Reaction-Induced Restructuring of 2D MoS ₂ to MoC _<i>x</i> 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 MoCx 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 MoCx nanostructures, while conventional ML-MoS2 undergoes incomplete transformation. The resulting MoCx 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/gcatal·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.