In situ formation of Ni3Se4 nanorod arrays as versatile electrocatalysts for electrochemical oxidation reactions in hybrid water electrolysis

Abstract

Water splitting is limited by the sluggish kinetics of anodic oxygen evolution, thus extensive studies have focused on developing highly efficient electrocatalysts for water oxidation. Nevertheless, replacing sluggish water oxidation with smart anodic reactions would greatly lower the overall cost of energy and the electrode by using earth-abundant electrocatalysts. Herein, a Ni₃Se₄ nanorod array is prepared by an in situ hydrothermal selenization method and demonstrates excellent activity for anodic reactions. Assisted by this versatile Ni₃Se₄ nanorod array, only 240 mV overpotential is required to drive 10 mA cm⁻² of oxygen evolution current steadily. By substituting oxygen evolution with urea and hydrazine oxidation, the anodic potential can be reduced from 1.47 V to 1.38 V and even further to 0.32 V to afford 10 mA cm⁻² anodic current density. Substituting anodic reactions coupled with the non-precious electrocatalyst demonstrated in the hybrid water electrolysis in this study has promising potential for future energy conversion, environmental treatment and valuable chemical upgrading.