Oxygen reduction reaction activity of nitrogen, oxygen and sulphur containing carbon derived from low-temperature pyrolysis of poultry featherfiber

Abstract

Poultry featherfiber (PFF), the soft fibrous part of poultry feathers, is used as the novel precursor to derive N-, O- and S-doped-carbon (CNx) electrocatalysts. The catalysts are synthesized by a low-temperature pyrolysis of PFF or a mixture of PFF and Fe/Co salts in varying concentrations, followed by acid-treatment to remove the metal from pyrolyzed samples. Electrochemical measurements in alkaline media exhibit significant ORR electrocatalytic activity of CNx with an ORR onset potential of ∼-230mV (vs. Ag/AgCl), which is comparable to Pt (∼-210mV) under similar conditions. Despite the absence of metal-carbon bonds, the CNx electrocatalysts synthesized in presence of Fe/Co exhibit catalytic activity significantly higher than that of the CNx synthesized without metals. This is attributed to the modified chemical states of C-N and C-O sites due to the presence of Fe/Co during pyrolysis. Hence, presence of metal precursors during pyrolysis affects the ORR activity of CNx indirectly. The CNx catalysts synthesized in presence of varying Fe to Co ratio contain varying N-content and the ORR peak current is found to vary linearly with the N-content. Observed ORR activity of the present catalyst makes it a suitable Pt-free catalyst for low temperature fuel cells.