Photocatalysts with the photocatalytic “memory” effect could resolve the intrinsic activity loss of traditional photocatalysts when the light illumination is turned off. Due to the dual requirements of light absorption and energy storage/release functions, most previously reported photocatalysts with the photocatalytic “memory” effect were composite photocatalysts of two phase components, which may lose their performance due to gradually deteriorated interface conditions during their applications. In this work, a simple solvothermal process was developed to synthesize Bi₂WO₆ microspheres constructed by aggregated nanoflakes. The pure phase Bi₂WO₆ was found to possess the photocatalytic “memory” effect through the trapping and release of photogenerated electrons by the reversible chemical state change of W component in the (WO₄)²⁻ layers. When the illumination was switched off, Bi₂WO₆ microspheres continuously produced H₂O₂ in the dark as those trapped photogenerated electrons were gradually released to react with O₂ through the two-electron O₂ reduction process, resulting in the continuous disinfection of Escherichia coli bacteria in the dark through the photocatalytic “memory” effect. No deterioration of their cycling H₂O₂ production performance in the dark was observed, which verified their stable photocatalytic “memory” effect.

当光照明关闭时，具有光催化“记忆”效应的光催化剂可以解决传统光催化剂的固有活性损失。由于对光吸收和能量存储/释放功能的双重要求，大多数先前报道的具有光催化“记忆”效应的光催化剂是两相成分的复合光催化剂，由于在使用过程中界面条件逐渐恶化，它们可能会失去其性能。在这项工作中，开发了一种简单的溶剂热工艺来合成由聚集的纳米薄片构成的Bi ₂ WO ₆微球。纯相Bi ₂ WO ₆发现通过（WO ₄）²⁻层中W组分的可逆化学状态变化，通过捕获和释放光生电子而具有光催化“记忆”效应。当关闭照明时，Bi ₂ WO ₆微球在黑暗中连续产生H ₂ O ₂，因为被捕获的光生电子逐渐释放出来，并通过二电子O ₂还原过程与O ₂反应，导致对O ₂的连续消毒。大肠杆菌在黑暗中通过光催化“记忆”效应。骑车H ₂不变在黑暗中观察到了O _2的生产性能，这证明了其稳定的光催化“记忆”效应。