In situ reconstruction of defect-engineered bimetallic (DA)Ni/Mo–MOFs@TiO2 generates an anion-protected active hydroxides via: Towards corrosion-resistant seawater photoelectrolysis for hydrogen production

Photoelectrochemical (PEC) seawater splitting offers a sustainable route for hydrogen production; however, it is challenged by the corrosion and sluggish kinetics of photoanodes in chloride-rich electrolytes. To overcome this, we developed a bimetallic metal-organic framework (MOFs) structure with oxygen vacancies (O V ) on TiO 2 nanorods, denoted as (DA)Ni/Mo–MOFs@TiO 2 . This photoanode achieved a high photocurrent density of 2.21 mA·cm −2 and H 2 production rate of 36.07 μmol·cm −2 ·h −1 in real seawater. Notably, it undergoes in situ reconstruction during the oxygen evolution reaction (OER), forming catalytically active Ov–NiOOH accompanied by a protective MoO 4 2− layer. In situ Raman and X-ray photoelectron spectroscopy (XPS) directly revealed the reconstruction process and interfacial adsorption. Density functional theory (DFT) calculations further demonstrated that the reconstructed surface selectively stabilized *OH intermediates (E ad  = −4.26 eV), thereby enhancing the OER selectivity and corrosion resistance. This system demonstrated exceptional stability, exhibiting minimal faradaic efficiency loss (1.2–2.3%) in high chloride ion environments (0.7–1 mol/L NaCl). This study provides a novel strategy for designing durable photoelectrodes via pre-catalyst reconstruction.