Asymmetric Electrolyte Design: Energy-Efficient Electrolytic Hydrogen Production under 0.95 V Driven by Janus Metal Phosphide Nanoarray

Water electrolysis is an environmentally friendly method to produce the promising energy carrier of hydrogen; however, the required high cell voltages restrict its industrial application. Therefore, reducing energy consumption is crucial for large-scale hydrogen production. Except for exploring high-efficiency electrocatalysts, developing energy-saving water electrolysis systems has also attracted increasing attention in recent years. In this work, we report a three-chamber membrane water splitting system with asymmetric acid–base electrolytes driven by two kinds of bifunctional transition-metal phosphide nanoarrays for energy-saving hydrogen production. Experimental results present that this hybrid system just requires voltages below 0.95 V to obtain the overall current density of 10 mA cm–2, which enables a large energy consumption decrease by ∼43% compared to the traditional alkaline water splitting system. In addition, this hybrid system could be well coupled with the solar panel to realize solar-to-hydrogen conversion.