Interfacial engineering of CoP/CoS₂ heterostructure for efficiently electrocatalytic pH-universal hydrogen production

The design and development of high-performance, low-cost catalysts with long-term durability are crucial for hydrogen generation from water electrolysis. Interfacial engineering is an appealing strategy to boost the catalytic performance of electrode materials toward hydrogen evolution reaction (HER). Herein, we report a simple phosphidation followed by sulfidation treatment to construct heterogeneous cobalt phosphide-cobalt sulfide nanowire arrays on carbon cloth (CoP/CoS₂/CC). When evaluated as catalysts toward the HER, the resultant CoP/CoS₂/CC exhibits efficient pH-universal hydrogen production due to the heterostructure, synergistic contribution of CoP and CoS₂, and conductive substrate. To attain a current density of 10 mA cm^-2, overpotentials of only 111.2, 58.1, and 182.9 mV for CoP/CoS₂/CC are required under alkaline, acidic, and neutral conditions, respectively. In particular, the as-prepared CoP/CoS₂/CC shows markedly improved HER electroactivity in 1.0 M KOH, even outperforming commercial Pt-C/CC at a current density of >50 mA cm^-2. In addition, the self-assembled CoP/CoS₂||NiFe layered double hydroxide electrolyzer demonstrates efficient catalytic performance and long-time stability, excelling the benchmark Pt-C||IrO₂. These findings indicate an effective pathway for the fabrication of high-performance heterogeneous electrocatalysts for hydrogen production in the future.