Vacancy‐Induced Oxygen Reduction Activity in Janus Transition Metal Dichalcogenides

Abstract In the past few years, transition metal dichalcogenides (TMDs) have attracted extensive attention in the development of oxygen reduction reaction (ORR) catalysts. Herein, a new family of TMDs, Janus TMDs, as ORR catalyst has been investigated by employing the density functional methods. Our results indicated that the pristine Janus TMDs (MoXY, X, Y=S, Se, Te; X≠Y) and MoXY with X vacancy have poor ORR activity. In contrast, MoXY with Mo vacancy, i. e., MoXY‐SV‐Mo are good ORR catalysts due to the moderate adsorption strength of the ORR intermediates. In particular, MoSeS‐SV‐Mo possess the highest ORR activity with a low overpotential of 0.51 V. In addition, the ORR activity is slightly improved under tensile strain, while the compressive strain reduces the ORR activity. These results demonstrated that creating Mo vacancy in MoXY can modulate the ORR activity of Janus TMDs effectively.