Anchoring platinum clusters in CoP@CoNi layered double hydroxide to prepare high-performance and stable electrodes for efficient water splitting at high current density

Hydrogen production via electrocatalytic water splitting has garnered significant attention, due to the growing demand for clean and renewable energy. However, achieving low overpotential and long-term stability of water splitting catalysts at high current densities remains a major challenge. Herein, a CoP@CoNi layered double hydroxide (LDH) electrode was synthesized via a two-step electrodeposition process, demonstrating oxygen evolution reaction, with an overpotential (ƞ 400 ) of 373 mV and a Tafel slope of 64.2 mV/dec. Subsequently, a superhydrophilic CoP@CoNi LDH-Pt electrode was prepared using an in situ oxidation method, with Pt clusters anchored within the CoP@CoNi LDH for the hydrogen evolution reaction, with an overpotential (ƞ 400 ) of 119 mV and a Tafel slope of 33.6 mV/dec. The CoP@CoNi LDH-Pt||CoP@CoNi LDH system achieved a cell voltage of 1.96 V at 1000 mA/cm 2 , maintaining stable performance after water electrolysis for 160 h. These remarkable outcomes stem from the fast charge transfer, improved mass transfer, and superior stability of the catalysts. Heterostructure electrodes were constructed to optimize the electrocatalytic kinetics through strong interfacial electronic interactions, while superhydrophilic electrodes were fabricated to improve the mass transfer process at a high current density. Anchoring high-activity components in catalysts prevents their detachment during water electrolysis, enhancing the structural stability of the electrodes. This study provides a new approach for large-scale preparation of efficient water electrolysis catalysts and offers significant potential for industrial hydrogen production applications.