All-pH-Tolerant In-Plane Heterostructures for Efficient Hydrogen Evolution Reaction.

Cheng, Zhihua; Xiao, Yukun; Wu, Wenpeng; Zhang, Xinqun; Fu, Qiang; Zhao, Yang; Qu, Liangti · ACS Nano · 2021

basic_science · Level V

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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 MoS<sub>2</sub> (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 MoS<sub>2</sub>, this catalyst changes the electronic configuration of the MoS<sub>2</sub> 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<sup>-2</sup> in acidic solution along with a favorable Tafel kinetic process with a Tafel slope of 38.7 mV dec<sup>-1</sup>. Owing to the synergistic interaction between MoS<sub>2</sub> (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.