Halide perovskite quantum dots (PQDs) have shown great promise for the photochemical conversion of CO. However, the fast carrier recombination rates and inadequate adsorption/activation for CO molecules have seriously restricted their practical application. Herein, an innovative step-scheme-based CsCuBr/TiO (CCB/TiO) photocatalyst was prepared by embedding CsCuBr PQDs in a mesoporous TiO matrix, which exhibits considerable potential as candidates for CO photoreduction under simulated sunlight. Remarkably, the optimised CCB/TiO photocatalyst delivered an impressive CO reduction activity, which was 3.1 and 16.0 times higher than those achieved by pure CsCuBr and TiO, respectively. Furthermore, the S-scheme charge transfer mode was comprehensively corroborated by density functional theory (DFT) calculations, photo-assisted Kelvin probe force microscopy (KPFM), in situ irradiated X-ray photoelectron spectra (XPS), and electron spin resonance spectroscopy (ESR). On basis of theoretical calculations and in situ diffuse reflectance spectra (DRIFTS), the CCB/TiO exhibited a reduced energy barrier of the rate-determining step, which facilitated the CO photoreduction reaction.

中文翻译：

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嵌入 Cs2CuBr4 钙钛矿量子点的介孔 TiO2 基质作为基于阶梯式的光催化剂，用于促进电荷分离和 CO2 光转化

卤化物钙钛矿量子点（PQD）在CO光化学转化方面显示出巨大的前景。然而，快速的载流子复合速率和对CO分子的吸附/活化不足严重限制了其实际应用。在此，通过将 CsCuBr PQD 嵌入介孔 TiO 基质中，制备了一种基于创新步骤的 CsCuBr/TiO (CCB/TiO) 光催化剂，该催化剂作为模拟阳光下 CO 光还原的候选者表现出巨大的潜力。值得注意的是，优化后的 CCB/TiO 光催化剂具有令人印象深刻的 CO 还原活性，分别比纯 CsCuBr 和 TiO 的还原活性高 3.1 倍和 16.0 倍。此外，S型电荷转移模式得到了密度泛函理论（DFT）计算、光辅助开尔文探针力显微镜（KPFM）、原位辐照X射线光电子能谱（XPS）和电子自旋共振光谱的综合证实。等效串联电阻）。根据理论计算和原位漫反射光谱（DRIFTS），CCB/TiO表现出降低的速率决定步骤的能垒，这有利于CO光还原反应。