Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

TiO₂ nanoparticles were synthesized by a sol-gel process using titanium tetra isopropoxide as a precursor at room temperature. Ag-doped TiO₂ nanoparticles were prepared by photoreduction of AgNO₃ on TiO₂ under UV light irradiation and calcinated at 400 °C. Ag-doped TiO₂ nanoparticles were characterized for their structural and morphological properties by Xray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The photocatalytic properties of the TiO₂ and Ag-doped TiO₂ nanoparticles were evaluated according to the degree of photocatalytic degradation of gaseous benzene under UV and visible light irradiation. To estimate the rate of photolysis under UV (λ = 365 nm) and visible (λ ≥ 410 nm) light, the residual concentration of benzene was monitored by gas chromatography (GC). Both undoped/doped nanoparticles showed about 80 % of photolysis of benzene under UV light. However, under visible light irradiation Ag-doped TiO₂ nanoparticles exhibited a photocatalytic reaction toward the photodegradation of benzene more efficient than that of bare TiO₂. The enhanced photocatalytic reaction of Ag-doped TiO₂ nanoparticles is attributed to the decrease in the activation energy and to the existence of Ag in the TiO₂ host lattice, which increases the absorption capacity in the visible region by acting as an electron trapper and promotes charge separation of the photoinduced electrons (e^–) and holes (h⁺). The use of Ag-doped TiO₂ nanoparticles preserved the option of an environmentally benign photocatalytic reaction using visible light; These particles can be applicable to environmental cleaning applications.