An efficient pH-universal non-noble hydrogen-evolving electrocatalyst from transition metal phosphides-based heterostructures

The catalytic hydrogen-evolving activities of noble-metal-free catalysts can be greatly enhanced by the crystal structure and components through appropriate interface engineering with anion and cation doped into the catalytic materials. However, the developments of inexpensive electrocatalysts suffer from activity incompatibility with different water sources over a wide pH range. Here we report a promising HER electrocatalyst by hybridizing iron phosphide (FeP4) nanoparticles with highly conductive CoP nanowire arrays (abbreviated as FeP4/CoP) through an in-situ two-step phosphorization process, which exhibits outstanding pH-universal hydrogen-evolving activity in different electrolytes with a wide pH range, featured by extremely low overpotentials of 61, 52 and 37 mV to afford a current density of 10 mA cm−2 in neutral, alkaline and acidic electrolytes, respectively. Especially, the as-prepared FeP4/CoP hybrid exhibits extraordinary catalytic performance and long-term stability at large current densities up to 500 mA cm2 for hydrogen evolution in acidic and alkaline electrolytes, indicating its potential substitute for the practical H2 production. This work represents a simple and low-cost strategy toward rational design and development of all-pH catalysts for pH-universal hydrogen evolution.