WO2024057336A1

WO2024057336A1 - A catalyst composition and processes thereof

Info

Publication number: WO2024057336A1
Application number: PCT/IN2023/050858
Authority: WO
Inventors: Sebastian Chirambatte PETER; Devender GOUD
Original assignee: Jawaharlal Nehru Centre For Advanced Scientific Research
Priority date: 2022-09-13
Filing date: 2023-09-13
Publication date: 2024-03-21

Abstract

The present disclosure provides a composition comprising: (a) 1 to 20% (w/w) indium; (b) 40 to 60% (w/w) of iron oxide; (c) 1 to 5% (w/w) of potassium; and (d) 35 to 40% (w/w) alumina. The present disclosure further provides a convenient process for 5 preparing the composition. The composition of the present disclosure is a hydrogenation catalyst. Furthermore, the present disclosure provides a process for hydrogenation of carbon dioxide to higher alcohols.

Description

A CATALYST COMPOSITION AND PROCESSES THEREOF

TECHNICAL FIELD

[0001] The present disclosure relates to a composition and in particular the present disclosure relates to a catalyst composition for hydrogenation process. The present disclosure further relates to a process of hydrogenation of carbon dioxide to obtain higher alcohols.

BACKGROUND OF INVENTION

[0002] Conventionally, higher alcohols (HA) are largely produced by the fermentation of sugars and hydration of petroleum-derived alkenes. However, the low productivity and a huge dependence on agriculture for the fermentation process, use of non-renewable petroleum derived HAs, etc. impede these conventional processes from being sustainable and economical. Thus, the use of abundantly available CO2 seems to be an appealing substitute for the sustainable production of HAs. The conversion of CO2 to Cl molecules especially methanol has witnessed exceptional progress. However, direct conversion of CO2 to C2 alcohols remains elusive because of the lack of stable and efficient catalysts that can promote controlled C-C coupling towards HA with high activity and stability. In addition, the synthesis of C2+ alcohols is more arduous than C2⁺ hydrocarbons because having precise control over the C-C coupling is very crucial for the synthesis of higher alcohols. The alcohols produced follow the Anderson-Schulz-Flory (ASF) distribution rule because the methanol synthesis predominates the subsequent CO conversion to hydrocarbons and diminishes the synthesis of C2+ alcohols.

[0003] Numerous classes of catalysts are widely explored for the synthesis of HA. They encompass i) modified Fischer-Tropsch synthesis (FTS) catalysts (Fe, Ni, Co-based), (ii) Rh-based catalysts, (iii) modified methanol synthesis catalysts (Cu based), and (iv) M02C- and M0S2- based catalysts. However, achieving higher selectivity to C2+ alcohols is still an unmet challenge, which requires proper control between the carbon chain growth and the non-dissociative insertion of CO.

[0004] Iron-based catalysts are well explored for the Fischer-Tropsch Synthesis (FTS) as well as to produce olefins from CO2. The CO2 hydrogenation can be considered as altered Fischer-Tropsch Synthesis (FTS). Generally, CO2 hydrogenation proceeds via two steps on iron-based catalysts. The first step being CO2 reduction to CO by reverse water gas shift reaction (RWGS) and the second step involves the transformation of CO to hydrocarbons through FTS. It is observed that RWGS happens extensively on the surface of the iron oxide phase whereas the FTS is favored on the iron carbide. The lack of iron carbide formation through the carburization of catalyst by CO2/H2 at reaction conditions will significantly reduce the FTS and promotes only RWGS. The addition of promoters, such as K and Na on iron oxide catalysts significantly alters its FTS activity by increasing CO2 adsorption and enhancing the iron carbide formation. In particular, the introduction of K enhanced production of olefin and higher hydrocarbon. However, it is extremely difficult to produce HA from CO2 by suppressing olefins. On the other hand, the reaction must not stop with RWGS. Thus there is a requirement for the selective reaction sequence and specific catalysts to promote the reaction towards production of HA from CO2.

[0005] Various catalyst systems such as noble metal-based catalysts, such as Pd2Cu-NPs- P25, Pd/Fe3O4, RhFeLi/TiO2 and Pt/Co3O4, were reported to activate CO2 as well as facilitate the C-C coupling leading to enhanced selectivity to HA. However, the use of expensive noble metals hamper their commercialization. Also, non-noble metal-based catalysts such as Cs-promoted Cu-Fe-Zn, bifunctional Ir-h Os, Co-Al LDH and Coo.52Nio.4₈A10_x have been explored for HA synthesis. Nevertheless, there is a dire need for catalysts for hydrogenation of carbon dioxide involving low cost metals yet efficiently catalyse the hydrogenation process, in particular, to yield higher alcohols.

SUMMARY OF THE INVENTION

[0006] In an aspect of the present disclosure, there is provided a composition comprising: a) 1 to 20% (w/w) indium (In); b) 40 to 60% (w/w) of iron oxide (Fe2O3); c) 1 to 5% (w/w) of potassium (K); and d) 35 to 40% (w/w) alumina (AI2O3).

[0007] In another aspect of the present disclosure, there is provided a process for preparing the composition comprising: a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3, the process comprising: (i) mixing a salt of potassium with alumina to obtain K-promoted alumina; (ii) contacting an iron salt and an indium salt in presence of a solvent to obtain a first solution; (iii) adding the K-promoted alumina to the first solution to obtain a mixture; and (iv) calcining the mixture at a temperature in a range of 350 to 450°C to obtain the composition.

[0008] In one another aspect of the present disclosure, there is provided a process for hydrogenation of carbon dioxide , the process comprising: a) reducing the composition as disclosed herein at a temperature in a range of 350 to 450°C to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol, wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof.

[0009] These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

[0010] In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure wherein:

[0011] Figure 1 depicts PXRD (powder x-ray diffraction) pattern of different weight percentages of indium oxide loaded samples ranging from 0 to 20% (a) unpromoted (b) with K promotion, (c) TEM (transmission electron microscopic) images and (d) HRTEM (high resolution TEM) analysis of In_2_Fe/K-AhO3 before the reaction showed a d spacing of 0.201 nm corresponding to 211 plane of Fe2O3, and (e) the after reaction sample showed the presence of 400 plane of FesCU, in accordance with an embodiment of the present disclosure. [0012] Figure 2 (a, b, cl) depicts SEM (scanning electron microscopic) images of In lO-Fe/K-AhCh before reaction; (c2) depicts the individual elemental mapping for Fe, In, O, Al and K corresponding to cl; d) and e) the ED AX (energy dispersive x-ray) analysis of the same sample, in accordance with an embodiment of the present disclosure. [0013] Figure 3 (a, b, cl) depicts SEM images of In 20_Fe/K-AhO3 before reaction; (c2) depicts the individual elemental mapping for Fe, In, O, Al and K corresponding to cl; d) and e) the ED AX analysis of the same sample, in accordance with an embodiment of the present disclosure.

[0014] Figure 4 (a, b, cl) depicts SEM images of In 10_Fe/K-AhO3 after reaction; (c2) depicts the individual elemental mapping for Fe, In, O, Al and K corresponding to cl; d) and e) the ED AX analysis of the same sample, in accordance with an embodiment of the present disclosure.

[0015] Figure 5 (a, bl, b2, cl) depicts SEM images of In 20_Fe/K-AhO3 after reaction; (c2) depicts the individual elemental mapping for Fe, In, O, Al and K corresponding to c; d) and e) the ED AX analysis of the same sample, in accordance with an embodiment of the present disclosure.

[0016] Figure 6 depicts CO2 conversion and product distribution with respect to catalyst Fe2O3 with different In substitution (a and b); 2% K promotion at different In substituted samples (c and d); and different amount of K promoted on In_2_Fe/AhO3 sample(e and f), in accordance with an embodiment of the present disclosure.

[0017] Figure 7 depicts (a, b) H2 TPR (Temperature Programmed Reduction) profiles and (c, d) CO2 TPD (Temperature Programmed Desorption) profiles of un-promoted and K promoted samples with different In substitution at Fe2O3, in accordance with an embodiment of the present disclosure.

[0018] Figure 8 depicts (a) the variation of I112O3 percentage; (b) variation of I112O3 percentage in K promoted samples, (c) variation of K percentageK promoted samples with respect to yield % and strain, in accordance with an embodiment of the present disclosure.

[0019] Figure 9 depicts PXRD of different I112O3 % substituted samples after the reaction (Tested at 300 °C, 20 bar and WHSV of 4000), in accordance with an embodiment of the present disclosure. [0020] Figure 10 depicts PXRD of different I112O3 % substituted K-promoted alumina containing samples after the reaction, in accordance with an embodiment of the present disclosure.

[0021] Figure 11 depicts PXRD of different I112O3 % substituted K-promoted alumina containing samples with varying potassium weight percentage after the reaction, in accordance with an embodiment of the present disclosure.

[0022] Figure 12 depicts in-situ DRIFTS spectra at ambient pressure with variation of the temperature from 30 to 300 °C with CChiEh of 1:3 of different samples a) Fe/K- AI2O3, b) In_2_Fe/K-Al₂O₃, c) In_5_Fe/K-Al₂O₃, and d) In_20_Fe/K-Al₂O₃, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0023] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.

Definitions

[0024] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0025] The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

[0026] The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. [0027] Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.

[0028] The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.

[0029] In the structural formulae given herein and throughout the present disclosure, the following terms have been indicated meaning, unless specifically stated otherwise.

[0030] The term “at least one” is used to mean one or more and thus includes individual components as well as mixtures/combinations.

[0031] The term “composition”, “catalyst”, and “catalyst composition”, used interchangeably herein, refers to a composition capable of catalysing a hydrogenation process, for eg: hydrogenation of carbon dioxide. It refers to a composition comprising a) In (indium); b) Fe2O3 (iron oxide); c) K (Potassium); and d) AI2O3 (alumina). In an embodiment, it refers to a composition comprising a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3.

[0032] The term “w/w” refers to weight by total weight, for example, 1 to 20% (w/w) In refers to 1 to 20% by weight of indium with respect to the total weight of the composition. [0033] The term “strain induced phase” refers to the phase of a compound wherein a strain is induced to the compound via the substitution with one or more types of atoms leading to expansion of lattice parameters. The induced strain of a compound or composition can be calculated from the XRD patterns using Williamson-Hall method. In an aspect of the present disclosure, the strain in the composition is in a range of 0.002 to 0.004.

[0034] The term “K-promoted sample” refers to a composition comprising a) In; b) Fe2O3; c) K; and d) AI2O3 In an embodiment, it refers to a composition comprising a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3, of the composition. In some embodiment, it refers to a composition wherein indium and iron oxide are supported on potassium promoted alumina. The term “unpromoted sample” refers to a composition comprising only indium, iron oxide supported on alumina. [0035] The term “C2 to Cs alkanol” refers to an alcohol comprising 2 to 8 carbon atoms having one or more hydroxy groups. Alkanol of the present disclosure is selected from ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, their isomers, or combinations thereof.

[0036] A term once described, the same meaning applies to it, throughout the disclosure. [0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0038] As discussed in the background, the conversion of CO2 to higher alcohols (HA) and higher hydrocarbons (HC) has a greater advantage compared to Cl products because of their high energy density and wide range of applications. Despite the immense potential of these chemicals, not much of materials are available to obtain these products and thus there is a constant search for a catalyst for the conversion of carbon dioxide in particular a low cost catalyst for the conversion of carbon dioxide to higher alcohols. Accordingly, the present disclosure provides iron oxide based catalyst to enhance the conversion of CO2 to HA. The present disclosure provides a strain induced iron-based catalyst with the inclusion of indium to facilitate the selective conversion of CO2 to HA. The introduction of strain upon the substitution with In and further promotion with K- incorporated alumina in the catalyst composition is favourable for obtaining the desired product. Thus the catalyst composition of the present disclosure comprises indium with iron oxide supported on potassium promoted alumina. The present disclosure also provides a process for preparing the composition. The present disclosure further discloses an optimized process for the hydrogenation of carbon dioxide to higher alcohol using the composition. The process of the present disclosure also provides a higher selectivity and conversion of carbon dioxide to higher alcohols.

[0039] In an embodiment of the present disclosure, there is provided a composition comprising: a) 1 to 20% (w/w) indium(In); b) 40 to 60% (w/w) of iron oxide(Fe2O3); c) 1 to 5% (w/w) of potassium(K); and d) 35 to 40% (w/w) alumina/ AI2O3). [0040] In an embodiment of the present disclosure, there is provided a composition comprising: a) 1 to 20% (w/w) of In; b) 40 to 60% (w/w) of Fe2Os; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) of AI2O3. In another embodiment of the present disclosure, the composition comprises: a) 2 to 20% (w/w) In; b) 40 to 58% (w/w) of Fe2Os; c) 1 to 5% (w/w) of K; and d) 35 to 39% (w/w) of AI2O3. In yet another embodiment of the present disclosure, the composition comprises: a) 2%, 5%, 10% or 20% (w/w) of In; b) 40 to 58% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 39% (w/w) of AI2O3. In still another embodiment of the present disclosure, the composition comprises: a) 2%, 5%, 10% or 20% (w/w) of In; b) 40 to 58% (w/w) of Fe2O3; c) 1%, 2%, 3.5% or 5% (w/w) of K; and d) 35 to 39% (w/w) of AI2O3. In more embodiments of the present disclosure, the composition comprises: 2%, 5%, 10% or 20% (w/w) of In. In further embodiments of the present disclosure, the composition comprises: 1%, 2%, 3.5% or 5% (w/w) of K. In other embodiments of the present disclosure, the composition comprises: 3.5% (w/w) of K.

[0041] In an embodiment of the present disclosure, there is provided a composition comprising: a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3, wherein potassium is incorporated into alumina to obtain K-promoted alumina; and indium and iron oxide are impregnated on to K-promoted alumina.

[0042] In an embodiment of the present disclosure, there is provided a hydrogenation catalyst composition comprising: a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3.

[0043] In an embodiment of the present disclosure, there is provided a composition as disclosed herein, wherein the composition has a strain induced phase of Fe2O3. In another embodiment of the present disclosure, wherein the strain in the composition is in a range of 0.002 to 0.004. In another embodiment of the present disclosure, wherein the strain in the composition is in a range of 0.002 to 0.0032.

[0044] In an embodiment of the present disclosure, there is provided a process for preparing the composition comprising: a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3, the process comprising: (i) mixing a salt of potassium with alumina to obtain K-promoted alumina; (ii) contacting an iron salt and an indium salt in presence of a solvent to obtain a first solution; (iii) adding the K-promoted alumina to the first solution to obtain a mixture; and (iv) calcining the mixture to obtain the composition.

[0045] In an embodiment of the present disclosure, there is provided a process for preparing the composition as disclosed herein, wherein the salt of potassium is an aqueous solution of a salt selected from potassium nitrate, potassium chloride, or combinations thereof. In another embodiment of the present disclosure, the salt of potassium is an aqueous solution of potassium nitrate.

[0046] In an embodiment of the present disclosure, there is provided a process for preparing the composition as disclosed herein, wherein mixing a salt of potassium with alumina is carried out under stirring followed by drying at a temperature in a range of 100 to 160°C. In another embodiment of the present disclosure, the drying is carried out at a temperature in a range of 120 to 155 °C. In yet another embodiment of the present disclosure, the drying is carried out at a temperature in a range of 145 to 150°C. In still another embodiment of the present disclosure, the drying is carried out at a temperature of 150°C.

[0047] In an embodiment of the present disclosure, there is provided a process for preparing the composition as disclosed herein, wherein the solvent is water.

[0048] In an embodiment of the present disclosure, there is provided a process for preparing the composition as disclosed herein, wherein the iron salt is selected from iron nitrate, iron chloride, or combinations thereof; and the indium salt is selected from indium nitrate, indium chloride, or combinations thereof. In another embodiment of the present disclosure, the iron salt is iron nitrate; and the indium salt is indium nitrate.

[0049] In an embodiment of the present disclosure, there is provided a process for preparing the composition as disclosed herein, wherein adding the K-promoted alumina to the first solution is carried out under stirring followed by heating at a temperature in a range of 100 to 160°C. In another embodiment of the present disclosure, the heating is carried out at a temperature in a range of 120 to 155°C. In yet another embodiment of the present disclosure, the heating is carried out at a temperature in a range of 145 to 150°C. In still another embodiment of the present disclosure, the heating is carried out at a temperature of 150°C. [0050] In an embodiment of the present disclosure, there is provided a process for preparing the composition as disclosed herein, wherein calcining is carried out at a temperature in a range of 350 to 450°C. In another embodiment of the present disclosure, calcining is carried out at a temperature in a range of 380 to 420°C. In yet another embodiment of the present disclosure, calcining is carried out at a temperature in a range of 390 to 410°C. In still another embodiment of the present disclosure, calcining is carried out at a temperature of 400°C.

[0051] In an embodiment of the present disclosure, there is provided a process for preparing the composition comprising: a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2Os; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3, the process comprising: (i) mixing an aqueous solution of a salt selected from potassium nitrate, potassium chloride, or combinations thereof, with alumina under stirring followed by drying at a temperature in a range of 100 to 160°C to obtain K-promoted alumina; (ii) contacting an iron salt selected from iron nitrate, iron chloride, or combinations thereof, and an indium salt selected from indium nitrate, indium chloride, or combinations thereof, in presence of water to obtain a first solution; (iii) adding the K-promoted alumina to the first solution under stirring followed by heating at a temperature in a range of 100 to 160°C to obtain a mixture; and (iv) calcining the mixture at a temperature in a range of 350 to 450°C to obtain the composition.

[0052] In an embodiment of the present disclosure, there is provided a process for preparing the composition comprising: a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2Os; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3, the process comprising: (i) mixing an aqueous solution of potassium nitrate with alumina under stirring followed by drying at a temperature in a range of 100 to 160°C to obtain K-promoted alumina; (ii) contacting iron nitrate, and indium nitrate in presence of water to obtain a first solution; (iii) adding the K-promoted alumina to the first solution under stirring followed by heating at a temperature in a range of 100 to 160°C to obtain a mixture; and (iv) calcining the mixture at a temperature in a range of 350 to 450°C to obtain the composition.

[0053] In an embodiment of the present disclosure, there is provided a process for preparing the composition comprising: a) 1 to 20% (w/w) In; b) 40 to 60% (w/w) of Fe2O3; c) 1 to 5% (w/w) of K; and d) 35 to 40% (w/w) AI2O3, the process comprising: (i) mixing an aqueous solution of potassium nitrate with alumina under stirring followed by drying at a temperature in a range of 100 to 160°C to obtain K-promoted alumina; (ii) contacting iron nitrate, and indium nitrate in presence of water to obtain a first solution; (iii) adding the K-promoted alumina to the first solution under stirring followed by heating at a temperature in a range of 100 to 160°C to obtain a mixture; and (iv) calcining the mixture at a temperature in a range of 350 to 450°C to obtain the composition, wherein the composition has a strain induced phase of Fe2O3.

[0054] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide , the process comprising: a) reducing the composition as disclosed herein at a temperature in a range of 350 to 450°C to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol; wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof. In another embodiment of the present disclosure, the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 1:1 to 3:1. In another embodiment of the present disclosure, the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio of 3:1.

[0055] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide as disclosed herein, wherein the composition is diluted with a support in ratio of 1:1 to 1:6. In another embodiment of the present disclosure, the support is alumina. In one another embodiment of the present disclosure, the composition is diluted with alumina in a ratio of 1:4.

[0056] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide, the process comprising: a) diluting the composition as disclosed herein with a support and reducing the composition at a temperature in a range of 350 to 450°C to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol, wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof, the composition is diluted with a support in ratio of 1:1 to 1:6.

[0057] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide as disclosed herein, wherein reducing the composition is carried out in presence of hydrogen gas and optionally nitrogen gas.

[0058] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide, the process comprising: a) reducing the composition as disclosed herein at a temperature in a range of 350 to 450°C in presence of hydrogen gas and optionally nitrogen gas to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol; wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof.

[0059] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide as disclosed herein, wherein the hydrogen (H2) gas and the nitrogen gas (N2) are taken in a flow rate of 50 to 100 mL min ¹ of H2 and 10 to 30 mL min ¹ of N2.

[0060] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide, the process comprising: a) reducing the composition as disclosed herein at a temperature in a range of 350 to 450°C in presence of hydrogen gas and optionally nitrogen gas to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol, wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof, wherein the hydrogen (H2) gas and the nitrogen gas (N2) are taken in a flow rate of 50 to 100 mL min ¹ of H2 and 10 to 30 mL min ¹ of N2.

[0061] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide, the process comprising: a) diluting the composition as disclosed herein with a support and reducing the composition at a temperature in a range of 350 to 450°C in presence of hydrogen gas and optionally nitrogen gas to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol, wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof, wherein the composition is diluted with a support in ratio of 1:1 to 1:6, the hydrogen (H2) gas and the nitrogen gas (N2) are taken in a flow rate of 50 to 100 mL min ¹ of H2 and 10 to 30 mL min^-1 of N2.

[0062] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide as disclosed herein, wherein contacting the activated catalyst with a feed gas is carried out at a weight hourly space velocity (WHSV) in a range of 3000 to 5000 mLgcat^-1 h^-1. In another embodiment of the present disclosure contacting the activated catalyst with a feed gas is carried out at a weight hourly space velocity (WHSV) in a range of 3500 to 4500 mLgcat^-1 h^-1. In yet another embodiment of the present disclosure contacting the activated catalyst with a feed gas is carried out at a weight hourly space velocity (WHSV) in a range of 3800 to 4200 mLg cat ^-1 h ’ . In still another embodiment of the present disclosure contacting the activated catalyst with a feed gas is carried out at a weight hourly space velocity (WHSV) of 4000 mLgcat^-1 h^-1 [0063] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide , the process comprising: a) diluting the composition as disclosed herein with a support and reducing the composition at a temperature in a range of 350 to 450°C in presence of hydrogen gas and optionally nitrogen gas to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a weight hourly space velocity (WHSV) in a range of 3000 to 5000 mLgcat^-1 h^-1 at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol; wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof, wherein the composition is diluted with a support in ratio of 1:1 to 1:6, the hydrogen (H2) gas and the nitrogen gas (N2) are taken in a flow rate of 50 to 100 mL min ¹ of H2 and 10 to 30 mL min ¹ of N2. [0064] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide as disclosed herein, wherein hydrogenation of carbon dioxide to a higher alcohol is in a selectivity range of 35 to 50% and conversion % of carbon dioxide is in a range of 30 to 40%.

[0065] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide as disclosed herein, wherein the higher alcohol is obtained in a yield range of 10 to 25%.

[0066] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide as disclosed herein, wherein the process further yields hydrocarbons, lower alcohol, carbon monoxide, or combinations thereof.

[0067] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide to a higher alcohol in a selectivity range of 35 to 50% and conversion % of carbon dioxide is in a range of 30 to 40%, the process comprising: a) reducing the composition as disclosed herein at a temperature in a range of 350 to 450°C to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol; wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof.

[0068] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide, the process comprising: a) reducing the composition as disclosed herein at a temperature in a range of 350 to 450°C to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain a higher alcohol; wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5; the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof, and the higher alcohol is obtained in a yield range of 10 to 25%.

[0069] In an embodiment of the present disclosure, there is provided a process for hydrogenation of carbon dioxide , the process comprising: a) reducing the composition as disclosed herein at a temperature in a range of 350 to 450°C to obtain an activated catalyst; b) contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c) condensing the hydrogenated gas to obtain higher alcohol, hydrocarbons, lower alcohol, carbon monoxide, or combinations thereof; wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio range of 5:1 to 1:5.

[0070] In an embodiment of the present disclosure, there is provided use of the composition as disclosed herein for hydrogenation of carbon dioxide .

[0071] In an embodiment of the present disclosure, there is provided use of the composition as disclosed herein for hydrogenation of carbon dioxide to a higher alcohol selected from one or more of C2 to Cs alkanol.

[0072] In an embodiment of the present disclosure, there is provided use of the composition as disclosed herein for hydrogenation of carbon dioxide to a product selected from hydrocarbons, lower alcohol, carbon monoxide, or combinations thereof.

[0073] In an embodiment of the present disclosure, there is provided use of the composition as disclosed herein for hydrogenation of carbon dioxide to a higher alcohol hydrocarbons, lower alcohol, carbon monoxide, or combinations thereof; and the higher alcohol is selected from one or more of C2 to Cs alkanol.

[0074] Although the subject matter has been described in considerable detail with reference to certain examples and implementations thereof, other implementations are possible.

EXAMPLES

[0075] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply.

Materials and Methods

[0076] For the purpose of the present disclosure, the following materials were used for preparing the composition and for hydrogenation of carbon dioxide : Potassium nitrate

Alumina

Iron nitrate

Indium nitrate

Hydrogen gas

Carbon dioxide gas

Nitrogen gas

Characterization techinques

[0077] The as-prepared composition of the present disclosure was characterized using the following techniques and methods.

[0078] Powder X-ray diffraction (PXRD) Analysis: PXRD was collected on Rigaku X-ray diffractometer with Cu Ka radiation at 45 kV and 40 mA. The features of the PXRD patterns were compared with simulated pattern from Pearson Database.

[0079] Temperature Programmed Reduction (TPR): The reduction properties of all the catalyst composition of the present disclosure were tested by TPR analysis using the Altamira AMI-300 Lite instrument. In a typical procedure, approximately 50 mg of sample was taken in a U shaped TPR cell and it was reduced in a stream of 10% H2 in Argon with a ramp rate of 10 °C min ¹ up to 900 °C followed by a hold time of 30 min. The TCD (thermal conductivity detection) response was calibrated after every TPR analysis and the amount of hydrogen consumed for the reduction of the samples was calculated.

[0080] CO2 Temperature Programmed Desorption (TPD): CO2 TPD analysis was performed with 10% CO2 in helium Altamira AMI-300 Lite instrument. In a typical procedure around 100 mg of sample was taken in the TPD cell and prior to the analysis the sample was pretreated at 400 °C for 4h with a ramp rate of 10°C min ¹ with 10% H2. Then the sample was allowed to cool down to 50 °C, and saturated with CChby passing a mixture containing 5 ml min ¹ CO2 and 45 ml/min helium for 60 minutes. It was post flushed with helium to remove any physisorbed CO2. Then TPD analysis was started from 50 °C till 800 °C with a ramp rate of 10 °C with a helium as carrier gas and a flow rate of 25 ml min ¹. The amount of CO2 desorbed from the sample was detected by the TCD detector. The TCD response was calibrated after every analysis and the amount of CO2 chemisorbed on the sample was calculated.

[0081] Transmission/Scanning Electron Microscopy (T/SEM): To understand morphology of the sample high-resolution transmission electron microscopy (HRTEM) was performed. Sample preparation was done by drop casting small amount of sonicated powder (composition) in ethanol on a carbon coated copper grid. SEM images were taken by FEI NOVA NANOSEM 600 scanning electron microscopes equipped with an energy- dispersive X-ray spectroscopy (ED AX) instrument (Bruker 129 eV ED AX instrument). The data were acquired by using an accelerating voltage of 20 kV and typical time taken for data accumulation is 100 s. The elemental analysis was performed using the P/B-ZAF standard less method (where, P/B = peak to background model, Z = atomic number correction factor, A = absorption correction factor, and F = fluorescence factor) for Fe, Al, K, In, C and O at multiple areas on the sample coated Si wafer.

[0082] Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS): The operando DRIFTS experimental were carried out using a Bruker Vertex 70v FTIR Spectrometer equipped with a Harrick DRIFTS cell. The spectra were recorded at 4 cm' ¹ resolution and each spectrum was averaged 64 times. Each sample (composition) was pre-treated at 400 °C using 99.99% hydrogen (H2) and N2 gas with a total flow rate of 16 ml min ¹ for 30min to obtain the activated catalyst and to remove the adsorbed water and other gas molecules. Then the temperature of the sample was reduced to 30 °C and gas was switched to H2 and CO2 with 1:3 ratio and a flow rate of H2 of 16.66 mimin’¹ and CO₂ of 5.55 ml min’¹. After that, the temperature of the sample was raised slowly from 30 °C to 50 °C with readings taken at an increment of 50 °C in temperature till 300 °C. Finally at 300 °C reaction was carried out for 1 hour and data was taken with an interval of 3 min.

Example 1

Preparation of the composition [0083] The composition of the present disclosure is prepared by wetness impregnation (WI) method as described herein. Stoichiometric amount of potassium nitrate was dissolved in 10 mL of DI (deionized) water, followed by addition of alumina under stirring for 2 min to obtain a uniform mixture. The uniform mixture was dried at 150 °C for 12 h and was ground well to obtain K- promoted alumina. Stoichiometric amount of iron nitrate and indium nitrate were dissolved in 8 mL of DI water to obtain a first solution. K- promoted alumina was added to the first solution under stirring for 5 minutes to obtain a mixture. The mixture was dried at 150 °C for 12 h, was grounded well and was calcined in static air at 400 °C for 4 h with 5 °C/min ramp to obtain the composition. The composition was prepared by varying the weight % of iron nitrate, indium nitrate and by varying K-promoted alumina. In an example, for 2 wt% of indium in the composition, 14 g (0.18 mmol) of iron nitrate and 111 mg (0.18 mmol) of indium nitrate were taken. Indium percentage was varied such as 2, 5, 10, 20 wt%, with respect to total weight of indium and iron being 60%. The preparation process was repeated to obtain various catalyst composition and the composition is represented as In_x_Fe/K-AhO3, x being 2 to 10. In_x_Fe/K-AhO3 is also referred to as In_x_Fe2O3(60-x)/K-AhO3. In_x_Fe/K(y)-AhO3 refers to y% of K, y being 1 to 5% and total of K and AI2O3 was maintained as 40%. Also for comparative purpose the catalyst composition was prepared using only alumina instead of K-promoted alumina.

Example 2

Hydrogenation of carbon dioxide

[0084] Hydrogenation of carbon dioxide using the composition of the present disclosure was carried out using fixed bed vapor phase down flow reactor. Fixed bed vapor phase down flow reactor having a bed volume of 18 cm³ and length of 12 cm with a four- zone heating furnace was used. 4 g of the catalyst composition as prepared in Example 1 was mixed with 16 g of inert alumina as diluent (1:4). The catalyst composition was reduced at 400 °C for 4 h with a flow rate of 20 mL min ¹ of N2 and 80 mL min-1 of H2 to obtain the activated catalyst. The activated catalyst was made in contact with the feed gas of H2/CO2 with volume ratio of 75/25, in which N2 of 4% used as the internal standard. The weight hourly space velocity (WHSV) of the feed gas was maintained at 4000 mLgcat^-1 h^-1 and the hydrogenation was carried out at 300 °C, 20 bar to obtain hydrogenated gas. The hydrogenated gas was condensed at 5 °C to obtain liquid products of higher alcohols. The liquid products also comprised hydrocarbons, lower alcohols, carbon monoxide, or combinations thereof.

Example 3

Analysis of hydrogenated products

[0085] During the reaction, the obtained gases were analyzed in real time by Agilent GC 7890B with TCD and FID as the detector. Hayesep Q and molsieve columns were used to separate CO2, N2 and H2 which was further detected by TCD. The hydrocarbons were separated by using Gaspro column and detected by FID detector. The liquid products were analyzed by GC-MS after 20 hours of reaction. HP-5 column was used to separate all the liquid products and were then detected by MS Quadrapole detector. Detector temperature was kept at 250 °C and the mass range was set to 30 to 300 m/z. The oven was programmed to heat from 40 to 60 °C with 1.5 °C min ¹, later the temperature was raised from 60 °C to 250 °C with a ramp rate of 30 °C min ¹.

Total flow

WHSV = -

Weight of catalyst (g)

Total flow is the combination of flow of CO2 and hydrogen in which CO2in is the number of moles CO2 in the inlet and CO2Out for outlet, similarly N2in and N2out are the inlet and outlet moles of N2, and CO out is the number of moles of CO formed during the reaction

C0₂ Conversion

Ci is the number of moles of Ci hydrocarbons, where i is the number of carbons in the product. [0086] Structural analysis of the catalyst composition of Example 1 was carried out using PXRD and the phases formed were compared with the simulated data from Pearson Crystallographic database. Fe2O3/A12O3 was found to be crystallized in the rhombohedral phase with R3c space group. The major peaks were observed at 20 = 33.2° and 35.6° corresponds to the 104 and 110 crystallographic planes. Upon the introduction of In (indium), the peak at 33.2° shifted slightly to the right which saturated at 2 wt% of In substitution without any further changes up to 10 wt% (Figure 1) and a further increase (20 wt%) resulted in the crystallization of IroOs. This was because the solubility of In at the crystal lattice of Fe in Fe2O3 was around 2-5%. The crystallization of indium at a lower percentage (10 wt%) of composition comprising K-promoted alumina indicated that the solubility limit of In at Fe had been shifted to lower value (~2 wt%) compared to the samples without K-promoted alumina (Figures la, lb). The absence of any K-based oxides or carbonates even for a different K promotion suggested that K was well dispersed on the catalyst. SEM images (Figures 2-5) indicated a uniform distribution of the catalyst composition for In 10_Fe/K-AhO3 and In 20_Fe/K-AhO3 respectively.

[0087] All the catalyst compositions were tested for CO2 reduction using H2 as the reductant in a vapor phase plug flow reactor. The results of the catalytic tests are summarized in Table 1 and the data are plotted in Figure 6. Fe2O3/AhO3 showed a moderate CO2 conversion (22.6%) with CH4 (33.9%), CO (20.0%) and C2- C4°(hydrocarbons-alkanes) (23.8%) as the major products, and negligible amount of HAs and olefins (Figures 6a, 6b). The composition comprising 2% In enhanced the CO2 conversion to 33% with a reduced formation of CH4 (30.3%), CO (8%) and C2-C4⁰ (20%), and an enhanced product distribution towards methanol (9.02%) and HAs (20.09%) (ranging from C2 to Cs). Further increase of In (5%) led to a slightly reduced CO2 conversion (31%) with increased methane (43.42%) and C2-C4⁰ (24.36%) selectivity. Upon further increase in In percentage (10 and 20 wt%), conversion dropped significantly to 18.57% and 13.29% respectively with a concomitant increase in CO selectivity to 40.4% and 50.0% (Figures 6a, 6b). In a similar line, methanol selectivity also has been increased upon In introduction from 5 to 20 wt% with a maximum selectivity of 28.7% was obtained in the case of 20 wt% In, which could be attributed due to progressive enhancement in the I112O3 formation during the synthesis. In another comparison, the formation of Cl products (CO, CH4 and MeOH) has been increased to a maximum of 84% upon increasing In concentration (Figures 6c ,6d).

[0088] The K-promoted alumina catalyst composition of the present disclosure were tested for CO2 reduction at similar conditions. The promotion of the catalysts with K were shown to improve the CO2 conversion and higher hydrocarbons selectivity. Oxides of K being basic increased the electron density on the surface of the catalyst also increased the amount of adsorbed CO2 on the catalyst surface as shown by CO2 TPD studies (Figures 7c, 7d). K promoted catalysts enhanced CO2 reduction compared to unpromoted samples with significant enhancement in the HA selectivity. Maximum conversion of 36.7% had been achieved over the In (2%) catalyst with 42.0% of HA selectivity and C2-C4⁼ ((hydrocarbons-alkenes) selectivity of 8.9% with a very low CO selectivity (7.4%) (Table 1).

Table 1

[0089] In the catalyst composition, the concentration of K on In_2_Fe/K-AhO3 sample was varied from 1-5 wt%. The CO2 conversion was found to be increased by 3-4% compared to the unpromoted sample. However, the major difference was observed in the product distribution. An improvement (20% to 43% selectivity) in the HAs production with optimum amount of K promotion (Figure 6e, 6f) was observed. To account conversion and selectivity at a given time, the yield of different samples towards HA had been calculated. A record yield of HA (15.42%) was obtained for In_2_Fe/K-AhO3 suggesting an optimum K-promotional effects of the catalyst composition.

Conversion of carbon dioxide to Higher alcohols by strain induced phase

[0090] As observed in the PXRD, In had been substituted when it was loaded less than 5%. Upon increasing the amount of In, it crystallized as I Ch as seen in Figures la, lb. Since the size of In ionic size (80 pm) was higher than that of Fe (60 pm), an expansion of the lattice parameters was anticipated, however, the shift towards the higher angle suggested a shift in the XRD peaks towards the lower 20 values. Since the expansion of lattice parameters induced the strain, and the induced strain was calculated from the XRD patterns using Williamson-Hall method. The amount of strain calculated was related to the HA yield %, as both 2 and 5% samples had the highest strain (Table 2) favored high production of HA.

Table 2

[0091] The 10% In loaded catalyst also had similar strain, but favored less HA and more MeOH. This could be attributed to the formation of I112O3, a well-known methanol catalyst, as observed in post reaction PXRD (Figures 9-11). As explained above, the CO2 conversion increased upon K promotion, due to the creation of strong basic sites thereby increasing the amount of CO2 adsorbed, however, the selective enhancement in HA production upon K loading was further analysed. To understand this, the strain of all K promoted catalysts were calculated. A significant enhancement in the strain on In_2_Fe/K-AhO3 compared to other samples (Figure 8) showed, 3.5% K promotion on In_2_Fe/AhO3 produced highest strain, which clearly manifested that the strain induced catalysts favored the best activity towards CO2 to HA conversion.

[0092] To understand the effect of In substitution on the reducibility of the samples, Temperature Programmed Reduction (TPR) was performed from 50 °C to 800 °C. The transformation of FC2O3 to FC3O4 was expected with a reduction peak in the range of 350- 400 °C. The reduction peak in case of as-synthesized Fe2O3/AhO3 observed at 377 °C was not altered even after In substitution confirmed that FC2O3 to FC3O4 remained the same (Figure 7a). On the other hand, the FC3O4 to Fe reduction peak was observed at 546 °C for the as-synthesized Fe2O3/AhO3 sample had been shifted to higher temperature upon In substitution. At higher concentration of In, the decrease in reduction maxima suggested that IroOs suppressed the reducibility of FC3O4 to Fe. A small peak near 800 °C could be attributed to the reduction of I112O3 to In. The promotion of the catalysts with K showed a new peak corresponding to the reduction of K2O to K (Figure 7b). In comparison to unpromoted samples the reduction temperature was high after promotion as K increased the electron density on the surface, which further reduced amount of H2 adsorbed.

[0093] CO2 TPD profiles have been performed on all the samples to understand the interaction of CO2 with the catalyst and how it alters with the introduction of In. CO2 TPD profile showed a single peak confirmed the presence of only one kind of basic site (Figure 7c). The intensity of this peak was observed as similar in the case of both 2% and 5% In substituted samples but broadened upon further increase in In percentage to 10% and 20%. The amount of CO2 adsorbed was slightly increased (11.73 pmolg^-1) upon 2% In substitution (Table 3). The activation energy of this desorption was found to be in the range of 122 kJmoT¹. But the strength was increased upon increase in In percentage from 0 to 20%. On bare Fe the peak maxima was found at 119 °C but this temperature was increased to 129 °C for 20% sample.

[0094] In case of K promoted samples there were two kinds of peaks observed at 122 °C and 547 °C corresponding to weak and strong basic sites, respectively (Figure 7d). The substitution of In influenced the strength of the strong basic sites with a drop in reduction temperature from 547 °C to 523 °C, which affected the amount of CO2 adsorbed (Table 3). The maximum adsorption of CO2 was observed in highly strained catalyst In_2_Fe/K(2)-AhO3 (323.97 pmolg ¹) compared to non-promoted (151 pmolg ¹) and maximum loaded catalyst, In_20_Fe/K(2)-A12O3 (87.64 pmolg ¹).

Table 3

[0095] In-situ Mechanistic Study: To understand the mechanism and intermediates formed during the CO2 reduction reaction, In-situ DRIFTS was also performed (Figure 12). The bare sample without substitution of In (Fc/K-AFOs) favored the formation of CO (adsorbed CO observed at 2137 cm ¹) even at lower temperature (50 °C), however the peaks corresponding to hydrocarbons (2938 cm ¹ and 2875 cm ¹) started to appear at 200 °C. This comprehensively confirmed that the RWGS process was the initial step and the intermediate CO molecules coupled for the formation of HCs (hydrocarbons) and/or HA. The free CO peak was observed at 300 °C (2205 cm ¹) and was continuously seen even after a further increase in temperature. Upon increasing the temperature, the intermediates bidentate formate (1602 cm ¹ and 1359 cm ¹) exhibited negative intensity, whereas carbonates (1560 cm ¹) and mono dentate formate (1655 cm ¹ and 1319 cm ¹) intensity increased progressively (Figures 12a). This showed that the mono dentate formate and carbonates were the major intermediates at 300 °C but the activation at lower temperature took place by bidentate formate formation. Negligible amount of methane (3041 cm ¹) was observed throughout the temperature range. With the introduction of In similar to Fc/K-AhOs it showed the formation of CO, CH4 and CH2 intermediate. Contrasting to Fe it showed the consumption of both bi-dentate (1587 cm ¹) and monodentate formates (1630 cm ¹ and 1304 cm ¹) with the increase in temperature (Figure 12b). Similar to Fe it showed carbonates (1565 cm ¹) are major stable intermediates at 300 °C. But the major difference was the presence of OCH3 intermediate (1058 cm ¹), OCH3 also gave rise to CH4 by dissociative hydrogenation of OCH3. However the CH4 intensity did not change during the process which led to the methanol formation in the case of non-dissociative hydrogenation of OCH3, but in reaction product distribution methanol was less confirming, as it was undergoing coupling with other intermediates and gave rise to HA. But at higher temperatures this peak intensity decreased showing its rapid conversion to other products. Similar to In_2_Fe/K-AhO3, In-5_Fe/K-AhO3 showed similar peaks and intensities (Figures 12c) of the intermediates and showed nearly similar HA and CO selectivity in their product distribution. When this percentage was further increased (In_20_Fe/K-AhO3), carbonates and bidentate formate were the major intermediates, but their corresponding intensities were less which showed its lower ability to activate CO2. OCH3 peak at 1071 cm ¹ was consumed at a lower temperature itself which confirmed that it was undergoing non-dissociative hydrogenation leading to the formation of MeOH (Figures 12d).

Advantages of the present disclosure

[0096] The above-mentioned implementation examples as described on this subject matter and its equivalent thereof have many advantages, including those which are described.

[0097] The present disclosure provides a catalyst composition comprising 1 to 20% (w/w) In; 40 to 60% (w/w) of Fe2O3; 1 to 5% (w/w) of K; and 35 to 40% (w/w) AI2O3. The catalyst composition of the present disclosure in particular catalyses the hydrogenation of carbon dioxide to higher alcohols. The K-promoted alumina catalyst is better performing than unpromoted catalyst composition. The strain induced iron oxide phase of the catalyst composition of the present disclosure promotes the conversion of carbon dioxide to higher alcohols. The present disclosure provides a catalyst and a process hydrogenation of carbon dioxide to a higher alcohol with a selectivity range of 35 to 50% and conversion % of carbon dioxide in a range of 30 to 40%. Also, the process of the present disclosure provides higher alcohol in a yield range of 10 to 25%. The process of the present disclosure also results in other products selected from hydrocarbons such as alkanes, alkenes, methanol, carbon monoxide, or combinations thereof. The present disclosure provides an easily scalable process for conversion of carbon dioxide as it involves low pressure and temperature. Further, the use of low cost catalyst also makes the process economically viable process to be effortlessly adapted on an industrial scale.

Claims

I/We Claim:

1. A composition comprising: a. 1 to 20% (w/w) indium; b. 40 to 60% (w/w) of iron oxide; c. 1 to 5% (w/w) of potassium; and d. 35 to 40% (w/w) alumina.

2. The composition as claimed in claim 1, wherein the composition is a hydrogenation catalyst.

3. The composition as claimed in claimed in claim 1, wherein the composition has a strain induced phase of iron oxide and the strain in the composition is in a range of 0.002 to 0.004.

4. A process for preparing the composition as claimed in claim 1, the process comprising: a. mixing a salt of potassium with alumina to obtain K-promoted alumina; b. contacting an iron salt and an indium salt in presence of a solvent to obtain a first solution; c. adding the K-promoted alumina to the first solution to obtain a mixture; and d. calcining the mixture to obtain the composition.

5. The process as claimed in claim 4, wherein the salt of potassium is an aqueous solution of a salt selected from potassium nitrate, potassium chloride, or combinations thereof.

6. The process as claimed in claim 4, wherein mixing a salt of potassium with alumina is carried out under stirring followed by drying at a temperature in a range of 100 to 160°C.

7. The process as claimed in claim 4, wherein the solvent is water.

8. The process as claimed in claim 4, wherein the iron salt is selected from iron nitrate, iron chloride, or combinations thereof; and the indium salt is selected from indium nitrate, indium chloride, or combinations thereof.

9. The process as claimed in claim 4, wherein adding the K-promoted alumina to the first solution is carried out under stirring followed by heating at a temperature in a range of 100 to 160°C.

10. The process as claimed in claim 4, wherein calcining is carried out at a temperature in a range of 350 to 450°C.

11. A process for hydrogenation of carbon dioxide , the process comprising: a. reducing the composition as claimed in claim 1 at a temperature in a range of 350 to 450°C to obtain an activated catalyst; b. contacting the activated catalyst with a feed gas at a temperature in a range of 250 to 350°C to obtain a hydrogenated gas; and c. condensing the hydrogenated gas to obtain a higher alcohol; wherein the feed gas is a combination of hydrogen and carbon dioxide with a volume ratio in a range of 5:1 to 1:5; and the higher alcohol is selected from C2 to Cs alkanol, or combinations thereof.

12. The process as claimed in claim 11, wherein the composition is diluted with a support in ratio of 1:1 to 1:6.

13. The process as claimed in claim 12, wherein the support is alumina.

14. The process as claimed in claim 11, wherein reducing the composition is carried out in presence of hydrogen gas and optionally nitrogen gas.

15. The process as claimed in claim 14, wherein the hydrogen (H2) gas and the nitrogen gas (N2) are taken in a flow rate of 50 to 100 mL min ¹ of H2 and 10 to 30 mL min ¹ of N2.

16. The process as claimed in claim 11, wherein contacting the activated catalyst with the feed gas is carried out at a weight hourly space velocity (WHS V) in a range of 3000 to 5000 mLgcat^-1 h^-1.

17. The process as claimed in claim 11, wherein hydrogenation of carbon dioxide to a higher alcohol is in a selectivity range of 35 to 50% and conversion % of carbon dioxide is in a range of 30 to 40%.

18. The process as claimed in claim 11, wherein the process further yields hydrocarbons, lower alcohol, carbon monoxide, or combinations thereof.

19. Use of the composition as claimed in claim 1 for hydrogenation of carbondioxide.

20. The use as claimed in claim 19, wherein the composition catalyses hydrogenation of carbondioxide to a higher alcohol selected from one or more of C2 to Cs alkanol.

21. The use as claimed in claim 19, wherein the composition further catalyses the conversion of carbondioxide to a product selected from hydrocarbons, lower alcohol, carbon monoxide, or combinations thereof.