Innovation Platform of Intelligent and Energy-Saving Textiles, School of Textile Science and Engineering, Tiangong University, Tianjin 300387, PR China; State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tiangong University, Tianjin 300387, PR China.
Innovation Platform of Intelligent and Energy-Saving Textiles, School of Textile Science and Engineering, Tiangong University, Tianjin 300387, PR China.
J Colloid Interface Sci. 2022 Sep 15;622:50-61. doi: 10.1016/j.jcis.2022.04.109. Epub 2022 Apr 25.
Photocatalytic reduction of Cr(VI) in water environments attracts more attention; however, the mechanisms involved in this process have not been clearly elucidated yet. In this study, the photocatalytic reduction of Cr(VI) by polydopamine modified BiWO (PDA/BWO) under visible light was conducted. Kinetics results show that PDA apparently accelerates the reduction of Cr(VI). The quasi-first-order kinetic constant of Cr(VI) reduction by 5PDA/BWO is 70.0 times that of the original BWO, reaching 0.070 min. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman analyses confirm the formation of ligand-to-metal charge transfer (LMCT) complex [Bi(III)OC] between PDA and BWO. The formed Bi(III)OC complex enhances visible light response and narrows the bandgap of PDA/BWO. The photoelectrochemical and photoluminescent characterization further reveals that the formed Bi(III)OC complex inhibits the recombination of carriers, thus enhancing the photocatalytic reactivity of PDA/BWO. Electrons, are derived from three paths, including dye sensitization, LMCT and bandgap excitation, contribute to Cr(VI) reduction by PDA/BWO. This study provides new insights on the paths of Cr(VI) reduction by PDA/BWO under visible light.
水环境中 Cr(VI)的光催化还原受到了更多的关注；然而，该过程涉及的机制尚未得到明确阐述。本研究采用聚多巴胺修饰的 BiWO（PDA/BWO）在可见光下催化还原 Cr(VI)。动力学结果表明，PDA 明显加速了 Cr(VI)的还原。5PDA/BWO 还原 Cr(VI)的准一级动力学常数是原始 BWO 的 70.0 倍，达到 0.070 min。X 射线光电子能谱、傅里叶变换红外光谱和拉曼分析证实了 PDA 和 BWO 之间形成了配体到金属电荷转移（LMCT）配合物 [Bi(III)OC]。形成的 Bi(III)OC 配合物增强了可见光响应并缩小了 PDA/BWO 的带隙。光电化学和光致发光特性进一步表明，形成的 Bi(III)OC 配合物抑制了载流子的复合，从而提高了 PDA/BWO 的光催化活性。电子来自三个途径，包括染料敏化、LMCT 和带隙激发，有助于 PDA/BWO 还原 Cr(VI)。本研究为可见光下 PDA/BWO 还原 Cr(VI)的途径提供了新的见解。
