Hits:

Indexed by:会议论文

Date of Publication:2019-01-01

Included Journals:CPCI-S、EI

Volume:504

Issue:1

Key Words:Cyclic voltammetry; Electrodes; Electrolytic reduction; Fits and tolerances; Fuel cells; Graphite; Methanol; Oxygen; Particle size; Rotating disks, Alkaline solutions; Carbon catalysts; Electrocatalytic behavior; Fuel cell application; Graphite particle size; Methanol tolerance; Oxygen reduction reaction; Rotating disk electrodes, Catalyst activity

Abstract:Graphite powders with particle sizes of 40, 100, 400, and 1000 nm were used as cathode catalysts. The influence of graphite particle size on the electrocatalytic behavior towards the oxygen reduction reaction (ORR) was investigated. The catalytic activity and kinetics of the ORR, and methanol tolerance were tested in alkaline solutions with saturated oxygen via cyclic voltammetry (CV), rotating disk electrode (RDE) and ampero metric i-t curve techniques. Experimental results show that the ORR process of the graphite catalyst with a particle size of 40 nm was close to the four-electron pathway at -0.6 V, exhibiting the best ORR activity. This is ascribed to a greater number of edge defects as ORR active sites in the carbon material. The number of sites can be characterized with X-ray diffraction (XRD) and Raman spectroscopy. Additionally, these graphite catalysts have been demonstrated a superior tolerance to methanol than the commercial 20 wt.% Pt/C electrode in alkaline solutions.