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

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 H 2 O 2 . 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 H 2 O 2 utilization by generating HO , which enhanced the decomposition of MB. It was found that O 2 •− and O 2 •− /HO • were the main radicals in post Mn/RGO and Mn-Co/RGO treatment, respectively. Both O 2 •− and HO • oxidized MB with a faster rate by the former, but its side reaction can hinder effective utilization of H 2 O 2 while the reverse was true for the latter. A 50   mg/L   MB was completely decomposed within 15   min using 10   mg 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.