Preparation, characterization and catalytic applications of TiO2 nanotube/ CdSe and CdWO4 nanocomposites

In this study, two distinct nanocomposite structures were synthesized by decorating TiO₂ nanotube arrays with CdWO₄ nanorods and CdSe coatings (TCW and TCS). The TCW composite was prepared via hydrothermal method and characterized using XRD, XPS, SEM-EDX, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), EIS, and photocurrent measurements to evaluate its structural, morphological, optical, and electrochemical properties. Photocatalytic and photoelectrocatalytic degradation tests of Rhodamine B were conducted under UV and visible light; 95% degradation was achieved under visible light and 99% under UV light. In the presence of chloride ions, complete mineralization of 5 mg/L Rhodamine B occurred within 17 minutes. TCS composites were synthesis with varying CdSe coating durations and characterized by XRD, SEM-EDX, and UV–Vis DRS analyses. Electrochemical CO₂ reduction performance was evaluated via cyclic voltammetry; increasing the coating time enhanced current response and redox activity, with the sample coated for 40 seconds showing the highest catalytic efficiency. Gas products formed during CO₂ reduction were prepared for GC-MS analysis. The results showed that both composites are promising candidates for catalytic applications in environmental conversion processes.