Dual regulation both intrinsic activity and mass transport for self-supported electrodes using in anion exchange membrane water electrolysis

Abstract

Anion exchange membrane water electrolysis (AEMWE) is considered as a promising approach to large-scale hydrogen production. However, the performance of AEMWE is limited by the slow reaction kinetics of the catalyst and poor mass transport of gases and electrolyte at high current densities. Herein, we report Fe_0.2Ni_0.8-P_0.5S_0.5 nanoisland arrays as an efficient bifunctional catalyst with ultralow overpotentials of 85 mV (for HER) and 180 mV (for OER) to achieve a current density of 10 mA cm⁻². Density functional theory calculations reveal that bimetallic doping of Fe_0.2Ni_0.8-P_0.5S_0.5 effectively improve the intrinsic activity. Particularly, the Fe_0.2Ni_0.8-P_0.5S_0.5 electrode is endowed with superhydrophilicity and aerophobicity, which not only facilitates to the exposure of active sites, but also markedly enhance gas and electrolye diffusion at high current density. Therefore, the AEMWE based on the Fe_0.2Ni_0.8-P_0.5S_0.5 bifunctional electrodes delivers a current density of 2.5 A cm⁻² at 2.0 V. Moreover, the AEMWE maintained long-term operation without obvious performance degradation for 300 h.