Structural, morphological, and optical properties of CuO nanoblade-decorated TiO2 nanotubular photoelectrodes

Abstract

Titania (TiO₂) nanotubular photoelectrodes are a competitive component of titania-based photoelectrochemical water splitting systems. However, TiO₂ actively absorbs light in the UV region, which limits its usefulness in solar water splitting, a fast-growing clean energy alternative. In this study, the structural, morphological and optical properties of CuO/TiO₂ nanostructures on conductive transparent F-doped SnO₂ (FTO) coated glass substrates are engineered for potential application in solar water splitting. The efficacy of a three-step anodization synthesis process to develop free-standing high-fidelity nanotubular TiO₂ thin films $\left(\sim 8\mu m\right)$ is demonstrated. CuO nanoblades were deposited on TiO₂/FTO by a successive ionic layer adsorption reaction (SILAR). An increase in the precursor concentration and number of immersion cycles influenced the adsorption of CuO and the resultant red shift in the absorption range. SEM and TEM analyses confirm the formation of a heterostructure, with evidence of CuO nanostructures within the TiO₂ nanotubular arrays and on the top of the tubes.