A kind of supported catalyst with core-shell structure and its preparation method and application

Abstract

The present invention relates to the technical field of catalytic materials. Disclosed are a supported catalyst having a core-shell structure, a preparation method therefor, and an application thereof. The preparation method for the catalyst comprises: co-precipitating an alcoholic solution of a non-noble metal soluble salt and a supporter metal soluble salt under the action of a precipitant, sintering and reducing a precipitate so as to obtain a supported non-noble metal precursor, and then performing replacement reaction and sintering reaction on the supported non-noble metal precursor and a homogeneous solution of noble metal twice so as to obtain a supported catalyst in which a mesoporous metal oxide serves as a supporter, non-noble metal serves as a core and an alloy of the non-noble metal and the noble metal serves as a shell. The catalyst of the present invention forms a supported core-shell structure, an alloy of thin non-noble metal and noble metal serving as a shell. Thus, the usage of noble metal can be significantly reduced, the production cost of the catalyst is reduced, and in a catalytic decomposition hydrogen production process of a hydrazine hydrate, the catalyst has good catalysis efficiency and hydrogen production selectivity.

Description

technical field

[0001] The invention belongs to the technical field of catalytic materials, and in particular relates to a supported catalyst with a core-shell structure and a preparation method and application thereof. Background technique

[0002] Hydrazine hydrate (N 2 h 4 ·H 2 O) Hydrogen production by catalytic decomposition is a new integrated hydrogen storage / production technology with promising vehicle / mobile hydrogen source application prospects. Compared with traditional chemical hydrogen storage (such as sodium borohydride, ammonia borane and formic acid) technology The advantages are: high effective hydrogen storage capacity (8wt%), no solid by-products, low cost of hydrogen production, safe and convenient material storage and transportation. The effective hydrogen storage component of hydrazine hydrate is hydrazine (N 2 h 4 ), its decomposition can be carried out according to two competing paths: N 2 h 4 →N 2 +2H 2 , 3N 2 h 4 →4NH 3 +N 2 . From the...

Examples

Embodiment 1

[0050] A supported catalyst Ni@Ni–Pt / La with a core-shell structure in this example 2 o 3 , its preparation method is as follows:

[0051] (1) Co-precipitation method to prepare supported non-noble metal precursor Ni / La 2 o 3 :

[0052] 20mL 2.1M TMAH ethanol solution was added dropwise to 60mL 0.083M Ni(NO 3 ) 2 and 0.17M La(NO 3 ) 3 In the ethanol solution, react for 1h, transfer to the reaction kettle lined with tetrafluoroethylene, react for 12h at 100°C under sealed conditions, and obtain precipitates by centrifugation, dry the precipitates at 60°C for 12h, and then transfer the precipitates into the tube Sintered in an air atmosphere at a temperature of 500 °C for 2 h, and finally in flowing H 2 Atmosphere and 500°C temperature reduction for 1.5h, the supported non-noble metal precursor Ni / La can be obtained 2 o 3 ;

[0053] (2) Preparation of supported catalyst Ni@Ni–Pt / La with core-shell structure by displacement method 2 o 3 :

[0054] Under room tempera...

Embodiment 2

[0071] A supported catalyst Ni@Ni–Pt / La with a core-shell structure in this example 2 o 3 , its preparation method is as follows:

[0072] (1) Co-precipitation method to prepare supported non-noble metal precursor Ni / La 2 o 3 : same as embodiment 1;

[0073] (2) Preparation of supported catalyst Ni@Ni–Pt / La with core-shell structure by secondary replacement method 2 o 3 :

[0074] Under room temperature and magnetic stirring, the supported non-noble metal precursor Ni / La in step (1) 2 o 3 Place in 20mLK 2 PtCl 6 In aqueous solution (adjust K 2 PtCl 6 The concentration of the aqueous solution is such that the molar ratio of Pt element to Ni element in the catalyst is 1:18) to carry out the first displacement reaction, react for 1h, centrifuge and precipitate, and the precipitate is washed with water and alcohol in turn, and dynamic vacuum dried at 30°C for 12h , and then in the flow H 2 Sintered at 350 °C for 2 h in a tube furnace under atmosphere, and then placed ...

Embodiment 3

[0081] A supported catalyst Fe@Fe–Rh / CeO with a core-shell structure in this example 2 , its preparation method is as follows:

[0082] (1) Co-precipitation method to prepare supported non-noble metal precursor Fe / CeO 2 :

[0083] 20mL 1.6M TMAH ethanol solution was added dropwise to 60mL 0.067M Fe(NO 3 ) 3 and 0.067M Ce(NH 4 ) 2 (NO 3 ) 6 In the ethanol solution, react for 2 hours, transfer to a reaction kettle lined with tetrafluoroethylene, and react for 12 hours at 80°C under sealed conditions. The precipitate is obtained by centrifugation, and the precipitate is dried at 30°C for 12 hours, and then the precipitate is transferred to the tube Sintered in an air atmosphere at 400 °C for 4 h, and finally in flowing H 2 Atmosphere and 450°C temperature reduction for 3h, the supported non-noble metal precursor Fe / CeO can be obtained 2 ;

[0084] (2) Preparation of supported catalyst Fe@Fe–Rh / CeO with core-shell structure by displacement method 2 :

[0085] Under roo...

technical field

[0001] The invention belongs to the technical field of catalytic materials, and in particular relates to a supported catalyst with a core-shell structure and a preparation method and application thereof. Background technique

[0002] Hydrazine hydrate (N 2 h 4 ·H 2 O) Hydrogen production by catalytic decomposition is a new integrated hydrogen storage / production technology with promising vehicle / mobile hydrogen source application prospects. Compared with traditional chemical hydrogen storage (such as sodium borohydride, ammonia borane and formic acid) technology The advantages are: high effective hydrogen storage capacity (8wt%), no solid by-products, low cost of hydrogen production, safe and convenient material storage and transportation. The effective hydrogen storage component of hydrazine hydrate is hydrazine (N 2 h 4 ), its decomposition can be carried out according to two competing paths: N 2 h 4 →N 2 +2H 2 , 3N 2 h 4 →4NH 3 +N 2 . From the...

Examples

Embodiment 1

[0050] A supported catalyst Ni@Ni–Pt / La with a core-shell structure in this example 2 o 3 , its preparation method is as follows:

[0051] (1) Co-precipitation method to prepare supported non-noble metal precursor Ni / La 2 o 3 :

[0052] 20mL 2.1M TMAH ethanol solution was added dropwise to 60mL 0.083M Ni(NO 3 ) 2 and 0.17M La(NO 3 ) 3 In the ethanol solution, react for 1h, transfer to the reaction kettle lined with tetrafluoroethylene, react for 12h at 100°C under sealed conditions, and obtain precipitates by centrifugation, dry the precipitates at 60°C for 12h, and then transfer the precipitates into the tube Sintered in an air atmosphere at a temperature of 500 °C for 2 h, and finally in flowing H 2 Atmosphere and 500°C temperature reduction for 1.5h, the supported non-noble metal precursor Ni / La can be obtained 2 o 3 ;

[0053] (2) Preparation of supported catalyst Ni@Ni–Pt / La with core-shell structure by displacement method 2 o 3 :

[0054] Under room tempera...

Embodiment 2

[0071] A supported catalyst Ni@Ni–Pt / La with a core-shell structure in this example 2 o 3 , its preparation method is as follows:

[0072] (1) Co-precipitation method to prepare supported non-noble metal precursor Ni / La 2 o 3 : same as embodiment 1;

[0073] (2) Preparation of supported catalyst Ni@Ni–Pt / La with core-shell structure by secondary replacement method 2 o 3 :

[0074] Under room temperature and magnetic stirring, the supported non-noble metal precursor Ni / La in step (1) 2 o 3 Place in 20mLK 2 PtCl 6 In aqueous solution (adjust K 2 PtCl 6 The concentration of the aqueous solution is such that the molar ratio of Pt element to Ni element in the catalyst is 1:18) to carry out the first displacement reaction, react for 1h, centrifuge and precipitate, and the precipitate is washed with water and alcohol in turn, and dynamic vacuum dried at 30°C for 12h , and then in the flow H 2 Sintered at 350 °C for 2 h in a tube furnace under atmosphere, and then placed ...

Embodiment 3

[0081] A supported catalyst Fe@Fe–Rh / CeO with a core-shell structure in this example 2 , its preparation method is as follows:

[0082] (1) Co-precipitation method to prepare supported non-noble metal precursor Fe / CeO 2 :

[0083] 20mL 1.6M TMAH ethanol solution was added dropwise to 60mL 0.067M Fe(NO 3 ) 3 and 0.067M Ce(NH 4 ) 2 (NO 3 ) 6 In the ethanol solution, react for 2 hours, transfer to a reaction kettle lined with tetrafluoroethylene, and react for 12 hours at 80°C under sealed conditions. The precipitate is obtained by centrifugation, and the precipitate is dried at 30°C for 12 hours, and then the precipitate is transferred to the tube Sintered in an air atmosphere at 400 °C for 4 h, and finally in flowing H 2 Atmosphere and 450°C temperature reduction for 3h, the supported non-noble metal precursor Fe / CeO can be obtained 2 ;

[0084] (2) Preparation of supported catalyst Fe@Fe–Rh / CeO with core-shell structure by displacement method 2 :

[0085] Under roo...

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