Abstract
In this study, Pt-Ni binary alloy catalysts supported on carbon nanotubes (PtNi/CNTs) were developed to enhance efficiency of oxygen reduction reaction (ORR) for proton exchange membrane fuel cell (PEMFC) application. The CNTs were directly grown on carbon cloths by chemical vapor deposition method and then treated with hydrophilic process. The nickel nanoparticles were deposited on CNTs by pulse electro-planting. Then we attempted three different procedures with four parts, which were: (A) Electro-planting in acid solution, (B) Electro-planting in base solution and (C)(D) Chemical deposition method to deposite Pt particles on the surface of Ni metals. After confirming electrochemical efficiency of PtNi catalysts, the Pt/CNTs specimen was also prepared by the same depositon procedure for comparison. Electrochemical characteristics of the PtNi/CNTs catalyst were investigated via cyclic voltammetry analysis and rotating disk electrode test in 0.1 M perchloric acid. Structure and elementary composition were measured by SEM and ICP-MS analysis. The onset potential of PtNi prepared by chemical deposition procedure (PtNi-C) was higher than others, which indicated that it had lowest activation loss for reduction reaction of oxygen. The single cell tests results shown that the open circuit voltage of PtNi MEA was about 1 V, and the power density of which could reach 849 mW/cm2, which was 70 % and 52 %higher than pure-Pt MEA and commercial MEA. The results indicated that PtNi catalyst had better catalytic activity than pure Pt, and the procedure of directly deposited catalysts on electrode could had better electronic conduction compared with commercial Pt/C MEA.