title: Graphene oxide-CdS composite with high photocatalytic degradation and disinfection activities under visible light irradiation.
abstract: Graphene oxide (GO)-CdS composites were synthesized via a novel two-phase mixing method successfully. CdS nanoparticles were uniformly self-assembled on GO sheets at water/toluene interface. The photocatalytic degradation (photodegradation) and disinfection activities of GO-CdS composites were investigated thoroughly. The results show that GO-CdS composites exhibit higher efficiency in photodegradation of various water pollutants than pure CdS nanoparticles under visible light irradiation. In addition, the interactions between GO sheets and CdS nanoparticles inhibit the photo-corrosion of CdS and leaching of Cd(2+). Only 3.5 wt% Cd(2+) of GO-CdS was leached out after photodegradation, while 38.6 wt% Cd(2+) of CdS was lost into aqueous solution. Furthermore, the disinfection activity of GO-CdS composites was investigated for the first time. Nearly 100% of both Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) were killed within 25 min under visible light irradiation. The excellent performances of GO-CdS composites can be attributed to that (1) effective charge transfer from CdS to GO reduces the recombination rate of photo-generated electron-hole pairs; (2) uniform deposition of CdS on GO sheets eliminates aggregation of CdS nanoparticles; and (3) the strong interactions between GO and CdS enhancing the durability of GO-CdS composites. Finally, the mechanism behind these excellent performances was verified by transient photocurrent measurement and further confirmed by ESR technique as well as employing a radical scavenging species - dimethyl sulfoxide (DMSO).
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Jincheng
authors.initials: J
authors.lastname: Liu
authors.forename: Darren Delai
authors.initials: DD
authors.lastname: Sun
authors.forename: Wunjern
authors.initials: W
authors.lastname: Ng
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism; D002104:Cadmium / Q000737:chemistry; D019187:Cadmium Compounds / Q000737:chemistry*; D002384:Catalysis; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004203:Disinfection; D004583:Electrons; D004926:Escherichia coli / Q000378:metabolism; D006108:Graphite / Q000737:chemistry*; D017665:Hydroxyl Radical; D008027:Light; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D010777:Photochemistry; D010782:Photolysis; D013440:Sulfides / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D010087:Oxides; D013440:Sulfides; D002104:Cadmium; C034939:cadmium sulfide; D017665:Hydroxyl Radical; D006108:Graphite; D004121:Dimethyl Sulfoxide