Green Strategy to Reduced Nanographene Oxide through Microwave Assisted Transformation of Cellulose

A green strategy for fabrication of biobased reduced nanographene oxide (r-nGO) was developed. Cellulose derived nanographene oxide (nGO) type carbon nanodots were reduced by microwave assisted hydrothermal treatment with superheated water alone or in the presence of caffeic acid (CA), a green reducing agent. The carbon nanodots, r-nGO and r-nGO-CA, obtained through the two different reaction routes without or with the added reducing agent, were characterized by multiple analytical techniques including FTIR, XPS, Raman, XRD, TGA, TEM, AFM, UV–vis, and DLS to confirm and evaluate the efficiency of the reduction reactions. A significant decrease in oxygen content accompanied by increased number of sp2 hybridized functional groups was confirmed in both cases. The synergistic effect of superheated water and reducing agent resulted in the highest C/O ratio and thermal stability, which also supported a more efficient reduction. Interesting optical properties were detected by fluorescence spectroscopy where nGO,...