Strained few-layer MoS₂ with atomic copper and selectively exposed in-plane sulfur vacancies for CO₂ hydrogenation to methanol

In-plane sulfur vacancies (S_V) in molybdenum disulfide (MoS₂) were newly unveiled for CO₂ hydrogenation to methanol, whereas edge S_V were found to facilitate methane formation. Thus, selective exposure and activation of basal plane is crucial for methanol synthesis. Here, we report a mesoporous silica-encapsulated MoS₂ catalysts with fullerene-like structure and atomic copper (Cu/MoS₂@SiO₂). The main approach is based on a physically constrained topologic conversion of molybdenum dioxide (MoO₂) to MoS₂ within silica. The spherical curvature enables the generation of strain and S_V in inert basal plane. More importantly, fullerene-like structure of few-layer MoS₂ can selectively expose in-plane S_V and reduce the exposure of edge S_V. After promotion by atomic copper, the resultant Cu/MoS₂@SiO₂ exhibits stable specific methanol yield of 6.11 mol_MeOH mol_Mo^−1 h^−1 with methanol selectivity of 72.5% at 260 °C, much superior to its counterparts lacking the fullerene-like structure and copper decoration. The reaction mechanism and promoting role of copper are investigated by in-situ DRIFTS and in-situ XAS. Theoretical calculations demonstrate that the compressive strain facilitates S_V formation and CO₂ hydrogenation, while tensile strain accelerates the regeneration of active sites, rationalizing the critical role of strain.

Shenghui Zhou, Wenrui Ma, Uzma Anjum, Mohammadreza Kosari, Shibo Xi, Sergey M. Kozlov, Hua Chun Zeng