Short communication: Onion skin waste-derived biocarbon as alternative non-noble metal electrocatalyst towards ORR in alkaline media

摘要

In this work a first approximation to obtain non-noble metal electrocatalysts from onion skin wastes is reported. Biocarbon were obtained at a range of 600-800 degrees C of pyrolysis temperature activated by chemical treatment with HNO3. It was observed that the pyrolysis temperature has a direct effect on the structural and textural properties, besides the morphology of the onion skin waste-derived biocarbon, which shows to have influence on the catalytic activity for the oxygen reduction reaction ORR. AOB700 was the non-noble metal electrocatalyst with the best performance for the ORR evaluated in alkaline electrolyte (0.5 mol L-1 KOH), which had the highest surface area (242 m(2)g(-1)) and a current density of -2.35 mA cm(-2) with an onset potential of 0.82 V/RHE. The chemical surface composition shows that N-pyridinic, N-amine, N-quaternary and N-pyrrolic nitrogen species are present on this electrocatalysts. The use of onion skin waste as raw material in the production of non-noble metal electrocatalysts is a sustainable solution to avoid the disposal of abundant biomass residues as onion skins. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.