Synergistic Enhancement of Methanol Formation by Edge-Site FeO_x Clusters and In-Plane Vacancies on MoS₂ for CO₂...

MoS₂ is a promising catalyst for methanol synthesis from CO₂ hydrogenation. It is widely accepted that the in-plane sulfur vacancies are the active sites for methanol formation, while the edge sulfur vacancies catalyze methane formation, which is typically undesirable. Rather than blocking the edge sites with heteroatom dopants, we demonstrate that decorating the edges of MoS₂ with functional FeO_x clusters effectively boost methanol formation via synergy between the RWGS activity of the anchored FeO_x clusters and the CO hydrogenation activity of the in-plane sulfur vacancies. Synthetically, this was achieved by a vacuum impregnation method that chemically anchors FeO_x clusters on the edges of MoS₂, forming stable Fe-S/Fe-O interfaces. With these Fe-S/Fe-O interfaces, the Fe/MoS₂ catalyst shows markedly enhanced methanol selectivity (to 80%) and a high intrinsic space-time-yield (STY) of 0.6 mmol_CH3OH·m^-2·h^-1. In situ spectroscopic and microscopic characterizations combined with theoretical calculations corroborate that the formation of amorphous FeO_x clusters at edge sites of MoS₂ could effectively suppress edge S_v formation, generate additional CO^*, and promote the formation of methanol at the in-plane S_v sites. Broadly speaking, this work has demonstrated the modulation of MoS₂ edge sites using simple and scalable catalyst preparation methods to enhance methanol formation.