关键词: 催化剂, 二氧化碳, 多相反应, 合成气, 核壳结构

Abstract:

Dry reforming of methane can convert two greenhouse gases (CO₂ and CH₄) into syngas, for which traditional supported catalysts suffer from the sintering of metal particles and the carbon deposition, leading to the deactivation. Core-shell structure catalysts can effectively solve the aforementioned problems due to the spatial confinement effect. In this paper, the core-shell structures are classified into three categories, SiO₂ shell layer, Al₂O₃ shell layer and other shell layers, according to the shell type. Current research status is reviewed from the aspects of preparation method, structure-morphology and catalytic characteristic, respectively. The advantages of SiO₂ shell layer are simple preparation, facile adjustment of the thickness and mesoporous structure, and high thermal stability, while Al₂O₃ shell layer can provide alkaline sites to enhance the adsorption and reaction of CO₂ and the CeO₂ shell layer can provide oxygen vacancies to promote the activation of CO₂ and the gasification of accumulated carbon. Finally, this paper proposes several future research directions for core-shell structures, i.e. the expansion and study of shell materials, the investigation of new core-shell structures such as yolk-shell and sandwiches, the precise adjustment of the morphology of core-shell structures and the study of structure-catalysis relationships, and the large-scale preparation for industrial applications.

Key words: catalyst, carbon dioxide, multiphase reaction, syngas, core@shell structure