Semiconductor photocatalysis has been regarded as one of the most promising methods for treatment of Cr(VI)-containing wastewater, but the high recombination rate of photogenerated carriers and photocorrosion have limited severely its practical application. The objective of the current study was to employ a layered double hydroxide (LDH) to mitigate these problems by designing and constructing a multiple heterojunction system of g-C₃N₄/LDH/Ag₃PO₄ (CNLDHAP) through a two-step hydrothermal route. The structures, morphologies, chemical states, and optical properties of the products were investigated systematically. The CNLDHAP composite showed superior photocatalytic activity for Cr(VI) reduction than that of the individual components under visible-light irradiation. The composite exhibited high photocatalytic reduction stability after five recycles. The enhanced photocatalytic performance may originate from the very efficient separation of photogenerated carriers of the multiple heterojunction system. Possible photocatalytic mechanisms for the reduction of Cr(VI) over the CNLDHAP composite photocatalyst are proposed.

半导体光催化被认为是处理含Cr（VI）废水的最有前途的方法之一，但是光生载流子的高重组率和光腐蚀严重地限制了其实际应用。本研究的目的是采用层状双氢氧化物（LDH）通过设计和构建gC ₃ N ₄ / LDH / Ag ₃ PO ₄的多异质结体系来缓解这些问题。（CNLDHAP）通过两步热液路线。系统地研究了产品的结构，形态，化学状态和光学性质。在可见光照射下，CNLDHAP复合材料对Cr（VI）的还原表现出比单个组分优异的光催化活性。在五个循环之后，该复合物表现出高的光催化还原稳定性。增强的光催化性能可能源自多异质结系统的光生载流子的非常有效的分离。提出了在CNLDHAP复合光催化剂上还原Cr（VI）的可能的光催化机理。