Self-assembly of a Ag nanoparticle-modified and graphene-wrapped TiO₂nanobelt ternary heterostructure: Surface charge tuning toward efficient photocatalysis

In recent years, tremendous research efforts have been made towards developing graphene (GR)-based nanocomposites for photocatalytic applications. In this work, surface-coarsened TiO₂nanobelts (SC-TNBs) closely enwrapped with monodispersed Ag nanoparticles (NPs) and GR nanosheets (i.e. Ag/GR/SC-TNBs) were fabricated using a facile self-assembly strategy followed by photoreduction. It was found that the as-prepared Ag/GR/SC-TNBs ternary heterostructure exhibited significantly improved photocatalytic performances under irradiation with UV light in comparison with blank SC-TNBs and its binary counterparts owing to the formation of double heterojunctions among the components. The intimate integration of Ag NPs and GR with SC-TNBs achieved by the self-assembly buildup exerts a profound effect on the transfer of photogenerated electrons over the SC-TNBs substrate in which Ag NPs serve as an efficient "electron reservoir" and GR as an electron transporter and collector, thus concurrently prolonging the lifetime of the photogenerated electron-hole pairs and resulting in the remarkably enhanced photoactivity over the Ag/GR/SC-TNBs ternary nanocomposite. In addition, the underlying photocatalytic mechanism was elucidated and the primary active species were determined. This journal is © the Partner Organisations 2014.