Silver-attached reduced graphene oxide nanocomposite as an eco-friendly photocatalyst for organic dye degradation

Dye effluents play a major role in polluting water bodies, and various treatment technologies are being used for their removal. Among these methods, green photocatalysis involving solar radiation has achieved tremendous momentum because of its economically viable and environmentally friendly nature. Noble metals, especially silver, shows visible light catalytic activity and this makes it a suitable candidate for photodegradation of organic dyes. Here, we report the synthesis of silver nanoparticles supported on graphene oxide sheets by a hydrothermal method. We have grown silver nanoparticles on highly conducting reduced graphene oxide sheets, thereby preventing electron-hole pair recombination. The asprepared silver-decorated reduced graphene oxide nanocomposite was characterized by UV-Vis spectroscopy, X-ray diffraction, Raman spectroscopy, photoluminescence technique, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and BET measurements. The photocatalytic ability of the prepared composite was evaluated against two dyes- indigo carmine and methylene blue-in the presence of sodium borohydride as an inducer. The calculated apparent rate constants and the measured TOC values indicate the enhanced catalytic efficiency of the sample as compared to pure silver nanoparticles. A possible pathway and mechanism for photocatalytic dye degradation under solar radiation is also included in this work.