Photochemical water oxidation in the presence of a Ru(II) photosensitizer to form O₂ is one of the most studied reactions in (photo)catalysis for both homogeneous and heterogeneous systems. In the present work, several Ru(II)-tris-diimine-type complexes with different ligands were used under a wide pH range (3.7–9.4) and over different transition-metal oxide (MO_x) catalysts to reveal the factors that govern the O₂ evolution activity. Most importantly, the results clarified that a certain “threshold” potential determines whether water oxidation can proceed and that this potential is related to the energy barrier for electron transfer from the MO_x catalyst to the Ru(II) photosensitizer. The results of this work highlight that the potential of the electrons involved in the water oxidation on MO_x catalysts can be estimated through the simple application of a photochemical reaction, which will be a useful measure for assessing the water oxidation activity of suspended nanoparticle catalysts.

中文翻译：

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发现使用 Ru（II） 光敏剂和 MOx 催化剂触发光化学水氧化的阈值电位


在 Ru（II） 光敏剂存在下形成 O₂ 的光化学水氧化是均相和非均相体系的（光）催化中研究最多的反应之一。在本工作中，在较宽的 pH 范围 （3.7–9.4） 和不同的过渡金属氧化物 （MO_x） 催化剂下使用几种具有不同配体的 Ru（II）-三三亚胺型络合物，以揭示控制 O₂ 析出活性的因素。最重要的是，结果阐明了一定的“阈值”电位决定了水氧化是否可以进行，并且该电位与电子从 MO_x 催化剂转移到 Ru（II） 光敏剂的能垒有关。这项工作的结果强调，可以通过简单的光化学反应来估计 MO_x 催化剂上参与水氧化的电子的电位，这将是评估悬浮纳米颗粒催化剂的水氧化活性的有用措施。