Boosting C-O Bond Cleavage and Reverse Water-Gas Shift Activity via Enriched In-Plane Sulfur Vacancies in Single-Layer Molybdenum Disulfide.

The reduction of CO to CO provides a promising approach to the production of valuable chemicals through CO utilization. However, challenges persist with the rapid deactivation and insufficient activity of catalysts. Herein, we developed a soft-hard dual-template method to synthesize layered MoS using inexpensive and scalable templates, enabling facile regulation of sulfur vacancies by controlling the number of layers. The concentration of in-plane vacancies keeps increasing with the reduction of MoS layer number, contributing to 100 % CO selectivity over single-layer MoS and a stable performance over 300-hour reaction at 600 °C. The space-time-yield of CO reached 35.7 g g  h, outperforming most current catalysts. Multiple characterizations and theoretical calculations revealed that in-plane sulfur vacancy sites endowed enhanced production of CO via direct dissociation of CO, showing an intrinsic activity of above 5.8 times higher than that of edge sulfur vacancy sites. The rate-limiting step was shifted from C-O cleavage in edge to sulfur vacancy regeneration in plane with a lower energy barrier. Our findings exemplified the specified design and synthesis of MoS for high-temperature CO reduction through the effective manipulation of distinct vacancy sites, shedding light on their potential industrial application.