부산대학교 도서관

Oxygen reduction reaction (ORR) is an essential reaction at cathode in fuel cell. However, this reaction is well recognized as sluggish kinetics causing the most limiting factor in fuel cell efficiency. The catalytic preparation technique named as strong electrostatic adsorption is able to enhance ORR activity with remarkably high Pt dispersion. To further improve ORR activity from this preparation technique, the heat treatment was studied in this work. The various temperatures were examined after reduction step. The physical and electrochemical characterizations were evaluated by X-ray diffraction, Transmission electron microscopy, X-ray photoelectron spectroscopy, Cyclic voltammetry, and Linear sweep voltammetry. The ORR activity was obtained by performing LSV in saturated oxygen, and the specific activity (SA) was estimated accordingly. The maximum SA, 2.5-fold higher than non-heat treatment, was achieved in the sample that was heat treated at 600 °C. This condition likely yielded the most optimal combination of Pt metal particle size, relative activity plane, and electrical conductivity. Aging times between 0.5 and 4.0 h at 600 °C were investigated. The results suggest that the metal particle size, relative activity plane, and degree of crystallinity could possibly be the main factors yielding the highest SA at aging time of 2 h. [ABSTRACT FROM AUTHOR]