Optimization of NiMo alloy nanoparticles for catalytic dry reforming of methane

Metallic Ni nanoparticles doped with Mo are recently developed highly active nanocatalysts for dry reforming of methane (DRM). However, the nature of interactions and co-existence of Ni and Mo, optimal Ni/Mo ratios, as well as the impact of synthetic methods on catalyst structure and activity, remain unclear. This study compares two different synthetic approaches, one-pot synthesis (OP) and post-modification (PM), to determine the optimal Ni/Mo ratio for catalytic performance. The OP method promotes the formation of NiMo nanoparticles under adequate reducing conditions, significantly enhancing DRM activity. In contrast, the PM method ensures precise Ni/Mo ratios but leads to the formation of large MoO₃ nanocrystals that obstruct active sites, thus reducing the catalytic performance. Our findings demonstrate that the highest DRM activity is achieved with a 10:1 molar ratio of Ni/Mo to predominantly form alloy nanoparticles and emphasize that the synthesis method, along with the stoichiometric ratios, plays a crucial role in achieving exceptional catalytic performance.