Molten salt synthesis of rutile phase Ag/TiO2 nanowires for efficient photoreduction of Cr(VI)

The morphology of TiO₂ structures is a critical parameter in photocatalysis. Fabricating rutile phase TiO₂ in nanostructures forms is a promising method to increase the surface area of the catalyst, thereby accelerating photocatalytic rates. The Molten salt synthesis (MSS) method can be used to enhance the reaction rate of a crystalline solid over an extended period of time. Nonetheless, TiO₂ photocatalytic activity is limited to UV light exposure. Additionally, modification with Ag (silver) nanoparticle is a potential option for enhancing the photocatalytic activity. In this research, rutile phase TiO₂ with nanowires (NW) morphology was prepared by the molten-salt method with addition of Ag into the surface of TiO₂. The Ag/TiO₂ NW was investigated for its photocatalytic performance to reduce hexavalent chromium (Cr(VI)) under visible-light irradiation. According to the result, Ag/TiO₂ NW achieved Cr(VI) photoreduction efficiency of 96.38 % after 150 min of irradiation time with a rate constant (k_app) of 2.21 × 10⁻² min⁻¹. The photodegradation of Cr(VI) followed pseudo-first-order kinetics. The electron-hole photogeneration was hindered with the existence of Ag nanoparticles, which contributed the increased photocatalytic activity from the rutile phase Ag/TiO₂ NW. This research provided an affordable and eco-friendly approach to produce nanomaterial to enhance photocatalytic activity for reduction of heavy metal.