Versatile nanoporous bimetallic phosphides towards electrochemical water splitting

Alloying is an important approach to improving catalytic activities and realizing new functions of heterogeneous catalysts, which has extensively been employed in fabricating noble metal based bimetallic catalysts. However, it is technically unviable in the synthesis of alloyed transition metal compounds, which are emerging as important catalysts for water splitting, in a controllable manner using conventional wet chemical methods. Here we report nanoporous bimetallic (Co_1-xFe_x)₂P phosphides with controllable compositions and tuneable porosity, which are fabricated by the combination of metallurgical alloy design and electrochemical etching. By tailoring the Co/Fe ratios and nanoporosity, the bimetallic phosphides exhibit versatile catalytic activities towards HER and OER in acidic and basic electrolytes. As both the cathode and the anode of an electrolyser, nanoporous (Co_0.52Fe_0.48)₂P shows an outstanding performance in water electrolysis, comparable to the commercial electrolyser with paired Pt/C and IrO₂ catalysts.