Anti-dissolution Pt single site with Pt(OH)(O₃)/Co(P) coordination for efficient alkaline water splitting electrolyzer

As the most well-known electrocatalyst for cathodic hydrogen evolution in water splitting electrolyzers, platinum is unfortunately inefficient for anodic oxygen evolution due to its over-binding with oxygen species and excessive dissolution in oxidative environment. Herein we show that single Pt atoms dispersed in cobalt hydrogen phosphate with an unique Pt(OH)(O₃)/Co(P) coordination can achieve remarkable catalytic activity and stability for oxygen evolution. The catalyst yields a high turnover frequency (35.1 ± 5.2 s⁻¹) and mass activity (69.5 ± 10.3 A mg⁻¹) at an overpotential of 300 mV and excellent stability. Mechanistic studies elucidate that the superior catalytic performance of isolated Pt atoms herein stems from optimal binding energies of oxygen intermediate and also their strong electronic coupling with neighboring Co atoms that suppresses the formation of soluble Pt^x>4 species. Alkaline water electrolyzers assembled with an ultralow Pt loading realizes an industrial-level current density of 1 A cm⁻² at 1.8 volts with a high durability.