Enhanced electrocatalytic activity of N-doped nano-onion/gold nanorod nanocomposites for the oxygen reduction reaction

Abstract

The development of improved electrocatalysts for the oxygen reduction reaction (ORR) is a key to achieving green energy conversion and storage. In this study, heterogeneous amorphous nanoonions were derived from nanodiamonds by thermal annealing and subsequently doped with nitrogen by hydrothermal and pyrolytic methods as potential catalytic supports. Electrocatalytic activity and capacity of the nanocomposites with gold nanorods were significantly modulated for the ORR, depending on heteroatom N configuration into the nanoonions. AuNR/ N-doped nanoonion composite having chemical composition of rich pyridinic and low amine N exhibited mainly first-order linear kinetics, indicating four-electron transfer toward the ORR. AuNR/hydrothermally N-doped nanoonions composite having high pyrrolic and lower pyridinic N affected the pseudocapacitance. The interfacial interaction between gold and amorphous nanoonion provided facilitated electronic transfer on the heterojunction and thus, electrocatalytic activity were critically affected by N configuration-dependent nanoonoin for ORR. The N-doped nanoonions reported herein are a potential platform to develop diverse metal composites with electrocatalytic functions by providing excellent conductivity and resistance to gold decomposition.