One pot aqueous synthesis of nanoporous Au85Pt15 material with surface bound Pt islands: an efficient methanol tolerant ORR catalystElectronic supplementary information (ESI) available: Materials, characterization, catalyst and MEA preparation, Fig. S1-S9. See DOI: 10.1039/c4nr04712e

For the first time, we are reporting the synthesis of Au 100− x Pt x nanoporous materials in the size range of 7-10 nm through the galvanic replacement of Ag by Pt from Au 100− x Ag 2 x spherical nano-alloys ( x = 20, 15, 10 and 5) in an aqueous medium. The galvanic replacement reaction follows the 'Volmer-Weber' growth mode, resulting in the formation of surface bound platinum islands on a nanoporous gold surface. The high angle annular dark field image and low angle X-ray diffraction studies confirm the presence of nanoporous Au 100− x Pt x NPs. The electrochemical studies using the Au 85 Pt 15 /C catalyst show excellent methanol tolerance behaviour and better performance towards oxygen reduction reaction (ORR) in terms of high mass activity, mass-specific activity and figure of merit (FOM) when compared to HiSPEC Pt/C commercial catalyst. Preliminary studies on a full cell using nanoporous Au 85 Pt 15 /C (loading 1.0 mg cm −2 ) as the cathode material and Pt-Ru/C (loading: 0.5 mg cm −2 ) as the anode material performed better (38 mW cm −2 ) than the HiSPEC Pt/C cathode material (16 mW cm −2 ). Au 85 Pt 15 /C nanoporous material with surface Pt islands synthesized by galvanic replacement reaction (GRR) act as efficient methanol-tolerant ORR catalyst with high figure of merit, mass and specific activities, performing well in full cell studies.