Light‐Assisted Anion Exchange Membrane Water and Seawater Electrolysis on a Core–Shell Co‐P@Cu 2 O Catalyst

Harnessing solar energy to assist water and seawater electrolysis represents a promising strategy to reduce the energy input for sustainable hydrogen production, yet its development remains challenging due to limited integration between light‐responsive catalysts and membrane electrolyzer systems. Here, we report a hierarchical core–shell Co‐P@Cu 2 O catalyst that enables efficient light‐assisted hydrogen evolution and is directly interfaced with an anion exchange membrane (AEM) electrolyzer. The Cu 2 O nanowire core serves as a light‐harvesting scaffold, while the Co‐P nanosheet shell provides active sites, collectively enabling strong light absorption, suppressed reflectivity, and efficient photothermal conversion with localized interfacial heating. The interfacial interaction between Co‐P and Cu 2 O facilitates catalytic kinetics, as supported by experimental analyses, while theoretical calculations reveal optimized charge redistribution and a reduced water dissociation barrier. Under one‐sun irradiation, the catalyst achieves overpotentials of 62 and 253 mV at 10 and 500 mA cm −2 , respectively, in 1 M KOH, with activity enhancement predominantly governed by photothermal effects. When integrated into a light‐assisted AEM electrolyzer, the Co‐P@Cu 2 O||NiFe LDH pair delivers efficient and durable overall water and seawater electrolysis at large current densities. This work establishes a viable strategy for coupling photothermal‐assisted electrocatalysis with membrane electrolyzer systems, advancing solar‐assisted hydrogen production from diverse water resources.