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The development of adequate cathode materials is one of the principal tasks for the fabrication of efficient proton-exchange membrane fuel cells (PEMFCs), which are envisaged as clean energy sources for future transport and portable electrodomestic applications. Here, we present a platinum nanoparticle (NPs)-decorated one-dimensional (1D) titanium dioxide nanorod (PtNPs/TiO2NRs) nanocomposite with enhanced electrocatalytic performance towards the oxygen reduction reaction (ORR). The TiO2NRs were prepared through a green approach, utilizing seaweed extract that not only acts as a reducing agent but also serves as a soft template for the directional growth of TiO2 nanostructures. PtNPs of about 3.0 nm average size were decorated over pre-synthesized TiO2NRs through the chemical reduction of Pt ions using sodium borohydride. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy analyses confirmed the presence of strong metal-support interactions (SMSI) in the prepared hybrid nanocomposite. The as-prepared PtNPs/TiO2NRs composite nanostructures exhibited significantly enhanced electrocatalytic performance and stability towards the ORR, with specific and mass activities of 0.428 mA cm−2 at 0.55 V and 128 mA mg−1 Pt, respectively. These values are 7.2 and 3.5 fold higher than that of standard Pt/C catalysts (0.059 mA cm−2 and 36 mA mg−1 Pt), respectively. The enhanced catalytic activity and high stability of the composite catalyst are mainly due to the unique 1D morphology of the TiO2 nanostructures, which provides a greater surface area, and the SMSI enhancing electron transfer rate at their functional interface. The green approach utilized to fabricate the Pt/TiO2NRs composite in the present study provides a new, low-cost strategy for the development of metal–oxide hybrid nanostructures of high electrocatalytic activity for fuel cell applications. [ABSTRACT FROM AUTHOR]

Nanocrystals of sodium antimony oxide, NaSb3O7 (pyrochlore structure, a = 1.030 nm), act as an efficient catalyst support for the electrocatalytic oxygen-reduction reaction (ORR) in acidic media. The NaSb3O7 nanocrystals (edge length ∼ 150 nm) were synthesized by hydrothermal decomposition of SbCl5 in aqueous solution of NaOH. The NaSb3O7 nanocrystals were then decorated with Pt nanoparticles by chemical reduction of H2PtCl6 in water to yield an ORR catalyst, Pt/NaSb3O7. The Pt/NaSb3O7 exhibited higher ORR performance than the state-of-the-art Pt/TiO2- or Pt/C catalysts in terms of the +40 mV higher half-wave reduction potential and the retained electrochemical surface area than the Pt/TiO2 after 10 000-times repeated ORR in an acidic electrolyte. Unlike NaSb3O7, Pt-decorated Sb2O5 (Pt/Sb2O5) was much less active than the Pt/TiO2 or Pt/C. The enhanced ORR activity of the Pt/NaSb3O7 may be attributed to the promoted electron hopping between the Sb3+ and Sb5+ ions in mixed-valence Na1+(Sb3+Sb25+)O7, which is inhibited in single-valence Sb25+O5. [ABSTRACT FROM AUTHOR]