All-pH-Tolerant In-Plane Heterostructures for Efficient Hydrogen Evolution Reaction
Zhihua Cheng, Yukun Xiao, Wenpeng Wu, Xinqun Zhang, Qiang Fu, Yang Zhao, Liangti Qu
Abstract
Generally, electrocatalytic hydrogen evolution reaction (HER) by water splitting is a pH-dependent reaction, which limits the widespread harvesting of hydrogen energy. Herein, we present a simple way for chemical bonding of MoS2 (002) planes and α-MoC {111} planes to form in-plane heterostructures capable of efficient pH-universal HER. Due to the lattice strain from mismatched lattice parameters between α-MoC and MoS2, this catalyst changes the electronic configuration of the MoS2 and thus acquires the favorable proton adsorption and desorption activity, suggested by the platinum (Pt)-like free Gibbs energy. Consequently, only a low 78 mV overpotential is needed to achieve the current density of 10 mA cm–2 in acidic solution along with a favorable Tafel kinetic process with a Tafel slope of 38.7 mV dec–1. Owing to the synergistic interaction between MoS2 (002) planes and α-MoC {111} planes with strong water dissociation activities, this catalyst also exhibits high HER performances beyond that of Pt in neutral and alkaline. This work proves the advances of in-plane heterostructures and illustrates the production of low-cost but highly efficient pH-universal HER catalytic materials, promising for future sustainable hydrogen energy.