Role of Ni-Co bimetals in CaCr2O4 catalysts for dry reforming of methane: Promotion in coke resistance

Dry reforming of methane (DRM) is an efficient way to convert the two main greenhouse gases (CH 4 and CO 2 ) into syngas. This study reported an efficient CaCr 2 O 4 -supported Ni-Co bimetallic catalyst for its DRM activity and anti-coking performance through experiments, characterization, and DFT calculations, with an emphasis on elucidating the role of Ni-Co bimetals in CaCr 2 O 4 catalysts. The results demonstrated that the optimal 13Ni2Co/CaCr 2 O 4 catalyst achieved 94.8 % CH 4 and 96.8 % CO 2 conversions, under conditions of 800 °C and 27,000 mL·h −1 ·g −1 . Characterization results indicated that the alloying effect induced by introducing 2 wt% Co promoted the uniform dispersion of active metals, improved the reducibility and surface basicity of the catalyst, which collectively contributed to its superior catalytic performance. The catalyst also exhibited high thermal stability and excellent coke resistance at 800 °C, with a surface carbon deposition amount of only 0.93 % after 10 h continuous operation. This was attributed to the weak adsorption of surface carbon by Co, thereby reducing the carbon deposition degree. Moreover, the abundant strong basic sites on the surface significantly enhance CO 2 adsorption, while the surface-active adsorbed oxygen further facilitates the elimination of carbon deposits. This research provides valuable insights for the design and development of alloy catalysts in catalytic reaction.