Photocatalytic degradation of acid red 14 dye by ZnGa2O4 spinel nanoparticles under visible light irradiation

The photocatalysts consisting of p-block metal ions with d10 configuration have different electronic structures from the conventional photocatalysts containing transition metal ions with d0 configuration by the DFT (Density Functional Thoery) calculation [1]. Photocatalysts with the p-block metal ions like Ga3+, In3+, Ge4+, Sn4+ and Sb5+ have shown high photocatalytic activities [2]. ZnGa2O4, a binary compound oxide consisting of ZnO and Ga2O3 with an optical bandgap of 4.4 eV, is widely studied as fluorescent material and photocatalyst [3]. In this paper a novel and inexpensive route for the preparation of spinel ZnGa2O4 nanoparticles is proposed. ZnGa2O4 nanoparticles photocatalyst was synthesized via sol–gel method using natural gel and calcination at 600 °C. This method has many advantages such as nontoxic, economic viability, ease to scale up, less time consuming and environmental friendly approach for the synthesis of ZnGa2O4 nanoparticles without using any harmful chemicals. Acid red 14 was used as model dye. The obtained nanoparticles were then identified using different analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and field emission scanning electron microscopy (FESEM). The X-ray powder diffraction (XRD) confirmed the formation of cubic spinel phase ZnGa2O4. The photocatalytic activity of ZnGa2O4 nanoparticles were studied by performing the decomposition of Acid red 14 dye under visible light irradiation. The effects of process parameters like, catalyst dosage, initial dye concentration, and visible light irradiation on dye degradation have been investigated.