Sun Wanjun, Liu Jifei, Ran Feitian, Li Na, Li Zengpeng, Li Yuanyuan, Wang Kai
School of New Energy and Power Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu, 730070, China.
Key Laboratory of Solar Power System Engineering, Jiuquan Vocational and Technical College, Jiuquan, 735000, China.
Dalton Trans. 2024 Aug 20;53(33):14018-14027. doi: 10.1039/d4dt01214c.
Metal halide perovskites with suitable energy band structures and excellent visible-light responses have emerged as promising photocatalysts for CO reduction to valuable chemicals and fuels. However, the efficiency of CO photocatalytic reduction often suffers from inefficient separation and sluggish transfer. Herein, a step-scheme (S-scheme) CsPbBr/BiOBr photocatalyst with oxygen vacancies possessing intimate interfacial contact was fabricated by anchoring CsPbBr QDs on BiOBr-Ov nanosheets using a mild anti-precipitation method. The results showed that CsPbBr/BiOBr-Ov-2 with an internal electric field (IEF) heterojunction exhibited a boosted evolution rate of 27.4 μmol g h (CO: 23.8 μmol g h and CH: 3.6 μmol g h) with an electron consumption rate () of 76.4 μmol g h, which was 5.9 and 3.2 times that of single CsPbBr and BiOBr-Ov, respectively. Density functional theory (DFT) calculations revealed that BiOBr with oxygen vacancies can effectively enhance the adsorption and activation of CO molecules. More importantly, infrared Fourier transform spectroscopy (DRIFTS) spectra show the transformation process of the surface species, while the femtosecond transient absorption spectrum (fs-TA) reveals the charge transfer kinetics of the CsPbBr/BiOBr-Ov. Overall, this work provides some guidance for the rational design of S-scheme heterojunctions and vacancy-engineered photocatalysts, which are expected to have potential applications in the fields of photocatalysis and solar energy conversion.
具有合适能带结构和优异可见光响应的金属卤化物钙钛矿已成为将CO还原为有价值的化学品和燃料的有前景的光催化剂。然而，CO光催化还原效率常常受到分离效率低和转移缓慢的影响。在此，采用温和的反沉淀法将CsPbBr量子点锚定在BiOBr-Ov纳米片上，制备了具有紧密界面接触且含有氧空位的阶梯型（S型）CsPbBr/BiOBr光催化剂。结果表明，具有内建电场（IEF）异质结的CsPbBr/BiOBr-Ov-2表现出提高的析出速率，即27.4 μmol g⁻¹ h⁻¹（CO：23.8 μmol g⁻¹ h⁻¹，CH₄：3.6 μmol g⁻¹ h⁻¹），电子消耗速率（）为76.4 μmol g⁻¹ h⁻¹，分别是单一CsPbBr和BiOBr-Ov的5.9倍和3.2倍。密度泛函理论（DFT）计算表明，含有氧空位的BiOBr能有效增强CO分子的吸附和活化。更重要的是，红外傅里叶变换光谱（DRIFTS）光谱显示了表面物种的转化过程，而飞秒瞬态吸收光谱（fs-TA）揭示了CsPbBr/BiOBr-Ov的电荷转移动力学。总体而言，这项工作为S型异质结和空位工程光催化剂的合理设计提供了一些指导，有望在光催化和太阳能转换领域具有潜在应用。
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