Charge Transfer Engineering via Multiple Heteroatom Doping in Dual Carbon-Coupled Cobalt Phosphides for Highly Efficient Overall Water Splitting

The exploration of non-noble-metal bifunctional electrocatalysts with high activity and stability for overall water splitting is crucial, but remains challenging for hydrogen fuel production. Herein, tuning of the charge transfer ability and catalytic performance of zeolitic imidazolate framework-derived porous carbon/reduced graphene oxide-coupled CoP composites (CoP@C@rGO) was achieved by incorporating multiple heteroatoms. The combined experimental investigation and density functional theory calculations revealed that the electronic interaction within the composites caused by B, N, and S tri-doped heteroatoms effectively induced interfacial charge transfer, which improved the active site accessibility and reduced the energy barriers of the intermediates. From the synergetic effects of the components, the overall water splitting electrolyzer assembled using the newly prepared B,N,S-CoP@C@rGO catalyst required only 1.50 V to drive a current density of 10 mA cm(-2), which is superior to the commercial Pt/C and IrO2/C couple (1.56 V).