A novel CuO-Cu2O/Ag-Ag3PO4 nanocomposite: Synthesis, characterization, and its application for 2-chlorophenol decontamination under visible light

Herein, a facile one-pot coprecipitation strategy was used to prepare CuO--Cu2O/Ag-Ag3PO4 heterojunction nanocomposite as an effective catalyst for 2-chlorophenol (2-CP) degradation under visible light. The novel CuO--Cu2O/Ag-Ag3PO4 nanocomposite was calcined at various temperatures (i.e., 250, 400, and 550 degrees C) to enhance its photocatalytic properties. The physicochemical properties of the as-prepared nanocomposite and the calcined forms were investigated using XRD, TGA, FTIR, XPS, and SEM. The results indicated that the optical properties were greatly affected by calcination temperature up to 400 degrees C, while the calcination temperature of 550 degrees C resulted in melting of CuO--Cu2O/Ag-Ag3PO4 nanocomposite. Compared to the annealed forms at 250 and 550 degrees C, the CuO--Cu2O/Ag-Ag3PO4 treated at 400 degrees C showed the highest decomposition percentage (82.5%) for 2-CP. This maximum value was mainly due to the reduction in band gap energy and the formation of heterojunction between CuO|Cu2O|Ag|Ag3PO4, which enhanced the separation of photogenerated charge carriers. The degradation of 2-CP was investigated under different solution pH values, and the optimum degradation was detected at pH 3.0 within 180 min. The photocatalysis data were also fitted to the zero-order, first-order, and second-order kinetic models. The highest rate of 2-CP degradation (k(1)= 9.3 x 10(-3)1/min) by Cu2O/Ag-Ag3PO4-400 nanocomposite followed the first-order kinetic model. The reusability study revealed that CuO--Cu2O/Ag-Ag3PO4 annealed at 400 degrees C is considered as an effective photocatalyst for the decomposition of 2-CP-bearing solutions. (c) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.