Enhanced Electrochemical Oxygen Evolution Reaction on Hydrogen Embrittled CoSe Surface

Abstract In the design of structurally competent electrodes with prolonged lifecycles, a solid understanding of the gaseous hydrogen interaction in a metal lattice is highly desirable. During hydrogen evolution reaction, ingress of H severely affects the physical and mechanical properties of the material causing catastrophic brittle failures (hydrogen embrittlement). In this work, by chronoamperometry technique, an electrode with CoSe catalyst system is intentionally diffused with H to serve as a hydrogen stressed CoSe electrode. Surprisingly this H‐embrittled CoSe electrode exhibits enhanced oxygen evolution reaction (OER) behavior as confirmed by linear sweep voltammetry (LSV), impedance, and Tafel analysis, a cathodic shift of 80 mV at the current density of 10 mA cm −2 , impedance analysis reveals half the time of R ct decreasing in the OER on H‐embrittled CoSe than pristine CoSe. The Tafel slope of the H‐embrittled CoSe exhibits of 30 mV, which is relatively lower than the pristine CoSe at OER condition. These results collectively support the enhanced activity of the H‐embrittled CoSe electrode towards OER. Diffusion of hydrogen into metal lattice is confirmed by the high‐resolution transmission electron microscopy (HR‐TEM) fringes analysis, where a 22% decrease Q2 in the lattice distance is revealed by the H‐embrittled CoSe catalyst.