Photocatalytic hydrogen evolution from water splitting is an appealing method for producing clean chemical fuels. CuO, with a suitable bandgap, holds promise as a semiconductor for this process. However, the strong photo-corrosion and rapid charge recombination of CuO strongly limit its application in the photocatalytic fields. Herein, an S-scheme heterojunction photocatalyst composed of TiO and CuO was rationally designed to effectively avoid the photo-corrosion of CuO. The introduction of an interfacial nitrogen-doped carbon (NC) layer switches the heterojunction interfacial charge transfer pathway from the p-n to S-scheme heterojunction, which avoids excessive accumulation of photogenerated holes on the surface of CuO. Meanwhile, the hybrid structure shows a broad spectral response (300–800 nm) and efficient charge separation and transfer efficiency. Interestingly, the highest photocatalytic hydrogen evolution rate of TiO-NC-3%CuO-3%Ni is 13521.9 μmol g h, which is approximately 664.1 times higher than that of pure CuO. In-situ X-ray photoelectron spectroscopy and Kelvin probe confirm the charge transfer mechanism of S-scheme heterojunction. The formation of S-scheme heterojunctions effectively accelerates the separation of photogenerated electron-hole pairs and enhances redox capacity, thereby improving the photocatalytic performance and stability of CuO. This study provides valuable insights into the rational design of highly efficient CuO-based heterojunction photocatalysts for hydrogen production.

中文翻译：

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Cu2O-TiO2 光催化剂的界面诱导电荷转移路径从 pn 异质结切换到 S 型异质结，以实现有效的光催化析氢

从水分解中光催化析氢是生产清洁化学燃料的一种有吸引力的方法。 CuO 具有合适的带隙，有望作为该工艺的半导体。然而，CuO的强光腐蚀和快速电荷复合严重限制了其在光催化领域的应用。本文合理设计了由TiO和CuO组成的S型异质结光催化剂，有效避免了CuO的光腐蚀。界面氮掺杂碳（NC）层的引入将异质结界面电荷转移路径从pn异质结转变为S型异质结，避免了光生空穴在CuO表面的过度积累。同时，混合结构表现出宽光谱响应（300-800 nm）和高效的电荷分离和转移效率。有趣的是，TiO-NC-3%CuO-3%Ni的最高光催化析氢速率为13521.9 μmol·gh，比纯CuO高约664.1倍。原位X射线光电子能谱和开尔文探针证实了S型异质结的电荷转移机制。 S型异质结的形成有效加速了光生电子-空穴对的分离，增强了氧化还原能力，从而提高了CuO的光催化性能和稳定性。这项研究为合理设计用于制氢的高效 CuO 基异质结光催化剂提供了宝贵的见解。