Synthesis of Cu2O nanocrystals/TiO2 photonic crystal composite for efficient p-nitrophenol removal

Abstract Cu 2 O nanocrystals/TiO 2 photonic crystal (Cu 2 O NCs/TiO 2 PC) photocatalyst was prosperously synthesized and applied to the degradation of p -nitrophenol (PNP). The composite were characterized with scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectrometer (ICP-AES), and UV–vis diffuse reflectance spectrum (UV–vis DRS) techniques. The PNP photocatalysis was performed by varying Cu 2 O NCs loading amount, PNP initial concentration, and solution pH value. Under optimal experiment conditions, the kinetic constant of 0.85-Cu 2 O NCs/TiO 2 260 (where 0.85 represents the mass fraction of Cu 2 O in composite, and 260 denotes the PC structure derived from 260 nm polystyrene spheres) was 4.57-fold higher than that using pristine TiO 2 . The improvement was thanks to the enhanced light harvest by integrating Cu 2 O NCs with TiO 2 PC in which the light absorption were efficiently strengthened and the increased quantum yield owing to the p-n junction between TiO 2 and Cu 2 O. The superoxide anions originated from the one electron reduction of oxygen molecules by the conduction band electrons was responsible for PNP removal. According to the identified intermediates, aliphatic alcohols, aldehydes and carboxylic acid, the possible PNP decomposition path was put forward. We believe this research could supply valuable knowledge for PNP decomposition and impel the technical development of photocatalysis.