Ni-Co alloy catalyst derived from NixCoy/MgAl2O4 via exsolution method for high coke resistance toward dry reforming of methane

Abstract

The dry reforming methane (DRM) reaction, which directly utilizes the two major greenhouse gases as reactants and produces syngas (a mixture of H2 and CO), is a promising method to achieve carbon neutrality. In this study, we developed a series of Ni–Co alloy catalysts with varying ratios using the exsolution method and explored the optimal Ni/Co ratio for DRM. By incorporating Co as a secondary metal and precisely controlling its proportion, the catalysts exhibited improved activation balance in CH4 and CO2, excellent resistance to coking, and the efficiency of the reaction pathway. Notably, the Ni4Co1 catalyst exhibited excellent coke resistance with the lowest coking rate of 0.2 μgcoke·gcat−1h−1, which was only 0.34% of the monometallic Ni catalyst. The origin of coke resistance of catalysts was investigated through in-situ DRIFT and found that the appropriate ratio of Co leads to the formate-intermediate dominant pathway that is more favorable for anti-coking. Furthermore, the catalysts exhibited reversible exsolution properties, as confirmed by cyclic of calcination–reduction. The findings of this study offer valuable insights into the fabrication of high-performance DRM catalysts utilizing the exsolution-driven alloying technique.