Self-adaptive interfaces via electrochemical reconstruction enabling efficient PV-PEC water splitting

Abstract

The development of efficient and stable photocathodes remains a central challenge in photoelectrochemical (PEC) water splitting. This study introduces an in situ electrochemical reconstruction strategy that transforms nickel-based catalysts into dynamically adaptive interfaces, overcoming the inherent limitations of static doping in PEC water splitting. Unlike conventional static modifications, this approach enables real-time optimization of active sites under operational conditions via a carbonyl-mediated anchoring mechanism. The prepared InN-based photoelectrodes achieved the record 3.11% solar-to-hydrogen (STH) efficiency, with photocurrent densities of −3.24 mA cm⁻², representing a 3.5-fold improvement over the original device. The applied bias photon-to-current efficiency (ABPE) reached 13.56% at −0.5 V_RHE, significantly exceeding the 1.10% efficiency of the unmodified InN/PM6. In addition, the hydrogen evolution rate is increased to 42.42 µmol h⁻¹ with 80% retention after 12 000 s in alkaline electrolytes. Furthermore, integration into a photovoltaic-PEC (PV-PEC) system yields unassisted water splitting with a 0.95% STH, underscoring its practical potential. This work establishes a transformative paradigm for designing dynamically adaptive interfaces, moving beyond static architectures for advanced solar fuel production.