CuWO₄ is a medium bandgap (2.3 eV) n-type semiconductor capable of photoelectrochemical water oxidation under applied electrical bias. Here, we show for the first time that suspended microcrystals CuWO₄ evolve oxygen photocatalytically under visible illumination from solutions of 0.05 M AgNO₃ (10.8 μmol/hour; AQE of 0.56% at 400 nm) and 0.0002 M FeCl₃ (1.5 μmol/hour). No oxygen is detected with 0.002 M [Fe(CN)₆]³⁻ as sacrificial agent. The activity dependence on the redox potential of the acceptors is due to the presence of Cu²⁺ based electron trap states in CuWO₄. According to surface photovoltage spectroscopy and electrochemistry, these states are located on the particle surface, 1.8 eV above the valence band edge of the material. Controlling the chemistry of these states will be key to uses of CuWO₄ particles in tandem catalysts for overall water splitting.

中文翻译：

---

表面态在CuWO4颗粒光催化氧释放中的作用

CuWO ₄是一种中带隙（2.3 eV）n型半导体，能够在施加的电偏压下进行光电化学水氧化。在这里，我们首次显示出悬浮的微晶CuWO ₄在可见光下从0.05 M AgNO ₃（10.8μmol/小时； AQE在400 nm下为0.56％）和0.0002 M FeCl ₃（1.5μmol/小时）的溶液中光催化释放氧。）。使用0.002 M [Fe（CN）₆ ] ^3-作为牺牲剂，未检测到氧。活度依赖于受体的氧化还原电位是由于在CuWO _4中存在基于Cu ²⁺的电子陷阱态。根据表面光电压光谱和电化学，这些状态位于粒子表面，在材料的价带边缘上方1.8 eV。控制这些状态的化学性质将是在串联催化剂中使用CuWO ₄颗粒进行整体水分解的关键。