Construction of Co-Ni3B/GDY heterostructured electrocatalyst for boosting oxygen evolution in alkaline media

Abstract

Water splitting as the clean technology for hydrogen production garnered the widespread attention. The high overpotential required for oxygen evolution reaction (OER) is the central dilemma. Herein, Co-Ni₃B/graphdiyne heterostructure on copper foam (Co-Ni₃B/GDY/CF) was constructed for boosting alkaline OER. Detailed electrochemical analysis showed that Co-Ni₃B/GDY/CF was an exceptional OER electrocatalyst with the low overpotentials of 270 and 335 mV at 20 and 100 mA cm⁻² in 1.0 M KOH solution, respectively, as well as high turnover frequency of 0.80 s⁻¹ at 400 mV. Moreover, its catalytic performance outperformed the benchmarked RuO₂/CF when the current density exceeded 200 mA cm⁻². Importantly, the equipped electrolyser Pt/C/CF||Co-Ni₃B/GDY/CF showed low cell voltage (1.53 V@10 mA cm⁻²) and long-term durability. These results demonstrated that a synergistic effect at the heterointerface between GDY and Co-Ni₃B was achieved, which regulated the electronic configuration, accelerated the charge transfer and increased the active surface areas. Furthermore, the density functional theory calculations revealed that Co-Ni₃B/GDY with incomplete charge transfer lowered the energy barrier of the rate-determining step and optimized adsorption/desorption behavior of the intermediates, thereby effectively promoting O₂ evolution.