부산대학교 도서관

Design highly active and stable catalysts for oxygen reduction reaction (ORR) is crucial for development of high-performance proton-exchange membrane fuel cells. Both carbon supporters and Pt based active components are required to be stable under discharging process. Graphitic carbon materials are known to be of good electrochemical stability. However, most of graphitic carbon materials are chemical inert which is unfavorable for high density deposition of Pt nanoparticles. In this work, raw carbon nanotube (rCNT) is chemically activated via oxidation followed by nitrogen doping and cobalt doping. The chemical activation of rCNT provides sufficient active sites for high density Pt nanoparticles deposition while the treatment process unexpectedly reduces sp3 defects of carbon nanotubes. The final composite of Pt densely deposited cobalt/nitrogen co-doped carbon nanotube (Pt/Co-NCNT) shows effectively increased ORR activity and stability than that of Pt/rCNT and commercial Pt/C catalyst. The electron compensation from cobalt and nitrogen to Pt nanoparticles is found, which is favorable for tuning catalysts’ ORR activity. The strong interaction between Pt nanoparticle and Co-NCNT benefits Pt nanoparticles’ size stabilization and depresses the activity decay. The mass activity of Pt/Co-NCNT is found to be 0.36 A·mgPt−1 at 0.9 V vs RHE via measurement on rotation disk electrode (RDE) in compared with 0.11 A·mgPt−1 of commercial Pt(20 wt%)/C catalysts.