Highly active and stable Pt-(NbO)x/MWCNT catalysts for oxygen reduction reaction in PEMFC

High electro-active and stable electrocatalysts for oxygen reduction reaction (ORR) were synthesized by depositing platinum (Pt) nanoparticles over niobium oxide nanoparticles (NbO) with various Pt:NbO ratios, supported on multi-wall carbon nanotube (MWCNT). Referring to ORR activity, Pt/(NbO)x/MWCNT have higher Pt mass electroactivity than commercial Pt/C electrocatalyst. The high activity of Pt/(NbO)x/MWCNT can be attributed to the reduced OH species adsorption through lateral repulsion between Pt-OH and NbO. The electrocatalytic stability of Pt/(NbO)x/MWCNT was investigated through accelerated potential cycling test (APCT) up to 5000 cycles in potential range of 0.06 V-1.26 V vs RHE which exhibit improved stability against Pt dissolution and Ostwald ripening. The best Pt/(NbO)x/MWCNT formulation was tested as ORR catalyst in single cell PEMFC, reaching a power density of 405 mW cm-2 at 0.4 V and 90 °C, with stable performance after 65