Efficient photo-degradation of dyes using CuWO4 nanoparticles with electron sacrificial agents: a combination of experimental and theoretical exploration

Abstract

CuWO₄ is a promising photocatalytic material, responding in the visible light range, to enhance the utilization of solar energy. Here, CuWO₄ nanoparticles have been synthesized via a polyol-mediated synthesis method and subsequently characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis Spectrophotometery combined with theoretical density functional theory (DFT) calculations. For the as-prepared CuWO₄ samples, a strong adsorption capacity for the organic pollutant MB rather than photodegradation has been observed. The first-principle calculation with Heyd–Scuseria–Ernzerhof (HSE) screened coulomb hybrid functional results indicate that localization of hybridization of O 2p-orbitals and Cu 3d-orbitals, large electron effective mass and more positive conduction band edge of CuWO₄ lead to low carrier mobility and thus the high recombination of excited carriers. Meanwhile, the optical absorption spectrum of experimental observation is consistent with theoretical calculations of pristine CuWO₄, demonstrating few defects inhibiting light absorption. To avoid the high rate of recombination of the excited carriers, electron sacrificial agents (H₂O₂, Na₂S₂O₈) are utilized to suppress the recombination. The photocatalytic activity is thus largely improved.