In this study, we investigated the development of efficient photocatalysts for environmental remediation under LED visible light. Specifically, we examined two different structures of tungsten trioxide (WO₃) photocatalysts, namely rod and cubic structures, prepared via a hydrothermal method. These photocatalysts were thoroughly characterized using SEM, XRD, and EPR techniques.
The photocatalytic efficiency of these WO₃ structures was evaluated at various LED lamp intensities for the degradation of Rhodamine B (RhB) under visible light (λ > 400 nm). Remarkably, both the WO₃ rod and WO₃ cubic structures exhibited consistent and high-performance levels across different LED intensities, achieving approximately 90% RhB degradation in just 50 minutes. Notably, the WO₃-500 (calcined at 500 ^oC) demonstrated superior performance due to its unique physical properties such as surface area and pore size rather than its crystal structure. The enhanced conversion observed in the WO₃ cubic structure also requires further investigation, possibly related to distinct surface properties.
EPR measurements provided critical insights into the differences in intensity and oxygen vacancy concentrations between calcined and non-calcined WO₃ rods, highlighting the influence of calcination temperature on these properties. The XRD analysis confirmed the high purity and crystallinity of the WO₃ samples.
Overall, this study underscores the importance of defect engineering and material design in achieving effective photocatalysis, with EPR spectroscopy serving as a valuable tool to guide controlled vacancy concentration for enhanced charge trapping and reaction site formation. These findings have significant implications for the development of efficient photocatalysts for environmental applications.

Sara Rahimnejad

Appearances