Designing a novel and highly selective photocatalyst for CO₂ photoreduction is of great significance but remains challenging due to problems such as the high recombination rate of photogenerated carriers and the weak reactivity of photocatalyst surfaces. Herein, a dual-defective S-scheme heterostructure of BiOCl with oxygen vacancies and CdS with sulfur vacancies (OV-B/SV-C) was constructed by a two-step solvothermal method. The as-prepared dual-defective composite not only exhibits the maximum CO evolution rate of 272 μL g⁻¹ h⁻¹ without any hole-sacrificing agents and high selectivity for CO evolution (97%), but also shows an excellent Cr(VI) photoreduction performance within 60 s. Experimental characterization and DFT results indicate that dual-defective introduction can not only stabilize *COOH intermediates but also decrease the energy barrier of intermediates during the CO₂ photoreduction process. In the meantime, forming an S-scheme greatly accelerates the charge transfer between OV-B and SV-C and maintains strong redox capacities for the CO₂ photoreduction reaction. The high selectivity and activity of the dual-defective OV-B/SV-C sample mainly originate from the introduction of oxygen and sulfur vacancies in the CdS/BiOCl and construction of the S-scheme heterostructure. This work paves a promising way for tuning photocatalytic activities and selectivities by constructing a dual-defective S-scheme heterostructure.

中文翻译：

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通过双缺陷 CdS/BiOCl 光催化剂选择性生产 CO2 进行光还原


设计一种新型、高选择性的CO ₂光还原光催化剂具有重要意义，但由于光生载流子复合率高和光催化剂表面反应性弱等问题仍然具有挑战性。在此，通过两步溶剂热法构建了具有氧空位的BiOCl和具有硫空位的CdS（OV-B/SV-C）的双缺陷S型异质结构。所制备的双缺陷复合材料不仅在没有任何空穴牺牲剂的情况下表现出272 μL g ^-1 h ^-1的最大CO析出速率和高CO析出选择性（97%），而且还表现出优异的Cr( VI ）60秒内的光还原性能。实验表征和DFT结果表明，双缺陷引入不仅可以稳定*COOH中间体，而且可以降低CO ₂光还原过程中中间体的能垒。同时，形成S型大大加速了OV-B和SV-C之间的电荷转移，并为CO ₂光还原反应保持强大的氧化还原能力。双缺陷OV-B/SV-C样品的高选择性和活性主要源于CdS/BiOCl中氧和硫空位的引入以及S型异质结构的构建。这项工作为通过构建双缺陷 S 型异质结构来调节光催化活性和选择性铺平了一条有前途的途径。