Electrodeposited Rhodium Phosphide with High Activity for Hydrogen Evolution Reaction in Acidic Medium

Development of high-performance electrodes for water electrolyzers is an urgent research task to realize clean hydrogen production from renewable energies. Pt is known as the best cathode for the hydrogen evolution reaction, but its high cost and scarcity limit the commercial use of water electrolyzers in practical applications. As an alternative, we report an effective way to fabricate Rh and Rh-P catalysts on a carbon paper substrate via simple electrodeposition at room temperature and under ambient pressure. Under the optimized deposition parameters, such as potential and time, a certain facet highly populated at the surface of Rh electrodes demonstrated high intrinsic activity for hydrogen evolution in an acidic electrolyte. Further enhancement of the catalyst performance was achieved by a modified electronic structure of Rh-P electrodes, and the intrinsic and mass activity obtained exceeded those of Pt electrodes. The electrode reported herein can thus potentially replace the commercial Pt electrode as the cathode in a water electrolyzer.