Visible‐Light‐Induced Dye Degradation over Copper‐Modified Reduced Graphene Oxide

Abstract

Previously, it was found that reduced graphene oxide (RGO) can degrade rhodamine B (RhB) under visible-light irradiation, but with an extraordinarily slow rate. It was also found that modification of RGO with gold nanoparticles can dramatically accelerate the photoreaction rate. Herein, we describe the preparation and photocatalytic properties of copper-ion-modified RGO composite materials, which display a faster photocatalytic reaction rate and better mineralization under visible-light irradiation than gold-modified RGO. The copper-ion-modified RGO composites were prepared by an immersion method. The characterization results of X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy show the presence of crystalline copper species Cu(2)(OH)(3)NO(3) and Cu(2)(OH)(3)Cl on the surface of RGO. Modification of RGO with the copper species greatly enhances the degradation of RhB--after 3 hours of reaction under visible-light irradiation, the total organic carbon is decreased by about 31%. The copper species act as an electron relay, passing the excited electrons from the RGO sheets to adsorbed oxygen, thus leading to continuous generation of reactive oxygen species for the degradation of RhB.

Efficient synthesis of MoS 2 nanoparticles modified TiO 2 nanobelts with enhanced visible-light-driven photocatalytic activity

“…As the CB of TiO 2 is lower than that of MoS 2 , the TiO 2 can be used as a photoelectronic receiver, the photogenerated electrons of the MoS 2 CB will be transferred to the CB of TiO 2 nanobelts [27]. The photogenerated electrons can be trapped by oxygen molecules in the aqueous solution to form singlet oxygen [37]. Simultaneously, the holes moved in the opposite direction from the electrons, photogenerated holes will be captured within the MoS 2 nanoparticles.…”

Fabrication of ZnO/graphene flake-like photocatalyst with enhanced photoreactivity

“…Since the discovery of graphene in 2004, a great deal of work has been done on the synthesis of graphene/semiconductor composite [3,[9][10][11][12][13][14][15][16][17][18]. Graphene owns a unique two-dimensional layer structure of sp 2 -hybridized carbon atoms and exhibits novel electronic property such as zero-bandgap, high transparency, and highly electronic conductivity for storing and transporting electrons due to its one-atom thickness and large theoretical specific surface area [19][20][21].…”

Highly Photoactive, Low Bandgap TiO2 Nanoparticles Wrapped by Graphene

“…In addition, graphene-TiO 2 NPs performed the aqueous solution to form singlet oxygen. [30] The reactive oxygen species generated from graphene-TiO 2 NPs can cause the oxidative decomposition of MB through demethylation process. [24] Furthermore, tightly bound graphene to TiO 2 NPs on graphene-TiO 2 NPs should promote more rapid electron transfer from the excited MB to TiO 2 via graphene nanosheets, not to the ground state of MB, hindering the recombination of excited electrons and thus accelerating visible light-driven photodegradation of MB.…”