Synergetic effect of heterojunction and doping of silver on ZnNb2O6 for superior visible-light photocatalytic activity and recyclability

This work reports the synthesis of Ag/ZnNb₂O₆ heterojunctions by solid-state approach followed with the photoreduction of silver. It was found that Ag decorated ZnNb₂O₆ catalyst was provided with dual roles of silver, including homogeneous doping of Ag ions into ZnNb₂O₆ host lattice and a large amount of heterojunctions due to the monodispersion of tiny Ag nanoparticles deposited on ZnNb₂O₆ surface, thereby showing the abnormal visible-light absorption ascribed to the interband introduction and the strong surface plasmon resonance. The photocatalytic effects of silver doping and heterojunctions in visible-light irradiation were investigated, which showed Ag(6 wt.%)/ZnNb₂O₆ catalyst had the optimal photocatalytic efficiency (96.5-98.2% within 2 h) for the photodegradation of five various dyes and high recyclability during the photocatalytic degradation of methyl orange.