A novel metal/semiconductor photocatalyst, Cu nanoparticles (NPs) modified TiO₂ hollow spheres (Cu/TiO₂), was designed for efficient photocatalytic overall water splitting (POWS) under both ultraviolet (UV) and visible (Vis) light. This Cu/TiO₂ photocatalyst possesses excellent POWS performance under Vis light at the highest level among the reported TiO₂-based photocatalysts. Interestingly, the metal/semiconductor junction formed between Cu and TiO₂ enables controlled water-oxidation product selectivity (H₂O₂ or O₂) via different reaction pathways regulated by irradiation wavelengths. Under UV light, the electrons excited in TiO₂ are captured by Cu NPs through the Cu/TiO₂ Schottky interface for H₂ production, with the photoholes in TiO₂ producing H₂O₂ through a two-electron process; whilst under Vis light, Cu NPs act as plasmon to inject hot electrons to TiO₂ for H₂ production, while O₂ is produced by hot holes on Cu NPs via a four-electron process. This rational design of function-switchable metal/semiconductor junction may be helpful to understand the mechanisms for POWS with desired gas/liquid water-oxidation products.

一种新型金属/半导体光催化剂，Cu 纳米颗粒 (NPs) 修饰的 TiO ₂空心球 (Cu/TiO ₂ )，旨在用于在紫外 (UV) 和可见光 (Vis) 光下进行高效的光催化全水分解 (POWS)。这种Cu/TiO _{2光催化剂在可见光下具有优异的POWS性能，在已报道的TiO 2}基光催化剂中处于最高水平。_{有趣的是，在 Cu 和 TiO 2}之间形成的金属/半导体结能够通过由照射波长调节的不同反应途径来控制水氧化产物的选择性（H ₂ O ₂或 O _{2 ）。}在紫外光下，TiO2 中的电子被激发₂通过Cu/TiO ₂肖特基界面被Cu NPs捕获以产生H ₂，TiO ₂中的光孔通过双电子过程产生H ₂ O _{2 ；}而在可见光下，Cu NPs 作为等离子体将热电子注入 TiO ₂以产生 H ₂，而 O ₂则通过四电子过程由 Cu NPs 上的热空穴产生。这种功能可切换的金属/半导体结的合理设计可能有助于理解 POWS 与所需气体/液体水氧化产物的机制。