Eco-Friendly Transition-Metal-Ion-Doped rGO Nanocomposites with Enhanced Photocatalytic Activities

Abstract

Improving the photocatalytic properties of various types of metal oxides is becoming increasingly important in terms of environmental factors. Carbon allotropes are eco-friendly materials, and improving their photocatalytic properties via doping-induced modifications is one of the most attractive research areas. In this context, various first-row transition-metal-ion-doped reduced graphene oxide samples are synthesized and characterized using high-resolution transmission electron microscopy along with X-ray absorption spectroscopy to investigate their morphological and electronic structures at the molecular level. Transition metal-ion doping produces several defect structures at the oxygen functionalities of reduced graphene oxide nanocomposites (rGO). Such defect structures are well correlated with their photocatalytic activity; Cr@rGO and Fe@rGO exhibit decent activities among the four tested rGO samples in the photocatalytic degradation of organic pollutants and selective oxidation of 2,5-hydroxymethylfurfural. To test the environmental factors, cytotoxicity tests are performed by incubating the modified rGO with human skin cells; Fe@rGO is found to be the least toxic. Therefore, Fe@rGO displayed both enhanced photocatalytic activity and environment-friendly character as compared to the bare rGO, indicating that it is a plausible candidate for application in the petrochemical transformation of biomass without environmental concerns.