Mo2C‐Based Ceramic Electrode with High Stability and Catalytic Activity for Hydrogen Evolution Reaction at High Current Density

Abstract

AbstractDeveloping robust electrodes with high catalytic performance is a key step for expanding practical HER (hydrogen evolution reaction) applications. This paper reports on novel porous Mo2C‐based ceramics with oriented finger‐like holes directly used as self‐supported HER electrodes. Due to the suitable MoO3 sintering additive, high‐strength (55 ± 6 MPa) ceramic substrates and a highly active catalytic layer are produced in one step. The in situ reaction between MoO3 and Mo2C enabled the introduction of O in the Mo2C crystal lattice and the formation of Mo2C(O)/MoO2 heterostructures. The optimal Mo2C‐based electrode displayed an overpotential of 333 and 212 mV at 70 °C under a high current intensity of 1500 mA cm−2 in 0.5 m H2SO4 and 1.0 m KOH, respectively, which are markedly better than the performance of Pt wire electrode; furthermore, its price is three orders of magnitude lower than Pt. The chronopotentiometric curves recorded in the 50 – 1500 mA cm−2 range, confirmed its excellent long‐term stability in acidic and alkaline media for more than 260 h. Density functional theory (DFT) calculations showed that the Mo2C(O)/MoO2 heterostructures has an optimum electronic structure with appropriate *H adsorption‐free energy in an acidic medium and minimum water dissociation energy barrier in an alkaline medium.