Facile synthesis of tungsten trioxide 3D architectures by a simple chemical solution route and photodegradation of Rhodamine B: structural, thermal, optical and impedance studies

Abstract

A facile chemical precipitation method for slab and flower like WO₃ microstructure having three-dimensional (3D) architecture is reported. The as-prepared WO₃ powder specimens were characterized by X-ray diffraction (XRD) combined with Rietveld refinements, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and UV–vis spectroscopy. SEM and XRD results revealed that the hierarchical WO₃ microstructures with uniform flower-like morphology are congregated by number of interleaving nanosheets which have thickness of 150–180 nm and are crystallized in a single monoclinic WO₃ phase. Thermo-gravimetric analysis shows a major weight loss of 8% due to evaporation of adsorbed water. The impedance spectroscopy of compact WO₃ pellets showed that all samples were semiconducting with a minute difference in electrical properties. The photo-catalytic activity of the as-prepared WO₃ samples was evaluated by the degradation of Rhodamine B (RhB) under ultra-violet light irradiation. The results showed that 3D hierarchical architectures exhibits high photo-catalytic efficiency compared with the slab like structure due to their porous hierarchical structures. The optical band gap energy of slab like structure is found to be lowered compared to flower-like WO₃ structures. These tunable optical and transport features allow the development of new materials for potential applications as photo-catalysts, transparent conducting electrodes, electrochromic and sensor devices.