▎ 摘　　要

The ternary reduced graphene oxide (rGO)/g-C3N4/Ag-AgCl composite photocatalysts were prepared by a combined deposition-precipitation and in situ photoreduction method. The prepared ternary graphene-semiconductor-metal nano-composite photocatalysts exhibit controlled photocatalytic selectivity and high photocatalytic activity for the degradation of methylene blue (MB) and methyl orange (MO) solution under visible-light irradiation. Significantly, the controlled photocatalytic selectivity of rGO/g-C3N4/Ag-AgCl (GCA) composites towards MO and MB can be modulated by the introduction or elimination of Ag-AgCl and/or rGO sheets for tuning their surface charges and adsorption properties. In addition, the photocatalytic activity of GCA sample was indeed improved due to the efficient separation of photo-generated carriers in the GCA composite, which could be attributed to the suitable band gap structure of g-C3N4/Ag-AgCl (CA) and the well electronic mobility of rGO sheets. The proposed mechanism for the controlled visible-light photocatalytic selectivity and the enhanced photocatalytic activity of GCA composite was further confirmed by the trapping experiments, PL spectroscopy and transient photoelectric current response. This work may provide a new practical insight into the fabrication of innovative photocatalysts with the controlled selectivity and enhanced photocatalytic activity for environmental purification, clear energy production and solar energy conversion.