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

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 Fe0.2Ni0.8-P0.5S0.5 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 Fe0.2Ni0.8-P0.5S0.5 effectively improve the intrinsic activity. Particularly, the Fe0.2Ni0.8-P0.5S0.5 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 Fe0.2Ni0.8-P0.5S0.5 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.

Automated summary

Anion exchange membrane water electrolysis (AEMWE) is a promising method for large-scale hydrogen production, but its performance is limited by catalyst reaction kinetics and mass transport. In this study, Fe0.2Ni0.8-P0.5S0.5 nanoisland arrays are reported as efficient bifunctional catalysts with ultralow overpotentials. The Fe0.2Ni0.8-P0.5S0.5 electrode exhibits superhydrophilicity and aerophobicity, facilitating the exposure of active sites and enhancing gas and electrolyte diffusion. AEMWE based on the Fe0.2Ni0.8-P0.5S0.5 electrodes demonstrates good stability and high efficiency.