Efficient and sustainable metal-free GR/C3N4/CDots ternary heterostructrues for versatile visible-light-driven photoredox applications: Toward synergistic interaction of carbon materials.

A sheet-on-sheet and metal-free graphene/C 3 N 4 /carbon dots (GR/C 3 N 4 /CDots) ternary heterostructure with efficient visible-light photocatalysis for pollutants degradation has been reported. Via a convenient and hydrothermal method, large-sized GR nanosheets can serve as substrate for monodispersed dispersion of C 3 N 4 nanosheets. A subsequent loading of very small amount of CDots (1 wt%, 2–5 nm) onto sheet-on-sheet heterostructure significantly enhance visible-light-driven photoredox performances of catalysts, including oxidation of organics pollutant (RhB, 96.0%) and reduction of heavy metals [Cr(VI), 83.6%]. Excellent catalytic properties of GR/C 3 N 4 /CDots heterostructure can be predominantly ascribed to the intimate interfacial contact among constructing ingredients, increased specific surface area and enhanced light adsorption derived from GR and CDots carbon materials. Particularly, the synergistic sheet-on-sheet interaction between C 3 N 4 and carbon materials (GR and CDots) remarkably accelerate the electrons/holes separation, giving rise to significantly enhanced photoredox performances of GR/C 3 N 4 /CDots in comparison with other counterparts. The synergism effect between organic contaminants and heavy metals also contributed to the efficient performance of GR/C 3 N 4 /CDots, wherein the O 2− and OH were the main active species in the photoredox reactions. This metals-free heterostructure shows favorable photostability in cyclic experiments. We anticipate that our work could provide a classical paradigm for rational design of efficient and visible-light-driven photocatalysts for their sustainable applications in wastewater treatment. [ABSTRACT FROM AUTHOR]