title: Graphene transforms wide band gap ZnS to a visible light photocatalyst. The new role of graphene as a macromolecular photosensitizer.
abstract: We report the assembly of nanosized ZnS particles on the 2D platform of a graphene oxide (GO) sheet by a facile two-step wet chemistry process, during which the reduced graphene oxide (RGO, also called GR) and the intimate interfacial contact between ZnS nanoparticles and the GR sheet are achieved simultaneously. The ZnS-GR nanocomposites exhibit visible light photoactivity toward aerobic selective oxidation of alcohols and epoxidation of alkenes under ambient conditions. In terms of structure-photoactivity correlation analysis, we for the first time propose a new photocatalytic mechanism where the role of GR in the ZnS-GR nanocomposites acts as an organic dye-like macromolecular "photosensitizer" for ZnS instead of an electron reservoir. This novel photocatalytic mechanism is distinctly different from all previous research on GR-semiconductor photocatalysts, for which GR is claimed to behave as an electron reservoir to capture/shuttle the electrons photogenerated from the semiconductor. This new concept of the reaction mechanism in graphene-semiconductor photocatalysts could provide a new train of thought on designing GR-based composite photocatalysts for targeting applications in solar energy conversion, promoting our in-depth thinking on the microscopic charge carrier transfer pathway connected to the interface between the GR and the semiconductor.
authors.affiliation: State Key Laboratory Breeding Base of Photocatalysis, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350002, People's Republic of China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Zhang
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.forename: Zi-Rong
authors.initials: ZR
authors.lastname: Tang
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Xu
mesh_terms: D002384:Catalysis; D006108:Graphite / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000528:radiation effects; D018036:Selenium Compounds / Q000737:chemistry* / Q000528:radiation effects; D017967:Zinc Compounds / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D017319:Photosensitizing Agents; D018036:Selenium Compounds; D017967:Zinc Compounds; D006108:Graphite; C044696:zinc selenide