Ag₃PO₄ as a novel photoanode material, despite its arguably highest photoactivity, suffers for its poor light absorption and stability for photoelectrochemical (PEC) water oxidation. In this work, 4.5 × 4.5 cm² Ag₃PO₄ microcrystalline films are grown via a room-temperature solution process, and vacuum annealing is proposed to solve the stability and light absorption issues. It is found that the major process below 400 °C of vacuum annealing is the |Recovery| process for Ag₃PO₄ microcrystals, when lattice defects and Ag⁰ surface species get reduced. Next, |Recrystallization| stage occurs at >400 °C. The recovery of native defects of silver vacancies, with both density functional theory calculation and experimental results, could simultaneously improve the light absorption and catalytic activity of Ag₃PO₄. The 400 °C-annealed Ag₃PO₄ photoanode, with enhanced light harvesting and crystal quality, exhibits 88% increase in (J_light − J_dark) value (1.94 mA cm⁻²) than non-annealed photoanode (1.03 mA cm⁻²). Moreover, it retains >99% current density after a 4000-s stability test. These results suggest that vacuum annealing can substantially improve the PEC performance of Ag₃PO₄ microcrystalline film photoanodes due to mitigated effects of native defects, improved light harvesting, and inhibited Ag₃PO₄ decomposition during water oxidation reaction.

Ag ₃ PO ₄作为一种新型光阳极材料，尽管可以说具有最高的光活性，但由于其光吸收性和光电化学（PEC）水氧化稳定性差而受到影响。在这项工作中，4.5 × 4.5 cm ² Ag ₃ PO ₄微晶薄膜通过室温溶液工艺生长，并提出真空退火来解决稳定性和光吸收问题。发现400℃以下真空退火的主要过程是|Recovery|。Ag ₃ PO ₄微晶的工艺，当晶格缺陷和 Ag ⁰表面物种减少。接下来，|重结晶| 阶段发生在 >400 °C。银空位的天然缺陷的恢复，结合密度泛函理论计算和实验结果，可以同时提高Ag ₃ PO ₄的光吸收和催化活性。400 °C 退火的 Ag ₃ PO ₄光阳极具有增强的光收集和晶体质量，与未退火的光阳极（1.03 mA cm ^-）相比，（J_光 -  J_暗）值（1.94 mA cm ^-2）增加了 88% ²）。此外，它在 4000 秒稳定性测试后仍保持 >99% 的电流密度。这些结果表明，真空退火可以显着提高Ag ₃ PO ₄微晶膜光阳极的PEC性能，这是由于减轻了天然缺陷的影响，改善了光收集，并抑制了水氧化反应过程中的Ag ₃ PO ₄分解。