wherein the lattice parameter a of the crystalline phase Ni_xMg_yO is in the range of from 4.191 to 4.208 Angstrom.

13. The mixed metal oxide of any of claims 8 to 12, wherein the mixed metal oxide exhibits a temperature programmed reduction profile, wherein the temperature programmed reduc tion profile comprises a first peak having a maximum in the range of from 700 to 840 °C.

14. A method for reforming one or more hydrocarbons, to a synthesis gas comprising hydro gen and carbon monoxide, the method comprising

(a) providing a reactor comprising a reaction zone which comprises the mixed metal ox ide according to any one of claims 8 to 13;

15. Use of the mixed metal oxide according to any of claims 8 to 13 as a catalytically active material, as a catalyst component or as a catalyst.