Structural and optical study of Cu-doped TiO2 nanoparticles synthesized by co-precipitation method

Abstract

In this study, we synthesized Cu-doped TiO2 nanoparticles using a coprecipitation method, with chemical TiO2 as the base material and CuSO4.5H2O as a dopant precursor. To characterize their compositional, structural, optical, and paramagnetic properties, we employed energy dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, diffuse reflectance UV-Visible spectroscopy, and electron spin resonance (ESR) spectroscopy. The outcome of the research study showed the samples to have a tetragonal anatase structure with grain sizes of 52-54 nm. The secondary CuO phase in the 6 at.% and 12 at.% samples showed a Cu solubility limit in their TiO2 lattice, which also influences the lattice parameters. We observed band-gap narrowing with an increasing concentration of the Cu dopant, as indicated by the redshift on the reflectance band edge. Substituting Ti with Cu atoms led to the detection of a paramagnetic species by ESR spectroscopy.