Reaction-Induced Restructuring of 2D MoS₂ to MoC_x Nanoclusters for Selective Reverse Water-Gas Shift Reaction

Here, we report the dynamic transformation of few-layered MoS₂ supported on mesoporous SBA-15 (FL-MoS₂/SBA-15) into highly dispersed MoC_x nanoclusters under reverse water-gas shift (RWGS) reaction conditions. Despite a low Mo loading (10 wt %), the in situ carburized catalyst achieves a high CO₂ conversion of 63% at 600 °C, with complete CH₄ suppression and exceptional CO selectivity (∼100%), significantly outperforming classical multilayer MoS₂ (ML-MoS₂) analogues and other references from the literature. Electron paramagnetic resonance (EPR) spectroscopy confirms a high density of sulfur vacancies in the FL-MoS₂ precursor, which facilitates CO₂ activation and promotes carburization reaction: under reaction conditions, carbon incorporation leads to the formation of these catalytically active and selective MoC_x nanostructures, while conventional ML-MoS₂ undergoes incomplete transformation. The resulting MoC_x nanocluster catalyst shows excellent stability, maintaining 63% CO₂ conversion and full CO selectivity over 100 h, at 600 °C and a WHSV of 12,000 mL/g_catal·h. These findings demonstrate the critical role of catalyst precursor nanostructure design and defect engineering in driving structural reactive transformations to achieve selective and stable catalysts.