Lattice Strain Formation through Spin‐Coupled Shells of MoS2 on Mo2C for Bifunctional Oxygen Reduction and Oxygen Evolution Reaction Electrocatalysts

Abstract Identifying effective means to improve the electrocatalytic performance of transition metal dichalcogenides in alkaline electrolytes is a significant challenge. Herein, an advanced electrocatalyst possessing shells of molybdenum disulfide (MoS 2 ) on molybdenum carbide (Mo 2 C) for efficient electrocatalytic activity in alkaline electrolytes is reported. The strained sheets of curved MoS 2 surround the surface of Mo 2 C, turning the inactive basal planes of MoS 2 into highly active electrocatalytic sites in the alkaline electrolyte. The van der Waals layers, which even possess van der Waals epitaxy along (100) facets of MoS 2 and Mo 2 C, enhance the spin coupling between MoS 2 and Mo 2 C, providing an easy electron transfer path for excellent electrocatalytic activity in alkaline electrolytes and solving the stability issue. In addition, it is found that curved MoS 2 sheets on Mo 2 C show 3.45% tensile strain in the lattice, producing excellent catalytic activity for both oxygen reduction reaction (ORR) (with E 1/2 = 0.60 V vs RHE) and oxygen evolution reaction (OER) (overpotential = 1.51 V vs RHE at 10 mA cm −2 ) with 60 times higher electrochemical active area than pristine MoS 2 . The unique structure and synthesis route outlined here provide a novel and efficient approach toward designing highly active, durable, and cost‐effective ORR and OER electrocatalysts.