Influence of Interface Engineering of the Water Oxidation Electrocatalyst and One-to-One Advantages: High Intrinsic Activity and Solar to Hydrogen Conversion Efficiency

Herein, we adopted the mechanochemical-solvothermal method to prepare embedded nanoplates of CoNiCPs having an amorphous/crystalline phase, presenting a new pathway for developing efficient electrocatalysts in water-splitting technologies at industrially relevant current density. The distinctive morphology of Co4Ni2CPs exhibits a competitive overpotential in GC and NF (301 and 241 mV, respectively), and a smaller Tafel slope (60 and 56 mV dec–1, respectively) than IrO2 (351 and 301 mV; 76 and 74 mV dec–1, respectively). The ultrastability of Co4Ni2CPs for industrial application was established by their durability at 10/100 mA cm–2 (GC-8 h, 1.3%; NF-100 h, 2.0/2.8%), UOR (100 h, 4.6%), SWO (100 h, 3.5%), and overall water splitting (100 h, 2.4%), implying that Co4Ni2CPs have sufficient kinetics to address the elevated rates of the oxygen evolution reaction (OER). Further, the improved OER activity was sustained by Bode analysis at various potentials. The temperature-dependent analysis inferred that the interface in Co4Ni2CPs decreased the activation energy (4.41 kJ mol–1) compared to Co3Ni3CPs (6.68 kJ mol–1) and Co2Ni4CPs (11.04 kJ mol–1). The integrated area of Co4Ni2CPs (0.017415 VA) implied MOOH formation, from which the number of active sites was found to be 0.8614 × 1019. The Co4Ni2CP anode assembled in a full-cell and solar-driven electrolyzer with Pt/C cathode consumed 1.56 V. After the stability test, the nanoplates changed to an amorphous state, which restrains the morphology.