Multi Interface-Enhanced Ni(Fe)P/Ni(Fe)OOH/MXene Catalysts for Efficient Alkaline Electrolysis

Abstract

Electrochemical water electrolysis for hydrogen production offers a feasible way for renewable energy development but still faces significant challenges. Developing high-performance catalysts with high activity, low cost, long-term stability, corrosion resistance, and antisediment aggregation is crucial for the practical application of water electrolysis, particularly seawater electrolysis. For this purpose, we designed a Ni(Fe)P/Ni(Fe)OOH/MXene composite electrocatalyst on an iron foam substrate, which uses a multi-interface structure, Fe self-doping, and incomplete phosphating to jointly adjust the electronic structure and optimize H* absorption. Importantly, the incorporation of MXene significantly enhances electrical conductivity, increases the exposure sites, and facilitates gas release, thereby boosting the hydrogen evolution reaction (HER) performance. Meanwhile, the self-doping of the substrate and vertically staggered nanosheet morphology induced by MXene are utilized to enhance the bonding between the catalyst and substrate, as well as the antisediment aggregation performance, thereby achieving long-term stable operation in an alkaline seawater environment. Consequently, the catalyst demonstrates outstanding HER behavior, achieving 100 mA cm–2 at 140 mV in freshwater and 165 mV in seawater, while maintaining stability for 45 h. Moreover, Ni(Fe)P/Ni(Fe)OOH/MXene was assembled with Fe-Ni(OH)2 into a dual-electrode electrolysis cell, achieving 10 mA cm–2 at only 1.49 V in freshwater, and 1.56 V in natural seawater. This work may open up a prospect for freshwater electrolysis of high efficiency HER catalyst.