Local environment regulation of transition metal dichalcogenide-based single-atom catalysts

Single-atom catalysts have risen significant attention in the realm of green electrocatalytic energy conversion to address energy and environmental sustainability challenges. Transition metal dichalcogenide (TMD)-based single-atom catalysts are considered highly effective in electrocatalysis due to the TMDs' notable specific surface area, tunable elemental species and efficient utilization of single atoms. In order to enhance electrocatalytic performance, it is imperative to elaborately engineer the local environment surrounding the active sites of single atoms within TMDs. In this review, we initially explore the effects of synthesis methods on single-atom active sites and the influence of loading of single atoms on catalytic performance for TMDs. The modulation strategies of the local environment surrounding single-atom sites in TMDs are elaborated, including substitution engineering, surface adsorption, vacancies, spatial confinement and dual-atom site strategies. For each modulation strategy, the effects of diverse local environments on various electrocatalytic applications are presented, such as the oxygen evolution reaction, oxygen reduction reaction, nitrogen reduction reaction, CO₂ reduction reaction and CO oxidation. Ultimately, this study presents a comprehensive overview of the challenges encountered and the potential directions for the advancement of single-atom catalysts based on TMDs in the realm of electrocatalysis. Graphical Abstract: (Figure presented.)