Effect of reaction time on the phase transformation and photocatalytic activity under solar irradiation of tungsten oxide nanocuboids prepared via facile hydrothermal method

Starch-assisted synthesis of WO3 nanoparticles for degradation of crystal violet dye

“…These superoxide anions serve as an additional source of hydroxyl radical synthesis. ROS support the mineralisation of dyes in the following ways [56]. WO (12) Through these procedures, the catalyst provides the ROS (°OH, °O2 -) mandatory for degradation.…”

Temperature-mediated Phase Transformation and Optical Properties of Tungsten Oxide Nanostructures Prepared by Facile Hydrothermal Method

“…These results confirmed the phase transformation of samples with the reaction temperature, which is in accord with the XRD result. The transformation from monoclinic WO 3 • 2H 2 O to orthorhombic WO 3 •H 2 O, then to monoclinic WO 3 could be explained by the oxolation and dehydration reactions during the hydrothermal process in a highly acidic environment (Scheme 1) [15,[17][18][19][20]. In brief, tungstic acid (H 2 WO 4 ) was initially formed via Eq.…”

“…Note that, the oxolation process occurring on the equator plane results in crystal growth through the preferential shape of the plate with a preferential growth direction (010) in monoclinic WO 3 • 2H 2 O and orthorhombic WO 3 •H 2 O. While during the dehydration process, in the homogeneous [H + ] ion platform, the electric force tends to support the growth equally in the [200], [020], and [002] directions and results in the nanocuboid morphology [20,38]. In sample T150, the phase transformed from orthorhombic WO 3 •H 2 O to monoclinic WO 3 , so both nanoplate and nanocuboid appeared in the sample.…”

“…In the facile hydrothermal treatment -one-step and free of additives, several processing parameters that could be used as controlling parameters such as the acidity [9,18,19], reaction time [18,20,21], reaction temperature [18,[22][23][24]. By varying these parameters, researchers could manipulate the crystal structure and morphology of the products, which then affected the potential for applications.…”

“…Liu and co-workers [23] prepared WO 3 1-D nanorods by hydrothermal method at different temperatures and reaction times, but no phase transformation was reported. In our previous work, we studied the effect of reaction time on the phase transformation of tungsten oxide prepared by a facile hydrothermal route in a highly acidic environment, but only at 180˚C [20]. Based on the above results and a literature survey, there is still a lack of a systematic study about the effect of reaction temperature on the phase transformation of WO 3 prepared via a facile hydrothermal route, especially in a highly acidic environment.…”