Ni-Pt-Co clay catalysts for dry reforming of methane: Influence of trimetallic interfaces and Ce addition

Abstract

Dry reforming of methane (DRM) over Ni-based catalysts is a vital strategy of significant economic and environmental benefits to mitigate the greenhouse effect and facilitate syngas generation, in which catalyst deactivation is the critical bottleneck due to metal sinter and carbon deposition. Herein, a series of NixPt(1-x)Co@0.25C-A (x = 0, 0.25, 0.5, 0.75, 1) catalysts were synthesized and employed in DRM. Results demonstrated that regulating Pt/Co content could induce the formation of Ni-Pt-Co trimetallic alloy interfaces and affect the CH/CO bond cracking ability of as-synthesized catalysts. Ce addition in zeolite pre-crystallization process was favorable to increase the oxygen vacancy (VO) concentration to promote CO2 dissociation and coke removal. In addition, Ce species could strongly interact with the trimetallic alloy sites and skeleton silicon by electron transfer, and thus achieving the strong anchoring effect of clay-based zeolite support on active sites and restricting its sinter and phase segregation. Consequently, Ni0.75Pt0.25Co@0.25C-A catalyst, which equips with the superior Ce-interacted Ni-Pt-Co trimetallic alloy interfaces and high VO concentration as well as abundant surface medium-strength alkaline sites, exhibited the highest CH4/CO2 initial conversion of 80 %/71 % and had 7 % of activity loss after 100 h of long-term stability tests.