Abstract
This paper presents a promising approach to reduce the quantity of Pt required in cathodes for high‐temperature proton exchange membrane (PEM) fuel cells. Based on preliminary experiments, thermally stable Si~0.97~Al~0.03~C and Sn~0.95~In~0.05~P~2~O~7~ were selected as promoter and ionomer, respectively. Si~0.97~Al~0.03~C particles (∼40 nm) and Sn~0.95~In~0.05~P~2~O~7~ particles (∼45 nm) were successfully produced on a carbon support. Pt particles (∼9 nm) were selectively impregnated in the vicinity of the ionomer. Polarisation measurements revealed that the Pt‐Sn~0.95~In~0.05~P~2~O~7~‐Si~0.97~Al~0.03~C/C cathode exhibited much higher oxygen reduction reaction (ORR) activity than that observed for a pure Pt/C cathode, due to the enhanced dissociative oxygen adsorption on the Si~0.97~Al~0.03~C particles and the increased number of reaction sites for the ORR provided by the Sn~0.95~In~0.05~P~2~O~7~ particles. Fuel cell operation tests demonstrated that a Pt‐Sn~0.95~In~0.05~P~2~O~7~‐Si~0.97~Al~0.03~C/C cathode with a low Pt loading of 0.1 mg cm^–2^ provides better cell performance than a Pt/C cathode with a Pt loading of 1.0 mg cm^–2^.