Nitrogen-doped carbon quantum dot/graphene hybrid nanocomposite as an efficient catalyst support for the oxygen reduction reaction

A nitrogen-doped carbon quantum dot/graphene (N-CQD/G) hybrid nanocomposite was synthesized in-situ using a sacrificial template-assisted pyrolysis method with an oligomeric phenolic resin as the carbon source and dicyandiamide as the sacrificial template precursor/nitrogen source. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, atomic force microscopy, nitrogen adsorption desorption, Raman and X-ray photoelectron spectroscopy were employed to characterize N-CQD/G samples. The Pt nanoparticles were then deposited onto N-CQD/G hybrids (Pt/N-CQD/G) using a polyol reduction method. Structural and morphological investigations for the Pt/N-GQD/G revealed that ultrafine Pt particles with an average size of 2.1 nm, together with CQDs, are uniformly dispersed on the surfaces of graphene nanosheets. Compared with commercial Pt/C catalysts, Pt/N-CQD/G with highly electrochemical active surface area (ca. 123.4 m(2) g(pt)(-1)) show remarkably enhanced electrocatalytic activity and durability toward oxygen reduction reaction (ORR). The superior ORR catalytic performance of Pt/N-CQD/G can be attributed to highly distributed Pt nanoparticles with small size, nitrogen-doping, and strong interaction between metal and support, as well as the unique structure of N-CQD/G hybrids which combines the advantages of both carbon quantum dot and graphene, such as abundant edges and doping sites, high surface area, large pore size and high electrical conductivity. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.