Here, a hybrid material of sandwiched reduced graphene oxides (rGO) and N, S co-doped carbon quantum dots (N, S-CQDs) was prepared following a facile synthetic route. This metal free composite has demonstrated their dual performance as electrode material for supercapacitor and fuel cell catalyst. It shows robust cyclic stability with high energy and power density without any binders. The enhanced activity of the composite can be ascribed to the substantial role of CQDs present within the interlayer of rGO to enhance the accessible for charged ions which depicts the increased capacitance of composites. In addition, the electrocatalytic activity of the composite has been assessed as metal free cathode catalyst towards the oxygen reduction reaction (ORR) for fuel cell applications. It shows better performance in terms of high reduction potential and high reduction current as compared to the rGO. This can be ascribed due to the significant contribution of electron rich heteroatom doped CQDs as well as the synergistic effect of both CQDs and rGO for electrocatalytic reduction of oxygen. The interesting dual performance of heteroatom doped CQDs and graphene hybrid composites hold potential for development of energy storage and conversion devices.
A facile and green approach for the synthesis of highly electroactive branched Pt nanostructures well dispersed on graphene has been developed by in situ reduction of graphene oxides and Pt(iv) ions in an aqueous medium. The as-synthesized branched Pt and graphene hybrid nanomaterials (GR-BPtNs) were thoroughly characterized using Transmission Electron Microscope (TEM), UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Raman spectroscopy. This report clearly exploits the decisive role of the graphene support, the pH of the solution and the stabiliser on shaping the branched morphology of the Pt nanostructures well dispersed on graphene. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy (EIS) measurements were employed to investigate the electrocatalytic performance and durability of GR-BPtNs towards methanol oxidation and oxygen reduction. The results reveal that the synergetic effect of the graphene support and the branched morphology triggers electrocatalytic performance and robust tolerance to surface poisoning of GR-BPtNs.
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