Abstract
Titanium dioxide (TiO(2)) is a safe inorganic sunscreen that provides broad-spectrum ultraviolet (UV) protection. It is usually mixed with organic materials or directly applied to the protected area. However, the photocatalytic activity of TiO(2) can decompose organic substances upon UV light exposure, causing negative effects. To further extend the UV protection wavelength range of TiO(2) and reduce its photocatalytic activity, copper/iron sulfate was added to titanium tetraisopropoxide (as TiO(2) precursor) in isopropanol in the presence of hydrochloric acid (as catalyst), yielding Cu(2+)/Fe(3+)-doped TiO(2) nanoparticles. X-ray diffraction analysis revealed the anatase crystal phase in doped TiO(2) nanoparticles annealed at 100 and 400 °C, whereas annealing at 700 °C resulted in rutile phase formation. Doped TiO(2) nanoparticles annealed at 100 °C exhibited an average particle size of approximately 10 nm, and the particle size distribution remained below 100 nm even when annealed at 700 °C, suggesting that Cu(2+)/Fe(3+) inhibited the condensation and crystallization of TiO(2). UV-Visible spectrophotometry analysis confirmed that Cu(2+)/Fe(3+) doping effectively reduced UV light transmittance and enhanced visible light blocking, achieving broad-spectrum light protection. Moreover, by adjusting the weight percentage of Cu(2+) or Fe(3+), doped TiO(2) nanoparticles annealed at 100 °C, 400 °C, or 700 °C demonstrated reduced photocatalytic activity, offering a considerable advantage for sunscreen applications containing organic materials.