<i>In Situ</i> Anodic Oxidation Tuning of NiFeV Diselenide to the Core–Shell Heterojunction for Boosting Oxygen Evolution

Abstract

Developing non-noble metal-based core-shell heterojunction electrocatalysts with high catalytic activity and long-lasting stability is crucial for the oxygen evolution reaction (OER). Here, we prepared novel core-shell Fe,V-NiSe₂@NiFe(OH)_x heterostructured nanoparticles on hydrophilic-treated carbon paper with high electronic transport and large surface area for accelerating the oxygen evolution rate <i>via</i> high-temperature selenization and electrochemical anodic oxidation procedures. Performance testing shows that Fe,V-NiSe₂@NiFe(OH)<i>_x</i> possesses the highest performance for OER compared to as-prepared diselenide core-derived heterojunctions, which only require an overpotential of 243 mV at 10 mA cm^-2 and a low Tafel slope of 91.6 mV decade^-1 under basic conditions. Furthermore, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) confirm the morphology and elementary stabilities of Fe,V-NiSe₂@NiFe(OH)<i>_x</i> after long-term chronopotentiometric testing. These advantages are largely because of the strong synergistic effect between the Fe,V-NiSe₂ core with high conductivity and the amorphous NiFe(OH)<i>_x</i> shell with enriched defects and vacancies. This study also presents a general approach to designing and synthesizing more active core-shell heterojunction electrocatalysts for OER.