title: Understanding the adsorptive and photoactivity properties of Ag-graphene oxide nanocomposites.
abstract: Nanocomposites of graphene oxide (GO) and silver nanoparticles (AgNPs) were synthetized using a practical photochemical silver functionalization. Their photocatalytic activities were evaluated with two dyes, Rhodamine B and Indigo Carmine, under visible-light irradiation. The prepared nanocomposites were characterized by HRTEM, FESEM, XRD, Raman, FTIR and UV-vis absorption spectroscopy. These nanocomposites present new defect domains of sp(3) type in combination with several graphitic functional groups that act as nucleation sites for anchoring AgNPs, while the sp(2)-sp(3) edge defects domains of GO generate the photoactivity. Furthermore, their photocatalytic performances are governed by their large adsorption capacity, and strong interaction with dye chromophores. A comprehensive photocatalytic way underlying the importance of adsorption is suggested to explain the low visible-light responsive photoactivity of the AgNPs-GO nanocomposites and the possible binding-site saturation. Then, the usage of H2SO4 allows the production of ionic species and helps to confirm the strong adsorption of both dyes. The ability to synthesize AgNPs-GO nanocomposites with extensive adsorptive capacity is certainly of interest for the efficient removal of hazardous materials.
authors.affiliation: División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Col. Lomas 4a. sección, C.P. 78216 San Luis Potosí, S.L.P., Mexico.
authors.forename: R D
authors.initials: RD
authors.lastname: Martínez-Orozco
authors.forename: H C
authors.initials: HC
authors.lastname: Rosu
authors.forename: Soo-Wohn
authors.initials: SW
authors.lastname: Lee
authors.forename: V
authors.initials: V
authors.lastname: Rodríguez-González
mesh_terms: D000327:Adsorption; D004396:Coloring Agents / Q000737:chemistry; D006108:Graphite / Q000737:chemistry / Q000528:radiation effects*; D007203:Indigo Carmine / Q000737:chemistry*; D008027:Light; D064347:Microscopy, Electrochemical, Scanning; D053761:Nanocomposites / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry / Q000528:radiation effects*; D010782:Photolysis; D012235:Rhodamines / Q000737:chemistry*; D012834:Silver / Q000737:chemistry / Q000528:radiation effects*; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D004396:Coloring Agents; D010087:Oxides; D012235:Rhodamines; D013464:Sulfuric Acids; D012834:Silver; D006108:Graphite; D007203:Indigo Carmine; C029773:rhodamine B; C033158:sulfuric acid
keywords: Graphene adsorption capacity; Graphene oxide sp(3) defects; Graphene-based nanocomposites; RhB binding-site saturation; Silver nanoparticles; Strong adsorption