Long-term, stable, and improved oxygen-reduction performance of titania-supported PtPb nanoparticlesElectronic supplementary information (ESI) available: Bright-field TEM images of Pt and PtPb NPs; XPS profile for PtPb/TiO2 in the C 1s region; Cyclic voltammograms of Pt NPs, PtPb NPs, Pt/VC, Pt/TiO2, and PtPb/TiO2 in argon and oxygen saturated 0.1 M H2SO4; ORR performance of Pt/VC (10 wt% and 20 wt%) and PtPb/TiO2 after 500 electric potential pre-treatment; pXRD profile for Pt/VC; Comparison of

• Main Authors: Gunji, Takao, Saravanan, Govindachetty, Tanabe, Toyokazu, Tsuda, Takashi, Miyauchi, Masahiro, Kobayashi, Genki, Abe, Hideki, Matsumoto, Futoshi
• Format: Article
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/c3cy01112g

The long-term, stable, and improved electrocatalytic performance towards the oxygen reduction reaction (ORR) has been achieved by anatase-type titania (TiO 2 )-supported PtPb nanoparticles (NPs). Organometallic precursors, H 2 PtCl 6 ·6H 2 O and Pb(CH 3 COO) 2 were co-reduced using sodium borohydride at ambient temperature to precipitate the PtPb NPs (NiAs-type structure, P 6 3 / mmc , a = 0.4259 nm; c = 0.5267 nm, average particle size: 3 nm) over the TiO 2 support (PtPb/TiO 2 ). PtPb/TiO 2 showed substantial electrocatalytic activity towards ORR both in terms of the onset potential and the mass activity compared to TiO 2 -supported Pt NPs (Pt/TiO 2 ). The onset potential of PtPb/TiO 2 was shifted to a higher electric potential by 180 mV compared to Pt/TiO 2 . Also, PtPb/TiO 2 showed a seven-times higher ORR mass activity than Pt/TiO 2 . Neither the onset potential nor the mass activity of PtPb/TiO 2 was altered after ORR cycles, whereas those of commercially available Vulcan carbon-supported Pt NPs (Pt/VC; Pt loading: 20 wt%) were largely altered. The PtPb NPs were not agglomerated over the TiO 2 support even after repeated cycles under the electric potential condition, as the result of the strong interactions between the PtPb NPs and the TiO 2 support, but the Pt NPs were significantly agglomerated over the TiO 2 - and the Vulcan carbon-supports due to the weak interactions between the Pt NPs and the supports. PtPb/TiO 2 can be a practical cathode material for direct fuel cells in terms of its long-term stability and enhanced catalytic performance. Anatase-type titania-supported intermetallic PtPb nanoparticles synthesized through a wet-chemical route showed a long-term, stable, and improved oxygen reduction reaction performance.