Role and mechanism of calcium-based catalysts for methane dry reforming: A review

Dry reforming of methane (DRM) is a promising and well-studied process that could simultaneously convert the two most abundant greenhouse gases (CH4 and CO2) to syngas (CO and H2). The main obstacle for this reaction, however, is the easy catalyst deactivation caused by coke deposition. Various catalysts have been developed and employed, among which calcium (Ca)-based catalyst is one of the most economically feasible options for industrial scaling-up due to its low cost, easy availability, non-corrosiveness and environmental friendliness. In this paper, therefore, a comprehensive summary of the role and mechanism of Ca-based catalysts in DRM reaction was presented. Specifically, the deactivation behaviors and mechanism of conventional catalysts in DRM reaction were introduced. Subsequently, the role of Ca in various catalyst formulas as a support, a promoter, or a constituent element in specific mineral phases such as perovskites were summarized, and meanwhile the effect of different preparation methods on the performance of Ca-based catalysts was described. As the most widely used agent for CO2 capture, the employment of Ca-based materials in chemical looping dry reforming of methane was also reviewed. Furthermore, the integration of Ca-based catalysts in some novel catalysis systems such as the membrane catalysis and plasma catalysis systems were briefly surveyed. Finally, the future prospects were proposed, in order to provide a guidance for the development and application of Ca-based catalysts in DRM reaction.