The preparation of durable and efficient photoanodes for photoelectrochemical water oxidation is of great importance in promoting the development of green hydrogen production and artificial photosynthesis. Here, n-type BiVO₄ was combined with p-type CuI to construct a CuI/BiVO₄ (CIB-1) p–n heterojunction photoanode. The composite photoanode effectively overcame the drawbacks of BiVO₄, such as low separation and injection efficiency of photogenerated electron–hole pairs. As a result, the CIB-1 had the highest photocurrent density of 1.98 mA cm^–2, which was 2.5 times higher than pure BiVO₄ with 0.79 mA cm^–2 at 1.23 V (vs RHE) under AM 1.5G light irradiation. The CIB-1 had a lower Tafel slope of 23.2 mV decade^–1 compared to 47.9 mV decade^–1 for BiVO₄, so the water oxidation kinetics was remarkably advanced over CuI/BiVO₄. Based on DFT calculations, the OER overpotential of 0.480 V for CuI/BiVO₄ was significantly lower than that of 1.546 V for BiVO₄ due to the lower free energy from OH^– to oxygen over CuI/BiVO₄ compared to BiVO₄.

中文翻译：

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CuI 有效改善 BiVO4 光阳极的热力学和动力学，用于光电化学水氧化


制备耐用高效的光电化学水氧化光阳极，对促进绿色制氢和人工光合作用的发展具有重要意义。在这里，n 型 BiVO₄ 与 p 型 CuI 结合构建了 CuI/BiVO₄ （CIB-1） p-n 异质结光阳极。复合光阳极有效克服了 BiVO₄ 的缺点，例如光生电子-空穴对的分离和注入效率低。因此，CIB-1 具有最高的光电流密度，为 1.98 mA cm^–2，在 AM 1.5G 光照射下，纯 BiVO 4 在 1.23 V （vs RHE） 下为 0.79 mA cm^–2，比纯 BiVO₄ 高 2.5 倍。CIB-1 的塔菲尔斜率较低，为 23.2 mV ^decade-1，而 BiVO₄ 为 47.9 mV ^decade-1，因此水氧化动力学明显优于 CuI/BiVO₄。根据 DFT 计算，CuI/BiVO₄ 的 0.480 V OER 过电位明显低于 BiVO₄ 的 1.546 V，因为与 BiVO₄ 相比，CuI/BiVO₄ 上 ^OH– 对氧的自由能较低。