Light driven fabrication of highly dispersed Mn-Co/RGO and the synergistic effect in catalytic degradation of methylene blue

Abstract

This work reports the synthesis of highly dispersed Mn-Co/RGO via a novel light driven approach having attributes of being green, facile and controllable, for the catalytic degradation of methylene blue (MB) in the presence of H2O2. The prepared catalysts were characterized by TEM, EDS, IR, XRD and XPS techniques. A synergy between RGO and Mn-Co species existed where the former helped in adsorption of MB and stabilization and dispersion of Mn and Co on the surface while the latter improved H2O2 utilization by generating HO, which enhanced the decomposition of MB. It was found that O2•− and O2•−/HO• were the main radicals in post Mn/RGO and Mn-Co/RGO treatment, respectively. Both O2•− and HO• oxidized MB with a faster rate by the former, but its side reaction can hinder effective utilization of H2O2 while the reverse was true for the latter. A 50mg/LMB was completely decomposed within 15min using 10mg of Mn-Co/RGO. Thus the synergistic effect of RGO by adsorption MB and Co species avoiding the side reaction led to enhanced rate of MB decomposition.