Tuning the Electronic Structure of Cobalt–Ruthenium Phosphide Nanosheets for Efficient Overall Water Splitting

Rationally tuning the electronic structure and morphology of catalysts is a vital strategy to boost the catalytic activity. Herein, flower-like cobalt–ruthenium phosphide nanosheets (CoRuP NS) are reported for efficient electrocatalytic overall water splitting. A general principle for precisely modulating the electronic structure of bimetallic phosphate catalysts is developed. The competitive effect between Co and Ru atoms combining with the P atoms is revealed. Hydrogen evolution reaction (HER) activity of CoRuP NS shows a strong interaction with the electron redistribution of the P–metal structure. Benefiting from fully exposed active sites, hierarchical nanostructure, and optimum electron configuration, the CoRuP NS exhibit outstanding HER activity with an overpotential of 54.2 mV at 10 mA cm–2 comparable to that of 20% Pt/C. In addition, the catalysts possess appreciable oxygen evolution reaction (OER) activity with an overpotential of 282.9 mV at 10 mA cm–2. As a result, the CoRuP NS (+) || CoRuP NS (−) cell was constructed, requiring a small voltage of 1.55 V for efficient overall water splitting at 20 mA cm–2. This work provides an innovative strategy for designing bimetallic phosphating phosphate catalysts.