WO2016173285A1 - 一种具有核-壳结构的负载型催化剂及其制备方法与应用 - Google Patents

一种具有核-壳结构的负载型催化剂及其制备方法与应用 Download PDF

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WO2016173285A1
WO2016173285A1 PCT/CN2015/098906 CN2015098906W WO2016173285A1 WO 2016173285 A1 WO2016173285 A1 WO 2016173285A1 CN 2015098906 W CN2015098906 W CN 2015098906W WO 2016173285 A1 WO2016173285 A1 WO 2016173285A1
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noble metal
core
catalyst
supported
shell structure
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French (fr)
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王平
戴洪斌
钟玉洁
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华南理工大学
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/745—Iron
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/75—Cobalt
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/755—Nickel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/04—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by decomposition of inorganic compounds, e.g. ammonia
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Definitions

  • the invention belongs to the technical field of catalytic materials, and particularly relates to a supported catalyst having a core-shell structure and a preparation method and application thereof.
  • Catalytic decomposition of hydrazine hydrate (N 2 H 4 ⁇ H 2 O) to hydrogen is a new integrated hydrogen storage/hydrogen production technology for automotive/mobile hydrogen source applications compared to traditional chemical hydrogen storage (eg, hydroboration).
  • the advantages of sodium, ammonia borane and formic acid technology are: high effective hydrogen storage capacity (8 wt%), no solid by-products, low hydrogen production cost, and safe and convenient material storage and transportation.
  • the effective hydrogen storage component of hydrazine hydrate is hydrazine (N 2 H 4 ), and its decomposition can be carried out in two competitive paths: N 2 H 4 ⁇ N 2 + 2H 2 , 3N 2 H 4 ⁇ 4NH 3 + N 2 . From the viewpoint of hydrogen storage application, it is necessary to selectively promote the decomposition of N 2 H 4 into N 2 and H 2 while effectively suppressing the reaction of decomposing into N 2 and NH 3 .
  • the hydrazine hydrate hydrogen production system is mainly composed of a fuel liquid and a catalyst, and the fuel liquid is an aqueous alkaline solution containing water.
  • the development of a catalyst with high catalytic activity, high hydrogen production selectivity and good durability is the core issue in the development of hydrazine hydrazine decomposition hydrogen production technology. It is found that most of the Group VIII transition metals can catalyze the decomposition of hydrazine hydrate, but the catalytic activity and hydrogen production selectivity are lower at mild temperatures. In response to this problem, two modification methods of catalyst alloying and introduction of carriers are generally employed.
  • the former mainly adjusts the surface electronic structure and geometry of the catalyst to enhance the intrinsic catalytic activity and reaction selectivity; the latter enhances the durability of the catalyst by stabilizing the nanoparticle structure of the catalyst and the strong interaction between the support and the catalyst. active.
  • the supported alloy catalyst has the most promising prospects.
  • the alloy catalyst is mainly composed of non-precious metals and noble metals, non-precious metals including Fe, Co, Ni, precious metals including Ru, Rh, Pd, Ir, Pt. At present, alloy catalysts with better catalytic activity usually have higher precious metal content, which leads to high preparation cost of the catalyst, and limits the practical application of catalytic decomposition of hydrated hydrazine to hydrogen production.
  • Another object of the present invention is to provide a method for producing the above-described supported catalyst having a core-shell structure.
  • Still another object of the present invention is to provide an application of the above-described supported catalyst having a core-shell structure for catalytic decomposition of hydrogen into hydrazine hydrate.
  • a supported catalyst having a core-shell structure wherein the catalyst is a metal oxide as a carrier, a non-noble metal as a core, and an alloy of a non-noble metal and a noble metal as a shell.
  • the metal oxide is preferably a metal oxide having a mesoporous structure, more preferably magnesium oxide (MgO), lanthanum oxide (La 2 O 3 ), cerium oxide (CeO 2 ) or cerium oxide (Eu 2 ) having a mesoporous structure. O 3 ).
  • MgO magnesium oxide
  • La 2 O 3 lanthanum oxide
  • CeO 2 cerium oxide
  • Eu 2 cerium oxide
  • the non-noble metal is preferably iron (Fe), cobalt (Co) or nickel (Ni); the noble metal is preferably ruthenium (Ru), rhodium (Rh), palladium (Pd), iridium (Ir) or platinum (Pt).
  • the preparation method of the above-mentioned supported catalyst having a core-shell structure comprises the following preparation steps:
  • the precipitating agent is added dropwise to the alcohol solution containing the non-noble metal soluble salt and the carrier metal soluble salt at 30-60 ° C under stirring, and the reaction is carried out for 1 to 2 hours, and then reacted at 80 to 100 ° C under sealed conditions for 8 to 12 hours.
  • the precipitate is separated by centrifugation, and the precipitate is dried at 30 to 60 ° C for 8 to 12 hours, then sintered in an air atmosphere at 400 to 600 ° C for 1 to 4 hours, and finally reduced to 1.5 to 3 hours under flowing H 2 atmosphere and 300 to 600 ° C. , that is, a supported non-precious metal precursor;
  • the supported non-precious metal precursor of the step (1) is placed in a homogeneous solution of the noble metal at room temperature and under stirring to carry out the first displacement reaction, the precipitate is separated by centrifugation, and the precipitate is washed and dried for the first sintering. Then, a second displacement reaction is carried out in a homogeneous solution of a noble metal, and after washing and drying, a second sintering is carried out to obtain a supported catalyst having a core-shell structure.
  • the precipitating agent described in the step (1) is preferably an ethanol or methanol solution of tetramethylammonium hydroxide (TMAH); the alcohol solution is preferably an ethanol solution or a methanol solution.
  • TMAH tetramethylammonium hydroxide
  • the non-noble metal soluble salt described in the step (1) is preferably Ni(NO 3 ) 2 , Fe(NO 3 ) 3 or Co(NO 3 ) 2 ;
  • the carrier metal soluble salt is preferably La(NO 3 ) 3 , Ce (NH 4 ) 2 (NO 3 ) 6 , Eu(NO 3 ) 3 or Mg(NO 3 ) 2 ;
  • the molar ratio of the non-noble metal soluble salt to the carrier metal soluble salt is preferably 1:2.
  • the homogeneous solution of the noble metal described in the step (2) is preferably an aqueous solution of H 2 PtCl 6 , an aqueous solution of K 2 PtCl 6 , an aqueous solution of RhCl 3 , an aqueous solution of K 2 PdCl 4 or an aqueous solution of H 2 IrCl 6 .
  • the molar ratio of the precious metal element contained in the homogeneous solution of the noble metal to the non-noble metal element contained in the supported non-precious metal precursor in the first displacement reaction described in the step (2) is 1: (10 to 80); The molar ratio is 1:18; the molar ratio of the precious metal element contained in the homogeneous solution of the noble metal to the non-noble metal element contained in the supported non-precious metal precursor in the second displacement reaction is 1: (5 ⁇ ) 8); The preferred molar ratio is 1:8.
  • the first sintering and the second sintering described in the step (2) mean sintering in a flowing H 2 atmosphere and a temperature of 200 to 600 ° C for 2 to 4 hours; preferably in a flowing H 2 atmosphere and 350 to 400 ° C. Sintered for 2 h under temperature conditions.
  • the non-noble metal soluble salt and the carrier metal soluble salt are coprecipitated by the action of a precipitating agent, and the precipitate is sintered to become a non-precious metal oxide and a carrier metal oxide, and then the non-precious metal oxide is reduced to a metal element by H 2 to obtain a supported type.
  • Precious metal precursor the supported non-precious metal precursor is placed in a homogeneous solution of a noble metal for displacement reaction to obtain a core-shell structure support body with a non-precious metal as a core and a noble metal as a shell, and then sintered under a H 2 atmosphere, a non-precious metal
  • the alloy is interdiffused with the noble metal to form an alloy on the surface of the non-noble metal core, and a supported catalyst having a non-precious metal as a core, an alloy of a non-precious metal and a noble metal as a shell, and a metal oxide as a carrier is obtained.
  • the present invention can produce a supported catalyst having a non-noble metal as a core, an alloy of a non-precious metal and a noble metal as a shell, and a metal oxide as a carrier, since the shell is an alloy of a thin layer of a non-precious metal and a noble metal, Reduce the use of precious metals and reduce the production cost of catalysts;
  • the preparation method of the invention adopts a suitable precipitating agent and a solvent system, so that the formed metal oxide carrier has a good mesoporous structure, can increase the contact of the reactant with the catalyst, and at the same time, due to the confinement effect of the mesoporous structure, It can prevent the agglomeration of the supported catalyst nanoparticles, so that the catalytic performance of the catalyst is fully exerted;
  • the catalyst of the present invention has high catalytic activity, high hydrogen production selectivity, and good durability.
  • Example 1 is an N 2 adsorption/desorption isotherm diagram of Ni/La 2 O 3 , Ni@Ni—Pt/La 2 O 3 obtained in Example 1 and Pt/La 2 O 3 catalyst obtained in Comparative Example 1;
  • FIG. 3 is a graph showing the different Pt contents of Ni@Ni-Pt/La 2 O 3 , Ni/La 2 O 3 and the Pt/La 2 O 3 catalyst obtained in Comparative Example 1 in the hydrogen production of hydrazine hydrate decomposition. Comparison of reaction rate and hydrogen production selectivity;
  • Figure 5 is a graph showing the results of durability test of the supported catalyst Fe@Fe-Rh/CeO 2 of Example 3;
  • Fig. 7 is a graph showing the results of durability test of the supported catalyst Ni@Ni-Ir/MgO of Example 5.
  • Fuel liquid 4mL 0.5M N 2 H 4 ⁇ H 2 O+1.0M NaOH;
  • Catalyst Catalyst obtained in each of the examples and comparative examples.
  • the hydrogen production performance test (catalytic performance test of the catalyst) uses the following method:
  • the volume of the generated gas (N 2 + H 2 ) was measured by the drainage method, and the amount of the mixed gas substance was calculated using the ideal gas state equation.
  • the specific operation is as follows: the gas generated by the reaction is pickled (used to absorb the NH 3 which may be generated by the decomposition of hydrazine), and is introduced into the water-washed Meng's bottle. The quality of the discharged water is automatically recorded by the balance with an accuracy of 0.01 g.
  • the relationship of time It is assumed that the time required for the decomposition of hydrazine hydrate to 50% is used to calculate the reaction rate or switching frequency (TOF, h –1 ), and the hydrogen production selectivity (X) is calculated by the following formula:
  • a supported catalyst of the present invention having a core-shell structure, Ni@Ni-Pt/La 2 O 3 , is prepared as follows:
  • step (1) 5 parts of the supported non-precious metal precursor Ni/La 2 O 3 of step (1) were placed in 20 mL of different concentrations of H 2 PtCl 6 aqueous solution at room temperature and magnetic stirring (adjusting different concentrations of H 2 PtCl 6 aqueous solution)
  • the first substitution reaction was carried out by making the molar ratio of Pt element to Ni element in the catalyst 1/78, 1/58, 1/38, 1/18 and 1/8, respectively, and the reaction was carried out for 1 hour, and the precipitate was separated by centrifugation, and the precipitation was carried out in sequence.
  • a supported catalyst Ni@Ni-Pt/La 2 O 3 having a core-shell structure
  • the N 2 adsorption/desorption isotherms of the Pt/La 2 O 3 catalyst obtained in Example 1 obtained from Ni/La 2 O 3 , Ni@Ni–Pt/La 2 O 3 and Comparative Example 1 are shown in FIG. 1 . It can be seen from Fig. 1 that all three materials show a type IV isotherm, and the adsorption line and the desorption line are not heavier, and have a hysteresis loop, indicating that all three substances have a mesoporous structure.
  • the adsorption/desorption isotherms can be obtained by the Brunauer-Emmett-Teller (BET) method and the Barrett-Joyner-Halenda (BJH) model: Ni/La 2 O 3 , Ni@Ni–Pt/La 2 O 3 and Pt/
  • BET Brunauer-Emmett-Teller
  • BJH Barrett-Joyner-Halenda
  • the specific surface areas of La 2 O 3 were 34.4, 73.2, and 55.4 m 2 /g, respectively, and the average pore diameters were 10.8, 6.5, and 7.6 nm, respectively.
  • Ni/La 2 O 3 and Ni@Ni-Pt/La 2 O 3 catalysts were prepared as in Example 1, except that the TMAH ethanol solution in step (1) was replaced with an aqueous solution of the same concentration of NaOH; The (NO 3 ) 2 and La(NO 3 ) 3 ethanol solutions were changed to an aqueous solution of the same substance concentration, and the rest were identical, and Ni/La 2 O 3 and Ni@Ni–Pt/La 2 O 3 of the present comparative examples were obtained. catalyst.
  • the N 2 adsorption/desorption isotherms of the Ni/La 2 O 3 and Ni@Ni–Pt/La 2 O 3 catalysts obtained in the present comparative examples are shown in Fig. 2 . It can be seen from Fig. 2 that both substances show type II isotherms, indicating that neither substance has a mesoporous structure. This is because the supported non-precious metal precursor prepared according to the method of the step (1) of Example 1 uses ethanol or methanol as a solvent and the organic base TMAH as a precipitant, and the organic solvent adsorbed during the sintering process and the residual relatively long chain.
  • the removal of the organic base TMAH forms the mesoporous structure of the metal oxide support, and after replacing the organic base TMAH with NaOH and replacing the solvent from the alcohol solution to water, the resulting metal oxide support will have no mesoporous structure.
  • Example 1 Ni@Ni-Pt/La 2 O 3 without a second displacement reaction
  • Ni/La 2 O 3 Ni/La 2 O 3
  • the Pt/La 2 O 3 catalyst has no activity on hydrazine hydrate, while Ni/La 2 O 3 exhibits lower activity and hydrogen production selectivity.
  • the activity and selectivity of the catalyst are greatly improved, for example, when the Pt/Ni molar ratio is 1 compared to Ni/La 2 O 3 . /78, the catalytic activity of the obtained Ni@Ni-Pt/La 2 O 3 is increased by 3 times, the hydrogen production selectivity is increased from 72% to 92%; when the Pt/Ni molar ratio is 1/18, the prepared catalyst is The activity is best. At 50 ° C, hydrazine hydrate decomposes for 7 minutes, and its hydrogen production selectivity increases to 97%. However, the Pt/Ni molar ratio continues to increase and the performance of the catalyst decreases.
  • a supported catalyst of the present invention having a core-shell structure, Ni@Ni-Pt/La 2 O 3 , is prepared as follows:
  • the supported non-precious metal precursor Ni/La 2 O 3 of step (1) was placed in 20 mL of K 2 PtCl 6 aqueous solution at room temperature under magnetic stirring (adjusting the concentration of K 2 PtCl 6 aqueous solution to make Pt element and Ni in the catalyst) The molar ratio of the element is 1:18).
  • the first displacement reaction is carried out, and the reaction is carried out for 1 hour.
  • the precipitate is separated by centrifugation.
  • the precipitate is washed with water, alcohol washed, and subjected to dynamic vacuum drying at 30 ° C for 12 h, then in a flowing H 2 atmosphere.
  • the catalyst of the four batches of the supported catalyst Ni@Ni-Pt/La 2 O 3 having a core-shell structure and the Pt/Ni molar ratio in Example 1 was 1/18, and the second displacement reaction was not carried out.
  • the hydrogenation performance of the catalyst which was not sintered in the second displacement reaction was compared, and the results are shown in Table 1.
  • the hydrogen production selectivity of the catalyst is up to 97% by one displacement reaction, but this means that a certain amount of NH 3 is simultaneously produced, and NH 3 is harmful to the operation of the acid proton exchange membrane fuel cell. Will poison the fuel cell.
  • the present invention prepares Ni@Ni-Pt/La 2 by a secondary displacement reaction, that is, a "secondary alloying" treatment of the "primary alloying” catalyst, followed by sintering in a flowing H 2 atmosphere at 350 ° C for 2 h.
  • the O 3 catalyst has the best performance.
  • the chemical composition has a composition of 48.4 mol% Ni 88.4 Pt 11.6 /51.6 mol% La 2 O 3 , and its hydrogen production selectivity can reach 100%.
  • hydrazine hydrate decomposition takes 2.6 minutes.
  • the reaction rate can reach 312h –1 . If the sintering temperature is too high or too low, it will adversely affect the performance of the catalyst. Inappropriate heat treatment will affect the diffusion of Ni and Pt on the surface of the Ni core, thus affecting the performance of the catalyst.
  • the durability test of the catalyst was carried out (cycled according to the hydrogen production method), and the results are shown in the figure. 4 is shown. It can be seen from Fig. 4 that at 50 ° C, the Ni@Ni-Pt/La 2 O 3 catalyst is used for 10 cycles, and the catalyst can still maintain 82% of its initial activity, but the 100% hydrogen production selectivity is almost unchanged.
  • a supported catalyst Fe@Fe-Rh/CeO 2 having a core-shell structure of the present embodiment is prepared as follows:
  • step (1) At room temperature with magnetic stirring, in step (1) is supported non-noble metal precursor Fe / CeO 2 was placed 20 mL aqueous solution of RhCl 3 (aq adjusting the concentration of RhCl 3 molar ratio of Rh in the catalyst element and Fe element 1 /10) The first displacement reaction was carried out, the reaction was carried out for 1 h, and the precipitate was separated by centrifugation. The precipitate was washed successively with water, alcohol washed, and subjected to dynamic vacuum drying at 30 ° C for 12 h, and then in a tubular furnace at 400 ° C under a flowing H 2 atmosphere.
  • RhCl 3 aq adjusting the concentration of RhCl 3 molar ratio of Rh in the catalyst element and Fe element 1 /10
  • the supported catalyst Fe@Fe-Rh/CeO 2 of this example was subjected to a catalyst durability test (cycled according to a hydrogen production method), and the results are shown in Fig. 5.
  • Fig. 5 As can be seen from Fig. 5, at 50 ° C, Fe The initial activity and hydrogen production selectivity of the @Fe-Rh/CeO 2 catalyst were 508 h -1 and 100%, respectively, and the activity and hydrogen production selectivity were almost unchanged after 20 cycles.
  • a supported catalyst Co@Co-Pd/Eu 2 O 3 having a core-shell structure of the present embodiment is prepared as follows:
  • the supported non-precious metal precursor Co/Eu 2 O 3 of step (1) was placed in 20 mL of K 2 PdCl 4 aqueous solution at room temperature with magnetic stirring (adjusting the concentration of K 2 PdCl 4 aqueous solution to make Pd element and Co in the catalyst) The molar ratio of the element is 1/18).
  • the first displacement reaction is carried out, and the reaction is carried out for 1 hour.
  • the precipitate is separated by centrifugation.
  • the precipitate is washed successively with water, washed with alcohol, and subjected to dynamic vacuum drying at 30 ° C for 12 h, then in a flowing H 2 atmosphere.
  • the supported catalyst Co@Co-Pd/Eu 2 O 3 of this example was subjected to a catalyst durability test (cycled according to a hydrogen production method), and the results are shown in Fig. 6, which can be seen from Fig. 6 at 50 °C.
  • the initial activity and hydrogen production selectivity of Co@Co-Pd/Eu 2 O 3 catalyst were 286 h -1 and 100%, respectively. After 15 cycles, the activity decreased by 13%, but the hydrogen production selectivity was almost unchanged. .
  • a supported catalyst of the present invention having a core-shell structure, Ni@Ni-Ir/MgO, is prepared as follows:
  • a supported non-noble metal precursor Ni step (1) / MgO was placed 20mL H 2 IrCl 6 solution (for adjusting the concentration of H 2 IrCl 6 solution in the catalyst element and a Ni element Ir molar The ratio was 1/18), the first displacement reaction was carried out, the reaction was carried out for 1 hour, and the precipitate was separated by centrifugation. The precipitate was washed with water, alcohol washed, and subjected to dynamic vacuum drying at 30 ° C for 12 h, and then in a tubular furnace under a flowing H 2 atmosphere.
  • the supported catalyst Ni@Ni-Ir/MgO of this example was subjected to a catalyst durability test (cycled by a hydrogen production method), and the results are shown in Fig. 7. It can be seen from Fig. 7 that at 50 ° C, Ni@ The initial activity and hydrogen production selectivity of the Ni–Ir/MgO catalyst were 240 h –1 and 100%, respectively. After 15 cycles, the activity decreased by 20%, but the hydrogen production selectivity was almost unchanged.

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Abstract

本发明属于催化材料技术领域，公开了一种具有核-壳结构的负载型催化剂及其制备方法与应用。所述催化剂的制备方法为：将非贵金属可溶性盐和载体金属可溶性盐的醇溶液在沉淀剂的作用下共沉淀，然后将沉淀进行烧结和还原，得到负载型非贵金属前驱体，然后将负载型非贵金属前驱体与贵金属的均相溶液进行两次置换反应和烧结反应，得到以介孔金属氧化物为载体，以非贵金属为核，以非贵金属和贵金属的合金为壳的负载型催化剂。本发明的催化剂通过形成负载型核-壳结构，壳为薄层非贵金属和贵金属的合金，可显著减少贵金属的用量，降低催化剂的生产成本，在水合肼催化分解制氢过程中具有良好的催化效率及制氢选择性。

Description

一种具有核-壳结构的负载型催化剂及其制备方法与应用 技术领域
本发明属于催化材料技术领域，具体涉及一种具有核-壳结构的负载型催化剂及其制备方法与应用。
背景技术
水合肼(N2H4·H2O)催化分解制氢是一项颇具车载/移动氢源应用前景的储/制氢一体化新技术，其相比于传统化学储氢(例如，硼氢化钠、氨硼烷和甲酸)技术的优势在于：有效储氢容量高(8wt％)、无固体副产物、制氢成本低、材料储运安全简便。水合肼的有效储氢组分为肼(N2H4)，其分解可按两条竞争性路径进行：N2H4→N2+2H2，3N2H4→4NH3+N2。从储氢应用角度，需选择性促进N2H4分解为N2和H2，同时有效抑制其分解为N2和NH3的反应。
水合肼制氢体系主要由燃料液和催化剂组成，燃料液为含水合肼的碱性水溶液。研制兼具高催化活性、高制氢选择性、良好耐久性的催化剂是发展水合肼分解制氢技术的核心课题。研究发现：多数第Ⅷ族过渡金属可催化水合肼分解反应，但在温和温度下的催化活性和制氢选择性均较低。针对此问题，通常采用催化剂合金化和引入载体两种改性方法。前者主要是调变催化剂的表面电子结构和几何构型，以提高本征催化活性和反应选择性；后者则通过稳定催化剂的纳米颗粒结构和载体与催化剂的强相互作用提高催化剂的耐久性及活性。综合考虑催化性能和材料成本，负载型合金催化剂最具发展前景。合金催化剂主要由非贵金属和贵金属组成，非贵金属包括Fe、Co、Ni，贵金属包括Ru、 Rh、Pd、Ir、Pt。目前，催化活性较好的合金催化剂，通常贵金属含量较高，导致催化剂的制备成本高，限制了水合肼催化分解制氢的实际应用。
发明内容
为了解决现有技术的缺点和不足之处，本发明的首要目的在于提供一种具有核-壳结构的负载型催化剂。
本发明的另一目的在于提供上述具有核-壳结构的负载型催化剂的制备方法。
本发明的再一目的在于提供上述具有核-壳结构的负载型催化剂在水合肼催化分解制氢中的应用。
本发明目的通过以下技术方案实现：
一种具有核-壳结构的负载型催化剂，所述催化剂是以金属氧化物为载体，以非贵金属为核，以非贵金属和贵金属的合金为壳。
所述的金属氧化物优选具有介孔结构的金属氧化物，更优选具有介孔结构的氧化镁(MgO)、氧化镧(La2O3)、氧化铈(CeO2)或氧化铕(Eu2O3)。
所述的非贵金属优选铁(Fe)、钴(Co)或镍(Ni)；贵金属优选钌(Ru)、铑(Rh)、钯(Pd)、依(Ir)或铂(Pt)。
上述具有核-壳结构的负载型催化剂的制备方法，包括以下制备步骤：
(1)共沉淀法制备负载型非贵金属前驱体：
将沉淀剂在30～60℃和搅拌下，逐滴加入含非贵金属可溶性盐和载体金属可溶性盐的醇溶液中，反应1～2h，然后在80～100℃和密封条件下反应8～12h，离心分离沉淀，沉淀在30～60℃条件下干燥8～12h，然后在空气气氛和400～600℃条件下烧结1～4h，最后在流动H2气氛和300～600℃条件下还原1.5～3h，即得负载型非贵金属前驱体；
(2)置换法制备具有核-壳结构的负载型催化剂：
在室温及搅拌条件下，将步骤(1)的负载型非贵金属前驱体置于贵金属的均相溶液中进行第一次置换反应，离心分离沉淀，将沉淀进行洗涤干燥后进行第一次烧结，然后置于贵金属的均相溶液中进行第二次置换反应，经洗涤干燥后进行第二次烧结，即得具有核-壳结构的负载型催化剂。
步骤(1)中所述的沉淀剂优选四甲基氢氧化铵(TMAH)的乙醇或甲醇溶液；所述的醇溶液优选乙醇溶液或甲醇溶液。
步骤(1)中所述的非贵金属可溶性盐优选Ni(NO3)2、Fe(NO3)3或Co(NO3)2；所述的载体金属可溶性盐优选La(NO3)3、Ce(NH4)2(NO3)6、Eu(NO3)3或Mg(NO3)2；非贵金属可溶性盐与载体金属可溶性盐的摩尔比优选为1:2。
步骤(2)中所述的贵金属的均相溶液优选H2PtCl6水溶液、K2PtCl6水溶液、RhCl3水溶液、K2PdCl4水溶液或H2IrCl6水溶液。
步骤(2)中所述的第一次置换反应中贵金属的均相溶液所含的贵金属元素与负载型非贵金属前驱体所含的非贵金属元素的摩尔比为1:(10～80)；优选的摩尔比为1:18；所述的第二次置换反应中贵金属的均相溶液所含的贵金属元素与负载型非贵金属前驱体中所含的非贵金属元素的摩尔比为1:(5～8)；优选的摩尔比为1:8。
步骤(2)中所述的第一次烧结和第二次烧结是指在流动的H2气氛和200～600℃温度条件下烧结2～4h；优选在流动的H2气氛和350～400℃温度条件下烧结2h。
上述具有核-壳结构的负载型催化剂在水合肼催化分解制氢中的应用，所述应用包括以下步骤：在所述负载型催化剂的催化作用下，含N2H4·H2O的燃料液分解得到H2。
本发明基于的原理为：
首先非贵金属可溶性盐和载体金属可溶性盐在沉淀剂的作用下共沉淀，沉淀经过烧结成为非贵金属氧化物和载体金属氧化物，然后非贵金属氧化物经过H2还原成为金属单质，得到负载型非贵金属前驱体；将负载型非贵金属前驱体 置于贵金属的均相溶液进行置换反应，得到以非贵金属为核、贵金属为壳的核-壳结构负载体，然后在H2气氛下烧结，非贵金属和贵金属相互扩散在非贵金属核表面形成合金，得到以非贵金属为核、以非贵金属和贵金属的合金为壳、以金属氧化物为载体的负载型催化剂。
本发明的产物及制备方法具有如下优点及有益效果：
(1)本发明通过制备以非贵金属为核、以非贵金属和贵金属的合金为壳、以金属氧化物为载体的负载型催化剂，由于壳为薄层非贵金属和贵金属的合金，因此，可显著减少贵金属的使用量，降低催化剂的生产成本；
(2)本发明的制备方法选用合适的沉淀剂和溶剂体系，使得生成的金属氧化物载体具有良好的介孔结构，能增加反应物与催化剂的接触，同时由于介孔结构的限域作用，能够阻止负载的催化剂纳米颗粒的团聚，使得催化剂的催化性能得到充分发挥；
(3)本发明的催化剂具有高催化活性、高制氢选择性和良好耐久性。
附图说明
图1为实施例1得到的Ni/La2O3、Ni@Ni–Pt/La2O3与对比例1得到的Pt/La2O3催化剂的N2吸附/脱附等温线图；
图2为对比例2得到的Ni/La2O3和Ni@Ni–Pt/La2O3催化剂的N2吸附/脱附等温线图；
图3为实施例1得到的不同Pt含量的Ni@Ni–Pt/La2O3、Ni/La2O3和对比例1得到的Pt/La2O3催化剂在水合肼分解的制氢中的反应速率和制氢选择性对比图；
图4为实施例2的负载型催化剂Ni@Ni–Pt/La2O3的耐久性实验结果图；
图5为实施例3的负载型催化剂Fe@Fe–Rh/CeO2的耐久性实验结果图；
图6为实施例4的负载型催化剂Co@Co–Pd/Eu2O3的耐久性实验结果图；
图7为实施例5的负载型催化剂Ni@Ni–Ir/MgO的耐久性实验结果图。
具体实施方式
下面结合实施例及附图对本发明作进一步详细的描述，但本发明的实施方式不限于此。
以下实施例及对比例得到的催化剂的制氢方法及制氢性能测试如下：
制氢体系的构建：
燃料液：4mL 0.5M N2H4·H2O+1.0M NaOH；
催化剂：各实施例及对比例得到的催化剂。
制氢方法：
将0.2mmol催化剂置于温度为50℃的4mL 0.5M N2H4·H2O+1.0M NaOH燃料液中，即可启动N2H4·H2O催化分解反应，催化剂/N2H4·H2O摩尔比＝1/10。
制氢过程所涉及的反应方程式如下：
N2H4→N2+2H2；
3N2H4→4NH3+N2。
制氢性能测试(催化剂的催化性能测试)采用如下方法：
用排水法测量产生的气体(N2+H2)体积，采用理想气体状态方程计算混合气体物质的量。具体操作为：反应产生的气体，经酸洗(用于吸收肼分解可能产生的NH3)，导入装水的孟氏洗瓶，所排出水的质量，采用精度0.01g的天平自动记录质量和时间的关系。假设水合肼分解50％所需的时间用来计算反应速率或转换频率(TOF，h–1)，而制氢选择性(X)用下列公式计算：
Figure PCTCN2015098906-appb-000001
(Y为产生的气体(N2+H2)与N2H4·H2O的摩尔比)。
实施例1
本实施例的一种具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3，其制备方法如下：
(1)共沉淀法制备负载型非贵金属前驱体Ni/La2O3：
将20mL 2.1M TMAH乙醇溶液，在60℃和磁力搅拌下，逐滴加入60mL0.083M Ni(NO3)2和0.17M La(NO3)3的乙醇溶液中，反应1h，转入衬四氟的反应釜中，在100℃和密封条件下，反应12h，经离心分离得到沉淀，沉淀在60℃温度下干燥12h，然后将沉淀移入管式炉中，在空气气氛和500℃温度下烧结2h，最后在流动H2气氛和500℃温度下还原1.5h，即得负载型非贵金属前驱体Ni/La2O3；
(2)置换法制备具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3：
在室温及磁力搅拌下，将5份步骤(1)的负载型非贵金属前驱体Ni/La2O3分别置于20mL不同浓度的H2PtCl6水溶液中(调节不同浓度的H2PtCl6水溶液使催化剂中Pt元素与Ni元素的摩尔比分别为1/78、1/58、1/38、1/18和1/8)进行第一次置换反应，反应1h，离心分离沉淀，沉淀依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛下于管式炉中在350℃温度下烧结2h，即得经第一次置换反应5批次不同Pt含量的具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3。
本实施例的制备过程中所发生的化学反应如下：
Ni2++2OH–→Ni(OH)2↓
La3++3OH–→La(OH)3↓
Ni(OH)2→NiO+H2O
NiO+H2→Ni+H2O
2La(OH)3→La2O3+3H2O
2Ni+PtCl6 2–→2Ni2++Pt+6Cl–。
对比例1
共沉淀法制备Pt/La2O3催化剂：
将20mL3.0M TMAH乙醇溶液，在60℃和磁力搅拌下，逐滴加入60mL0.083M H2PtCl6和0.17M La(NO3)3的乙醇溶液中，反应1h，转入衬四氟的反应釜中，在100℃和密封条件下，反应12h，经离心分离得到沉淀，沉淀在60℃温度下干燥12h，然后将沉淀移入管式炉中，在空气气氛和500℃温度下烧结2h，最后在流动H2气氛和500℃温度下还原1.5h，即得Pt/La2O3催化剂。
实施例1得到的Ni/La2O3、Ni@Ni–Pt/La2O3与对比例1得到的Pt/La2O3催化剂的N2吸附/脱附等温线如图1所示。由图1可以看出，3种物质均显示了Ⅳ型等温线，并且吸附线和脱附线不重和，具有滞后环，表明3种物质均具有介孔结构。经Brunauer-Emmett-Teller(BET)法和Barrett-Joyner-Halenda(BJH)模型处理吸附/脱附等温线可得到：Ni/La2O3、Ni@Ni–Pt/La2O3和Pt/La2O3的比表面积分别为34.4、73.2和55.4m2/g，平均孔径分别为10.8、6.5和7.6nm。
对比例2
按实施例1的方法制备Ni/La2O3和Ni@Ni–Pt/La2O3催化剂，不同之处在于将步骤(1)中的TMAH乙醇溶液换为同等浓度的NaOH水溶液；将Ni(NO3)2和La(NO3)3的乙醇溶液换为同等物质浓度的水溶液，其余部分完全相同，得到本对比例的Ni/La2O3和Ni@Ni–Pt/La2O3催化剂。
本对比例所得Ni/La2O3和Ni@Ni–Pt/La2O3催化剂的N2吸附/脱附等温线如 图2所示。由图2可以看出，2种物质均显示了Ⅱ型等温线，表明2种物质均不具有介孔结构。这是因为依照实施例1步骤(1)的方法制备的负载型非贵金属前驱体采用乙醇或甲醇为溶剂和有机碱TMAH为沉淀剂，在烧结过程中吸附的有机溶剂和残余的相对具有长链的有机碱TMAH脱去形成了金属氧化物载体的介孔结构，而将有机碱TMAH替换为NaOH和将溶剂由醇溶液换为水后，所得金属氧化物载体将不具有介孔结构。
实施例1的5批次不同Pt含量的具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3(未进行第二次置换反应)、Ni/La2O3(Pt/Ni＝0)和对比例1的Pt/La2O3催化剂在水合肼分解的制氢反应速率和制氢选择性对比如图3所示。从图3可以看出：Pt/La2O3催化剂对水合肼没有活性，而Ni/La2O3展示了较低的活性和制氢选择性。而当Ni和Pt通过第一次置换反应和烧结处理形成Ni–Pt合金，催化剂的活性和选择性大幅度提高，例如，相比于Ni/La2O3，当Pt/Ni摩尔比为1/78，所得Ni@Ni–Pt/La2O3的催化活性增加了3倍，制氢选择性从72％增加到92％；当Pt/Ni摩尔比为1/18时，制备的催化剂的活性最好，在50℃，水合肼分解需7分钟，其制氢选择性增加到97％，然而，继续增加Pt/Ni摩尔比，催化剂的性能下降。
实施例2
本实施例的一种具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3，其制备方法如下：
(1)共沉淀法制备负载型非贵金属前驱体Ni/La2O3：与实施例1相同；
(2)二次置换法制备具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3：
在室温及磁力搅拌下，将步骤(1)的负载型非贵金属前驱体Ni/La2O3置于 20mL K2PtCl6水溶液中(调节K2PtCl6水溶液的浓度使催化剂中Pt元素与Ni元素的摩尔比为1：18)进行第一次置换反应，反应1h，离心分离沉淀，沉淀依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛下于管式炉中在350℃温度下烧结2h，然后将烧结后的产物置于20mL K2PtCl6水溶液中(调节K2PtCl6水溶液的浓度使催化剂中Pt元素与Ni元素的摩尔比为1：8)进行第二次置换反应，产物依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛下，将4份经上述处理后的产物分别于250℃、350℃、450℃和600℃下烧结2h，即得4批次具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3。
本实施例的4批次具有核-壳结构的负载型催化剂Ni@Ni–Pt/La2O3与实施例1中Pt/Ni摩尔比为1/18，未进行第二次置换反应的催化剂和进行第二次置换反应未烧结的催化剂进行制氢性能的对比，结果如表1所示。
表1
Figure PCTCN2015098906-appb-000002
由表1可以看出，通过一次置换反应，催化剂的制氢选择性最高可达97％，但这意味着同时产生了一定量的NH3，NH3对酸性质子交换膜燃料电池的操作有害，会使燃料电池中毒。而本发明通过二次置换反应，即对“一次合金化”的催化剂进行“二次合金化”处理，然后在流动H2气氛和350℃下烧结2h，制备的Ni@Ni–Pt/La2O3催化剂性能最佳，经化学分析其组成为48.4mol％ Ni88.4Pt11.6/51.6mol％La2O3，其制氢选择性可达100％，在50℃，水合肼分解需2.6分钟，反应速率可达312h–1。烧结温度过高或过低，对催化剂的性能均有不利影响，不恰当的热处理会影响Ni和Pt在Ni核表面的扩散，从而影响了催化剂的性能。
取本实施例的负载型催化剂Ni@Ni–Pt/La2O3(第二次置换反应后烧结温度为350℃)进行催化剂的耐久性实验(按制氢方法进行循环使用)，结果如图4所示。由图4可以看出：在50℃，Ni@Ni–Pt/La2O3催化剂经10次循环使用，催化剂仍能保持其初始活性的82％，但100％制氢选择性几乎没变。
实施例3
本实施例的一种具有核-壳结构的负载型催化剂Fe@Fe–Rh/CeO2，其制备方法如下：
(1)共沉淀法制备负载型非贵金属前驱体Fe/CeO2：
将20mL 1.6M TMAH乙醇溶液，在30℃和磁力搅拌下，逐滴加入60mL0.067M Fe(NO3)3和0.067M Ce(NH4)2(NO3)6的乙醇溶液中，反应2h，转入衬四氟的反应釜中，在80℃和密封条件下，反应12h，经离心分离得到沉淀，沉淀在30℃温度下干燥12h，然后将沉淀移入管式炉中，在空气气氛和400℃温度下烧结4h，最后在流动H2气氛和450℃温度下还原3h，即得负载型非贵金属前驱体Fe/CeO2；
(2)置换法制备具有核-壳结构的负载型催化剂Fe@Fe–Rh/CeO2：
在室温及磁力搅拌下，将步骤(1)的负载型非贵金属前驱体Fe/CeO2置于20mL RhCl3水溶液中(调节RhCl3水溶液的浓度使催化剂中Rh元素与Fe元素的摩尔比为1/10)进行第一次置换反应，反应1h，离心分离沉淀，沉淀依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛下于管式炉中在400℃温度下烧结2h，然后将烧结后的产物置于20mL RhCl3水溶液中 (调节RhCl3水溶液的浓度使催化剂中Rh元素与Fe元素的摩尔比为1/5)进行第二次置换反应，产物依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛和400℃下烧结2h，即得具有核-壳结构的负载型催化剂Fe@Fe–Rh/CeO2。经测试所得催化剂具有介孔结构，化学分析其组成为32.4mol％Fe82.8Rh17.2/67.6mol％CeO2。
本实施例的负载型催化剂Fe@Fe–Rh/CeO2进行催化剂的耐久性实验(按制氢方法进行循环使用)，结果如图5所示，由图5可以看出：在50℃，Fe@Fe–Rh/CeO2催化剂的初始活性和制氢选择性分别为508h–1和100％，经20次循环使用，其活性和制氢选择性几乎不变。
实施例4
本实施例的一种具有核-壳结构的负载型催化剂Co@Co–Pd/Eu2O3，其制备方法如下：
(1)共沉淀法制备负载型非贵金属前驱体Co/Eu2O3：
将20mL 2.1M TMAH甲醇溶液，在50℃和磁力搅拌下，逐滴加入60mL0.083M Co(NO3)2和0.17M Eu(NO3)3的甲醇溶液中，反应1h，转入衬四氟的反应釜中，在80℃和密封条件下，反应12h，经离心分离得到沉淀，沉淀在60℃温度下干燥8h，然后将沉淀移入管式炉中，在空气气氛和600℃温度下烧结1h，最后在流动H2气氛和600℃温度下还原1.5h，即得负载型非贵金属前驱体Co/Eu2O3；
(2)置换法制备具有核-壳结构的负载型催化剂Co@Co–Pd/Eu2O3：
在室温及磁力搅拌下，将步骤(1)的负载型非贵金属前驱体Co/Eu2O3置于20mL K2PdCl4水溶液中(调节K2PdCl4水溶液的浓度使催化剂中Pd元素与Co元素的摩尔比为1/18)进行第一次置换反应，反应1h，离心分离沉淀，沉淀依 次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛下于管式炉中在400℃温度下烧结2h，然后将烧结后的产物置于20mL K2PdCl4水溶液中(调节K2PdCl4水溶液的浓度使催化剂中Pd元素与Co元素的摩尔比为1/8)进行第二次置换反应，产物依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛和400℃下烧结2h，即得具有核-壳结构的负载型催化剂Co@Co–Pd/Eu2O3。经测试所得催化剂具有介孔结构，化学分析其组成为47.8％Co87.3Pd12.7/53.2mol％Eu2O3。
本实施例的负载型催化剂Co@Co–Pd/Eu2O3进行催化剂的耐久性实验(按制氢方法进行循环使用)，结果如图6所示，由图6可以看出：在50℃，Co@Co–Pd/Eu2O3催化剂的初始活性和制氢选择性分别为286h–1和100％，经15次循环使用，其活性下降了13％，但制氢选择性几乎不变。
实施例5
本实施例的一种具有核-壳结构的负载型催化剂Ni@Ni–Ir/MgO，其制备方法如下：
(1)共沉淀法制备负载型非贵金属前驱体Ni/MgO：
将20mL 2.1M TMAH乙醇溶液，在50℃和磁力搅拌下，逐滴加入60mL0.083M Ni(NO3)2和0.17M Mg(NO3)2的乙醇溶液中，反应1h，转入衬四氟的反应釜中，在100℃和密封条件下，反应12h，经离心分离得到沉淀，沉淀在50℃温度下干燥12h，然后将沉淀移入管式炉中，在空气气氛和500℃温度下烧结2h，最后在流动H2气氛和300℃温度下还原1.5h，即得负载型非贵金属前驱体Ni/MgO；
(2)置换法制备具有核-壳结构的负载型催化剂Ni@Ni–Ir/MgO：
在室温及磁力搅拌下，将步骤(1)的负载型非贵金属前驱体Ni/MgO置于20mL H2IrCl6水溶液中(调节H2IrCl6水溶液的浓度使催化剂中Ir元素与Ni元素的摩尔比为1/18)进行第一次置换反应，反应1h，离心分离沉淀，沉淀依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛下于管式炉中在350℃温度下烧结2h，然后将烧结后的产物置于20mL H2IrCl6水溶液中(调节H2IrCl6水溶液的浓度使催化剂中Ir元素与Ni元素的摩尔比为1/8)进行第二次置换反应，产物依次进行水洗、醇洗、在30℃温度下动态真空干燥12h，然后在流动H2气氛和350℃下烧结2h，即得具有核-壳结构的负载型催化剂Ni@Ni–Ir/MgO。经测试所得催化剂具有介孔结构，化学分析其组成为47.8％Ni87.3Ir12.7/53.2mol％MgO。
本实施例的负载型催化剂Ni@Ni–Ir/MgO进行催化剂的耐久性实验(按制氢方法进行循环使用)，结果如图7所示，由图7可以看出：在50℃，Ni@Ni–Ir/MgO催化剂的初始活性和制氢选择性分别为240h–1和100％，经15次循环使用，其活性下降了20％，但制氢选择性几乎不变。
上述实施例为本发明较佳的实施方式，但本发明的实施方式并不受上述实施例的限制，其它的任何未背离本发明的精神实质与原理下所作的改变、修饰、替代、组合、简化，均应为等效的置换方式，都包含在本发明的保护范围之内。

Claims (10)

  1. 一种具有核-壳结构的负载型催化剂，其特征在于：所述催化剂以金属氧化物为载体，以非贵金属为核，以非贵金属和贵金属的合金为壳。
  2. 根据权利要求1所述的一种具有核-壳结构的负载型催化剂，其特征在于：所述的金属氧化物是指具有介孔结构的金属氧化物。
  3. 根据权利要求1或2所述的一种具有核-壳结构的负载型催化剂，其特征在于：所述的金属氧化物是指氧化镁、氧化镧、氧化铈或氧化铕；所述的非贵金属是指铁、钴或镍；所述的贵金属是指钌、铑、钯、依或铂。
  4. 权利要求1～3任一项所述的一种具有核-壳结构的负载型催化剂的制备方法，其特征在于包括以下制备步骤：
    (1)共沉淀法制备负载型非贵金属前驱体：
    将沉淀剂在30～60℃和搅拌下，逐滴加入含非贵金属可溶性盐和载体金属可溶性盐的醇溶液中，反应1～2h，然后在80～100℃和密封条件下反应8～12h，离心分离沉淀，沉淀在30～60℃条件下干燥8～12h，然后在空气气氛和400～600℃条件下烧结1～4h，最后在流动H2气氛和300～600℃条件下还原1.5～3h，即得负载型非贵金属前驱体；
    (2)置换法制备具有核-壳结构的负载型催化剂：
    在室温及搅拌条件下，将步骤(1)的负载型非贵金属前驱体置于贵金属的均相溶液中进行第一次置换反应，离心分离沉淀，将沉淀进行洗涤干燥后进行第一次烧结，然后置于贵金属的均相溶液中进行第二次置换反应，经洗涤干燥后进行第二次烧结，即得具有核-壳结构的负载型催化剂。
  5. 根据权利要求4所述的一种具有核-壳结构的负载型催化剂的制备方法，其特征在于：步骤(1)中所述的沉淀剂是指四甲基氢氧化铵的乙醇或甲醇溶液；所述的醇溶液是指乙醇溶液或甲醇溶液；所述的非贵金属可溶性盐是指 Ni(NO3)2、Fe(NO3)3或Co(NO3)2；所述的载体金属可溶性盐是指La(NO3)3、Ce(NH4)2(NO3)6、Eu(NO3)3或Mg(NO3)2；步骤(2)中所述的贵金属的均相溶液是指H2PtCl6水溶液、K2PtCl6水溶液、RhCl3水溶液、K2PdCl4水溶液或H2IrCl6水溶液。
  6. 根据权利要求4所述的一种具有核-壳结构的负载型催化剂的制备方法，其特征在于：步骤(2)中所述的第一次置换反应中贵金属的均相溶液所含的贵金属元素与负载型非贵金属前驱体所含的非贵金属元素的摩尔比为1:(10～80)；所述的第二次置换反应中贵金属的均相溶液所含的贵金属元素与负载型非贵金属前驱体中所含的非贵金属元素的摩尔比为1:(5～8)。
  7. 根据权利要求6所述的一种具有核-壳结构的负载型催化剂的制备方法，其特征在于：步骤(2)中所述的第一次置换反应中贵金属的均相溶液所含的贵金属元素与负载型非贵金属前驱体所含的非贵金属元素的摩尔比为1：18；所述的第二次置换反应中贵金属的均相溶液所含的贵金属元素与负载型非贵金属前驱体中所含的非贵金属元素的摩尔比为1：8。
  8. 根据权利要求4所述的一种具有核-壳结构的负载型催化剂的制备方法，其特征在于：步骤(2)中所述的第一次烧结和第二次烧结是指在流动的H2气氛和200～600℃温度条件下烧结2～4h。
  9. 根据权利要求8所述的一种具有核-壳结构的负载型催化剂的制备方法，其特征在于：步骤(2)中所述的第一次烧结和第二次烧结是指在流动的H2气氛和350～400℃温度条件下烧结2～4h。
  10. 权利要求1～3任一项所述的一种具有核-壳结构的负载型催化剂在水合肼催化分解制氢中的应用，其特征在于：在所述负载型催化剂的催化作用下，含N2H4·H2O的燃料液分解得到H2。
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Families Citing this family (7)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101664685A (zh) * 2009-09-27 2010-03-10 西北师范大学 低铂高活性核-壳结构催化剂及其制备方法
US20100197490A1 (en) * 2004-12-22 2010-08-05 Brookhaven Science Associates, Llc Platinum-Coated Non-Noble Metal-Noble Metal Core-Shell Electrocatalysts
CN102500365A (zh) * 2011-10-19 2012-06-20 华南理工大学 一种用于低温燃料电池的核壳结构催化剂的制备方法
CN104857973A (zh) * 2015-04-28 2015-08-26 华南理工大学 一种具有核-壳结构的负载型催化剂及其制备方法与应用

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100409943C (zh) * 2005-07-28 2008-08-13 大连理工大学 一种化学置换法制备纳米贵金属加氢催化剂的方法及应用
CN102903939A (zh) * 2012-10-17 2013-01-30 厦门大学 一种非铂核-壳结构燃料电池催化剂及其制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100197490A1 (en) * 2004-12-22 2010-08-05 Brookhaven Science Associates, Llc Platinum-Coated Non-Noble Metal-Noble Metal Core-Shell Electrocatalysts
CN101664685A (zh) * 2009-09-27 2010-03-10 西北师范大学 低铂高活性核-壳结构催化剂及其制备方法
CN102500365A (zh) * 2011-10-19 2012-06-20 华南理工大学 一种用于低温燃料电池的核壳结构催化剂的制备方法
CN104857973A (zh) * 2015-04-28 2015-08-26 华南理工大学 一种具有核-壳结构的负载型催化剂及其制备方法与应用

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* Cited by examiner, † Cited by third party
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