Nano Ag/TiO₂ catalyst prepared by chemical deposition and its photocatalytic activity

A series of Ag/TiO₂ was prepared by chemical deposition method using silver nitrate, cetyltrimethyl ammonium bromide, and sodium borohydride. Silver nanoparticles were synthesized and cetyltrimethyl ammonium bromide was used as the surfactant to disperse Ag particles in water, Ag particles were then deposited on TiO₂. The catalysts were characterized by inductively-coupled plasma-mass spectroscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy. The photocatalytic reaction of these catalysts for methylene blue destruction was carried out in a batch reactor under UV light irradiation. Ag particles were finely dispersed and homogeneously distributed on TiO₂ support and had strong metal support interaction with TiO₂ by using chemical deposition method. Large amount of hydroxyl groups were on the surface of the catalysts. The photocatalytic activity increased after loading with Ag. Ag particles offered electron traps to decrease the recombination of electrons and holes, but too many Ag nanoparticles block the TiO₂ surface from light scattering. The optimum Ag loading was 2wt%.