All-pH-Tolerant\nIn-Plane Heterostructures for Efficient\nHydrogen Evolution Reaction

Abstract

Generally,\nelectrocatalytic hydrogen evolution reaction (HER) by\nwater splitting is a pH-dependent reaction, which limits the widespread\nharvesting of hydrogen energy. Herein, we present a simple way for\nchemical bonding of MoS₂ (002) planes and α-MoC {111}\nplanes to form in-plane heterostructures capable of efficient pH-universal\nHER. Due to the lattice strain from mismatched lattice parameters\nbetween α-MoC and MoS₂, this catalyst changes the\nelectronic configuration of the MoS₂ and thus acquires\nthe favorable proton adsorption and desorption activity, suggested\nby the platinum (Pt)-like free Gibbs energy. Consequently, only a\nlow 78 mV overpotential is needed to achieve the current density of\n10 mA cm^–2 in acidic solution along with a favorable\nTafel kinetic process with a Tafel slope of 38.7 mV dec^–1. Owing to the synergistic interaction between MoS₂ (002)\nplanes and α-MoC {111} planes with strong water dissociation\nactivities, this catalyst also exhibits high HER performances beyond\nthat of Pt in neutral and alkaline. This work proves the advances\nof in-plane heterostructures and illustrates the production of low-cost\nbut highly efficient pH-universal HER catalytic materials, promising\nfor future sustainable hydrogen energy.