Galvanic exchange-formed ultra-low Pt loading on synthesized unique porous Ag-Pd nanotubes for increased active sites toward oxygen reduction reaction

Development of an inexpensive high performance catalyst with low Pt loading remains a great challenge. Herein galvanic exchange-formed ultra-low Pt loaded porous Ag-Pd binary alloy nanotubes (Pt/Ag-Pd) was prepared as a catalyst toward oxygen reduction reaction (ORR). With highly dispersed active but ultra-low Pt atoms (Pt: about 5.8 wt%) on the porous binary alloy surface, the Pt/Ag-Pd catalyst increases mass activity toward ORR by 1.82 times than commercial Pt/C while possessing excellent operation stability. The performance enhancement is mainly attributed to the unique porous Pt shell/Ag-Pd core tubular structure for increased active sites and facilitated interfacial electron transfer rate by a unique Ag-Pd jointly modified electronic structure. This catalyst holds great promise for practical applications in low temperature fuel cells.