Dynamic Surface Reconfiguration via Dual-Vacancies Enables High-Efficiency Photoelectrochemical Catalysis for Photo-Enhanced Zinc-Air Batteries

Abstract

Photo-enhanced zinc-air batteries (PZABs) offer a promising approach to coupling solar energy with electrochemical energy conversion, yet their performance remains limited by rapid charge-carrier recombination and insufficient light-harvesting efficiency. Here, we propose a dual-vacancy engineering strategy for NiCrO-based oxides to simultaneously introduce oxygen and chromium vacancies (NCOV-Cr, O). The synergistic effect of these vacancies effectively suppresses carrier recombination, enhances photogenerated electron capture, and promotes the in-situ formation of highly active nickel oxyhydroxide (NiOOH) phases. This structural modulation strengthens the adsorption and activation of *OH intermediates by 1.5 times, providing a stronger thermodynamic driving force for redox processes. As a result, the NCOV-Cr, O photocathode achieves excellent multifunctional catalytic activity with an onset potential of 0.95 V for the ORR, and low overpotentials of 255 and 33 mV for the OER and HER, respectively. When integrated into a PZAB, the device delivers an ultralong cycling life exceeding 450 h and a peak power density of 253.9 mW·cm⁻² under one-sun illumination. This work showcases that tailoring vacancy defects which recombine the ligand coordination environment creates novel avenues for boosting catalytic performance.

Keywords

Photoelectrochemical catalysis / Vacancies / Photo-enhanced zinc-air batteries / Surface reconstruction / OH^– adsorption / Lattice oxygen / Cation leaching / Charge separation

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