Y. Gao, Y.Y. Xu, H. Guo, J.J. Li, L.L. Ding, T. Wang, J.P. He, K. Chang, * and Z.-S. Wu *

Angewandte Chemie International Edition, 2024, Accepted.

Developing durably active catalysts to tackle harsh potential polarization and seawater corrosion is pivotal for efficient solar-to-hydrogen (STH) conversion, yet remains a challenge. Here we report a durably active catalyst of NiCr-layered double hydroxide (RuldsNiCr-LDH) with highly exposed Ni-O-Ru units, in which Ru is locked at defect lattice site (Rulds) by Ni and Cr. The Cr site electron equilibrium reservoir and Cl- repulsion by intercalated CO32- ensure the highly durable activity of Ni-O-Ru units. OConsequently, our RuldsNiCr-LDH shows ultrastable seawater electrolysis at 200 mA cm-2. Employing RuldsNiCr-LDH both as the anode and cathode, we establish a photovoltaic-electrolysis seawater system to achieve a record 17.73% STH efficiency, corresponding photovoltaic-to-hydrogen  (PTH) efficiency is 72.37%. Further, we elucidate the dynamic evolutionary mechanism involving the interfacial water dissociation-oxidation catalyzed by RuldsNiCr-LDH. Our work is a substantially breakthrough step for achieving economically scalable production of green hydrogen.