As an ideal candidate for photocatalytic overall water splitting, Sn₃O₄ only be active with the help of hole sacrificial agent. In this work, we reveal the corresponding mechanism and provide a feasible strategy based on surface polarization. The results show that the Sn(II) in Sn₃O₄ would trap the holes and then be oxidized during water splitting, leading to photocorrosion and weak oxygen evolution activity. The phosphoric acid modification could enhance the activity of Sn₃O₄ for oxygen evolution, and overall water splitting is achieved accordingly. The hydrogen and oxygen evolution rates can reach up to 9.6 and 4.5 μmol g⁻¹ h⁻¹, respectively. It is mainly due to the modified phosphate groups could make Sn₃O₄ carry more negative charges by ionization in water. The generated surface electric field could weaken the trapping effect, thus the holes can arrive at the surface effectively, along with improved stability and charge carrier separation.

作为光催化全分解水的理想候选者，Sn ₃ O ₄仅在空穴牺牲剂的帮助下才具有活性。在这项工作中，我们揭示了相应的机制并提供了一种基于表面极化的可行策略。结果表明，Sn ₃ O ₄中的Sn(II)会捕获空穴，然后在水分解过程中被氧化，导致光腐蚀和弱析氧活性。磷酸改性可以提高Sn ₃ O ₄的析氧活性，从而实现整体水分解。析氢和析氧速率可达 9.6 和 4.5 μmol g ^-1 h ^-1， 分别。这主要是由于修饰的磷酸基团可以使Sn ₃ O ₄通过在水中电离而带更多的负电荷。产生的表面电场可以减弱俘获效应，因此空穴可以有效地到达表面，同时提高稳定性和电荷载流子分离。