Excellent electrocatalytic performance of CuCo2S4 nanowires for high-efficiency overall water splitting in alkaline and seawater media

Abstract

Electrode materials play a key role in enhancing the energy conversion efficiency of catalysts. Therefore, developing cost-effective, non-precious metal electrocatalysts with high catalytic activity for water splitting is crucial. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical for water splitting. Despite their theoretical advantages, ternary metal sulfides face practical limitations, necessitating continuous optimization to fully unlock their potential. In this study, CuCo₂S₄ nanowires are synthesized through a two-step hydrothermal process followed by air annealing. CuCo₂S₄ demonstrates excellent HER performance, with a low overpotential of 86.2 mV in 1 M KOH to achieve a current density of 10 mA cm⁻², which slightly increases to 91.2 mV in 1 M seawater KOH. For the OER, the overpotential decreases from 282.8 mV in KOH to 255.6 mV in seawater. Additionally, the sample exhibits a low cell voltage of 1.7175 V at 50 mA cm⁻². Chronoamperometry tests further confirm its stability.