Mechanistic insights into defect chemistry and tailored photoluminescence and photocatalytic properties of aliovalent cation substituted Zn0.94M0.06-xLixO (M: Fe3+, Al3+, Cr3+) nanoparticles.

In this work, we demonstrate the microwave assisted solution combustion synthesis of aliovalent cations substituted Zn0.94M0.06-xLixO (M: Fe3+, Al3+, Cr3+) nanoparticles. The structural features, photoluminscent and photocatalytic properties were characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), UV-Visible and photoluminescence (PL) techniques. We have introduced the aliovalent cations such as, reducible Fe3+, stable Al3+ and oxidisable Cr3+ ions in to ZnO and investigated its structural and optical properties. The charge balance and defects stoichiometric composition of ZnO, was also studied by co-doping with Li+ ions. By understanding the photoluminscent and photocatalytic activity of doped and co-doped ZnO nanoparticles, the defect chemistry of ZnO is exposed in detail. The photocatalytic efficiency of various doped and co-doped ZnO catalyst was compared with respect to degradation of Rhodamine B dye. Among them, the CZO, AZO and L3AZO catalysts showed enhanced photo-degradation efficiency of 98.1%, 97.6% and 96.6% respectively, which are high as compared to that of ZnO (89%). This work presents a novel and straightforward, low-cost, tunable and scalable fabrication protocol for highly efficient ZnO-based photocatalysts for practical applications.