A nickel-molybdenum carbide composite catalyst for dry reforming of methane to synthesis gas

Abstract

The invention relates to a nickel-molybdenum carbide composite catalyst for preparing a synthesis gas through dry reforming of methane, and aims at solving the problem that catalyst deactivation is caused by the situation that active components in the conventional nickel-based catalyst and molybdenum-based catalyst are easy to oxidize and sinter during the process of preparing the synthesis gas through dry reforming of methane. The preparation method of the nickel-molybdenum carbide composite catalyst comprises the following steps: a nickel molybdenum oxide precursor is synthesized through a one-step synthesis urea combustion method by adopting the double components, namely nickel and molybdenum; the virgin gas is subjected to dry reforming through methane, and an Ni-Mo2C composite structure is compounded in situ; carbonization-oxidation circulation of Mo2C is established during the process of dry reforming of methane at the same time, so as to obtain the nickel-molybdenum carbide composite catalyst which is sintering-resistant, oxidation-resistant and stable in structure. According to the nickel-molybdenum carbide composite catalyst, the stability and hydrogen selectivity of the process of preparing the synthesis gas through dry reforming of methane are improved; the chemical composition of the catalyst provided by the invention is Nia (Mo2C)b (Al2O3 )c in which the a is 0.09-0.19, the b is 0.03-0.10 and the c is 0.75-0.88.

Description

technical field [0001] The invention relates to a nickel-molybdenum carbide composite catalyst for producing synthesis gas by dry reforming of methane, more specifically, to a nickel-molybdenum carbide composite catalyst synthesized in situ for producing synthesis gas by dry reforming of methane The catalyst of composite phase belongs to the technical field of preparing synthesis gas by methane dry reforming. Background technique [0002] Syngas, i.e. H 2 The mixture of CO and CO can be adjusted by adjusting different hydrogen-carbon ratios (H 2 / CO), used as raw material gas to synthesize methanol, acetic acid and hydrocarbon fuels and other products, and can also be used as fuel for solid oxide fuel cells. Synthesis gas (CH 4 +CO 2 =2CO+2H 2 ), that is, the methane dry reforming process, on the one hand, fully utilizes the two greenhouse gases methane and carbon dioxide, and on the other hand, produces a hydrogen-carbon ratio (H 2 / CO) is close to 1, which provides i...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is that the sintering and oxidation of the catalyst active components that are prone to occur in the existing nickel-based catalyst and molybdenum carbide catalyst in the methane dry reforming process, resulting in the problem of catalyst deactivation, and the use of hydrogen and methane to preheat Carbonization to obtain molybdenum carbide active species has problems such as long carbonization time and cumbersome operation. The present invention uses nickel and molybdenum dual components to synthesize nickel molybdenum oxide precursor by one-step synthesis of urea combustion method, and then dry reforms the raw material gas with methane. In situ temperature programming, the nickel component in the catalyst is used to dissociate methane to generate carbon intermediate species, and in situ convert molybdenum oxide to molybdenum carbide to form Ni-Mo 2 C composite structure while establishing Mo 2 Carbonization-oxidation cycle of C to obtain a Ni-Mo with high specific surface area, sintering resistance, oxidation resistance and stable structure 2 C / Al 2 o 3 Catalysts for dry methane reforming processes

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