Single-step sol-gel synthesis of CuO/TiO2 nanoparticles: Microstructure and materials characterization

Abstract

Copper oxide modified titanium dioxide (CuO/TiO₂) nanoparticles have been widely reported owing to their excellent performance in heterogeneous photocatalysis. However, their industrial and large-scale production is hampered by tedious and expensive preparation methods. The present study presents a single step sol-gel synthesis of CuO/TiO₂ nanoparticles with improved physicochemical properties. A series of CuO/TiO₂ nanoparticles were synthesized by a modified sol-gel approach using titanium oxychloride as a TiO₂ precursor in the absence of additives. The samples were examined by high-resolution TEM, SEM-EDAX, XRD, XRF, XPS, Raman spectroscopy, nitrogen gas physisorption studies, and UV-visible DRS analyses. It was found that the proposed method facilitated the formation of CuO/TiO₂ nanoparticles with superior morphology, crystal structure and optical properties. XRD results showed that the introduction of Cu²⁺ into TiO₂ microstructure delayed the anatase to rutile phase transformation in the calcined samples. Hence, samples with pure anatase phase, pure rutile phase or a mixture of anatase and rutile TiO₂ phases were exquisitely yielded. The band gap energy of the TiO₂ was reduced from 3.14 eV to ~ 2.0 eV due to the presence of CuO. Therefore, the present study provides a convenient method to yielding sol-gel synthesized CuO/TiO₂ with improved physico-chemical properties in the absence of additives.