Incorporation of Cu2O nanocrystals into TiO2 photonic crystal for enhanced UV-visible light driven photocatalysis

A 3D UV-visible light responsive photocatalyst was fabricated by infiltrating Cu2O nanocrystals (NCs) into TiO2 photonic crystal (PC). Morphology characterization presented that Cu2O NCs with average diameter around 10 nm were dispersed uniformly into TiO2 PC. The transmittance spectra showed that Cu2O NCs/TiO2 260, prepared by integrating Cu2O NCs with TiO2 260 which was fabricated from 260 nm polystyrene spheres, exhibited the highest light harvesting. The photoluminescence spectra confirmed the electron/hole pairs recombination of Cu2O NCs/TiO2 260 was efficiently inhibited due to the unique heterojunction structure between TiO2 and Cu2O. In the photocatalytic degradation of Rhodamine B and Bisphenol A under UV-visible light (320 nm < lambda < 780 nm) irradiation, the kinetic constant using Cu2O NCs/TiO2 260 was 3.99 and 8.37-fold larger than that using TiO2 nanoparticle (NP), respectively. The enhanced photocatalysis benefited from the increased light harvesting owing to the excitation of both TiO2 and Cu2O NCs whose optical absorption was intensified by the photonic effect of TiO2 260 and the high quantum efficiency due to the Cu2O/TiO2 heterojunction. The hydroxyl radical, generated from the protonation of superoxide radical which was derived from the reduction of oxygen by photogenerated electrons, was the main oxidant responsible for pollutant degradation. (C) 2015 Elsevier B.V. All rights reserved.