Photoelectrochemical generation of reactive chlorine species (PEC-RCS) is a promising approach for wastewater treatment. However, the inevitable byproduct of harmful oxychloride (such as ClO₃⁻ and ClO₄⁻) severely limits the practical applications of full-spectrum solar-driven PEC-RCS systems. Herein, we investigated three typical photoelectrodes including TiO₂, WO₃ and BiVO₄ for PEC-RCS system and the formation of RCS and toxic oxychlorides. In BiVO₄ photoelectrochemical cell, the concentration of ClO₃⁻ was lower than 0.2 mg/L and the ClO₄⁻ was undetectable within 2 h of reaction. In contrast, the concentrations of ClO₃⁻ were 2.3 mg/L and 2.7 mg/L in the widely used WO₃ and TiO₂ PEC-RCS processes, respectively, which exceeded the health standard of 0.7 mg/L raised by the European Food Safety Authority (EFSA). We proposed that the valence band dependent photoelectrochemical properties of BiVO₄ photoelectrodes could lead to the restricted HO· radical production and the non-HO·-mediated RCS generation, which synergistically inhibited the ClO₃⁻ formation in the RCS activation process.

活性氯物质（PEC-RCS）的光电化学产生是一种有前途的废水处理方法。然而，有害酰氯不可避免的副产物（如CLO ₃ ^-和C10 ₄ ^- ）严重地限制全谱太阳能驱动PEC-RCS系统的实际应用。在这里，我们研究了三种典型的光电电极，包括用于PEC-RCS系统的TiO ₂，WO ₃和BiVO ₄以及RCS和有毒氯氧化物的形成。在BiVO ₄的光电化学电池，CLO的浓度₃ ^-低于0.2毫克/升和CLO ₄ ^-在反应2小时内未检测到。与此相反，CLO的浓度₃ ^-分别为2.3毫克/升，并在广泛使用的WO 2.7 mg / L的₃和TiO ₂ PEC-RCS过程，分别，这超过了欧洲食品凸起的0.7毫克/升的健康标准安全机构（EFSA）。我们提出，BiVO的价带依赖性光电化学性质₄光电极可能导致该受限制的HO·自由基产生和非HO·介导的RCS的生成，其协同地抑制CLO ₃ ^-形成在RCS激活过程。