Interfacial Charge Transfer and Effective Termination of Electron Recombination Process in (ZnO)(1–x)/2(Bi2O3)x(Dy2O3)(1–x)/2 Heterostructured Nanocomposite Material under Visible Light Irradiation

We have synthesized a novel heterostructured composite material-(ZnO) (1- x )/2 (Bi 2 O 3 ) x (Dy 2 O 3 ) (1- x )/2 wherein electron-hole recombination has been successfully inhibited by an interfacial charge-transfer mechanism across a semiconductor interface. As a result of this, the material possessed enhanced photoresponse under visible light irradiations. X-ray diffraction analysis shows the material to be highly nanocrystalline in nature. The band gap energy as calculated from the UV-vis-diffused reflectance spectroscopy spectrum was found to be 2.68 eV. Morphological studies by high-resolution scanning electron microscopy and high-resolution transmission electron microscopy analyses show the presence of distinct microrod-shaped αBi 2 O 3 and spherical ball-like clusters of ZnO and Dy 2 O 3 nanoparticles. X-ray photoelectron spectroscopy and energy-dispersive X-ray analyses confirm the presence of Bi, Zn, Dy, and O in the material. Atomic force microscopy (AFM) analysis revealed the high surface roughness and porosity of the prepared composite. Electron paramagnetic resonance analysis confirmed the in situ generation of  OH • radicals under visible light irradiation. The photocatalytic efficiency of the (ZnO) (1- x )/2 (Bi 2 O 3 ) x (Dy 2 O 3 ) (1- x )/2 composite material was evaluated by the photooxidation of Orange G (OG) dye molecules under visible light irradiation. The catalyst retained its original efficiency even after the 3rd cycle of its reuse thereby validating the economic feasibility of the system. By-product analysis by ESI-MS + analysis proved the complete degradation of the OG molecules from the aqueous solution.