Unsatisfactory charge separation ability and insufficient active sites are the main factors leading to low efficiency for photocatalytic CO conversion and Cr(VI) reduction. Constructing surface defects to accelerate charge separation is an effective strategy for promoting photocatalytic process. Herein, the oxygen vacancies modulated BiOBr nanosheets were constructed by NaBH solution treatment. Density functional theory calculation results found that the formed oxygen vacancies would increase the electron density around Bi atoms near the oxygen vacancies, and inhibiting recombination of the photoinduced carriers. Besides, abundant oxygen vacancies can effectively enhance the adsorption of CO molecules. Therefore, the BiOBr with rich oxygen vacancies (BiOBr-ROV) shows higher evolution rates for CO (15.66 μmol g) and CH (0.22 μmol g) under irradiation of 300 W Xe lamp for 4 h compared with pristine BiOBr nanosheets (BiOBr) and BiOBr with deficient oxygen vacancies (BiOBr-DOV). The intermediate products in the CO reduction process have been detected by Fourier-transform infrared spectroscopy. Besides, the photodegradation activity of Cr(VI) over BiOBr-ROV is 98.65% under 80 min of irradiation, which is higher than that of BiOBr (78.01%) and BiOBr-DOV (53.67%). The work provides a new possibility to construct photocatalysts with high-performance for solar energy conversion.

中文翻译：

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氧空位调节 BiOBr 纳米片可加速 CO2 和 Cr(VI) 光还原

电荷分离能力不理想和活性位点不足是导致光催化CO转化和Cr(VI)还原效率低的主要因素。构建表面缺陷来加速电荷分离是促进光催化过程的有效策略。在此，通过NaBH溶液处理构建了氧空位调制的BiOBr纳米片。密度泛函理论计算结果发现，形成的氧空位会增加氧空位附近Bi原子周围的电子密度，抑制光生载流子的复合。此外，丰富的氧空位可以有效增强CO分子的吸附。因此，与原始BiOBr纳米片（BiOBr）相比，具有丰富氧空位的BiOBr（BiOBr-ROV）在300 W Xe灯照射4小时下表现出更高的CO（15.66 μmol g）和CH（0.22 μmol g）析出率。氧空位不足的 BiOBr (BiOBr-DOV)。 CO还原过程中的中间产物已通过傅里叶变换红外光谱检测。此外，在80 min照射下，BiOBr-ROV对Cr(VI)的光降解活性为98.65%，高于BiOBr（78.01%）和BiOBr-DOV（53.67%）。该工作为构建用于太阳能转换的高性能光催化剂提供了新的可能性。