Microwave-Assisted Synthesis of Cobalt Oxide/Reduced Graphene Oxide (Co<sub>3</sub>O<sub>4</sub>–rGo) Composite and its Sulfite Enhanced Photocatalytic Degradation of Organic Dyes
Owolabi M. Bankole, Segun E. Olaseni, Moses Adeyemo, Adeniyi S. Ogunlaja
Abstract
Abstract One-pot synthesis of Co 3 O 4 nanocrystals on reduced graphene oxide (rGO) was carried out by reacting cobalt nitrate, L-arginine, extract of Laportae aestuans as oxidant, fuel and reducing agent, respectively, in a domestic microwave. Morphologies of Co 3 O 4 –rGo (RGCO) composite was elucidated using UV-Vis, FT-IR, TEM, SEM, EDX, XRD and photoluminescence spectroscopies. The synthesized RGCO composite was applied as heterogeneous photocatalyst in the activation of Na 2 SO 3 (sulfite) as sacrificial agent to degrade cationic dyes: rhodamine B (RhB) and methylene blue (MB), under visible light, at neutral pH 7.0. Photocatalytic performance of as-prepared RGCO was significantly enhanced in the presence of Na 2 SO 3 . Enhanced photocatalytic activity of RGCO was attributed to the synergistic effects between sulfite radicals generated in situ , and reduced graphene oxide, in which rGO served as electron sink to suppress recombination of photogenerated charge carriers. Plausible mechanistic pathways responsible for the activation of sulfite anions in situ are presented in this paper.