Synergistic high-entropy phosphides with phosphorus vacancies as robust bifunctional catalysts for efficient water splitting.

Abstract

High-entropy phosphides (HEPs) have garnered increasing interest as innovative electrocatalysts for water splitting, highlighted by their distinctive catalytic activity, elemental synergy, and tunable electronic configuration. Herein, a novel electrode comprising CoNiCuZnFeP nanocubes with rich phosphorus vacancies was fabricated through coprecipitation and phosphorization two-step method. The synergistic interaction among metal elements and the modulation of the electronic configuration by phosphorus vacancies augmentation enhance the catalytic performance for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The CoNiCuZnFeP catalyst demonstrates overpotentials of 318 mV for HER and 204 mV for OER at 100 mA cm^-2, while maintaining a remarkable durability exceeding 700 h. The catalyst, as the dual-electrode for water electrolysis, requires a voltage of 1.74 V to attain 100 mA cm^-2. Theoretical calculations reveal that the combination of high entropy and phosphorus vacancies can effectively regulate the local charge distribution and electronic characteristics of phosphides, leading to the optimization of adsorption energies and the reduction of the potential energy barrier for water decomposition. This study provides an attractive OER electrocatalyst for renewable hydrogen via efficient water splitting, and paves the way for the design of efficient and stable electrocatalysts with high-entropy materials.