Synthesis, Characterization, and Evaluation of Photocatalytic and Gas Sensing Properties of ZnSb2O6 Pellets

This work reports a low-cost, microwave-assisted wet chemistry synthesis of zinc antimonate (ZnSb2O6) powders with a trirutile structure, yielding highly homogeneous, nanometric particles. X-ray diffraction (XRD) confirmed the formation of the trirutile phase with lattice parameters of a = 4.664 Å and c = 9.263 Å, and an estimated crystallite size of 42 nm. UV–vis spectroscopy revealed a bandgap of 3.35 eV. Scanning electron microscopy (SEM) showed that ethylenediamine, as a chelating agent, formed porous microstructures of microrods and cuboids, ideal for enhanced gas adsorption. Brunauer–Emmett–Teller (BET) analysis revealed a specific surface area of 6 m2/g and a total pore volume of 0.0831 cm3/g, indicating a predominantly mesoporous structure. The gas sensing properties of ZnSb2O6 pellets were evaluated in CO and C3H8 atmospheres at 100, 200, and 300 °C. The material exhibited high sensitivity at 300 °C, where the maximum responses were 5.86 for CO at 300 ppm and 1.04 for C3H8 at 500 ppm. The enhanced sensitivity at elevated temperatures was corroborated by a corresponding decrease in electrical resistivity. Furthermore, the material demonstrated effective photocatalytic activity, achieving up to 60% degradation of methylene blue and 50% of malachite green after 300 min of UV irradiation, with the process following first-order reaction kinetics. These results highlight that ZnSb2O6 synthesized by this method is a promising bifunctional material for gas sensing and photocatalytic applications.