The improved durability of SnOx-Pt/C catalyst compared to that of Pt/C arise from the role of SnOx on the surface of Pt. To gain insights into the correlation between SnOx-Pt interface and durability of the SnOx-Pt/C catalyst enhancement, we further conducted XPS analysis of the catalysts-ink film after being oxidized (under 1.0 V for 15 minutes). As shown in Figure , the Pt 4f spectrum of SnOx-Pt/C catalyst reveals larger fraction of metallic state while a higher portion of Pt oxides in Pt/C catalyst (Figure ). This suggests that SnOx-Pt/C catalyst has stronger antioxidant advantages compared to Pt/C catalyst. Considering the difference in composition and morphology between the two catalysts, the electronic interactions between Pt and SnOx would cause differences in antioxidation property. Considering the SnOx-Pt/C catalyst shows good anti-poison ability to CO during ORR (Figure ), we then use CO as a probe molecular to probe the surface structure discrepancy. It shows that the adsorption of CO on SnOx-Pt/C catalyst is much easier than Pt/C catalyst, since the onset potential of CO oxidation on SnOx-Pt/C is 500 mV more negative (Figure and). The CO absorption properties on catalysts were also investigated by DRIFTS measurement (Figure and). The absorption peaks of the linear (on top) and bridge-bonded CO on SnOx-Pt/C catalyst slightly shift to blue with lower intensity compared to that on Pt/C catalyst. This is consistent with previous work showing that the linear adsorption of CO is much stronger than bridge adsorption on Pt surface, and therefore SnOx-Pt/C catalyst have lower bond coverage. This favorable properties of the SnOx-Pt/C catalyst might promise higher durability in the fuel cell performances. The SnOx-Pt/C catalysts were then applied in membrane-electrode-assembly (MEA) to study their PEMFC performance under both H2-O2 and H2-air conditions. For the MEA test, the Pt loadings in catalysts were adjusted to be ~ 0.05 mg/cm 2 with reasonable backpressure (150 kPaabs). Figure and 5c depict the PEMFC polarization curves of SnOx-Pt/C and Pt/C catalysts at H2-O2 conditions. The mass activity (0.21 A mg -1 ) of the SnOx-Pt/C catalyst at 0.9 V (Figure ) is generally consistent with that obtained on RDE in the half-cell test, which is better than that of the commercial Pt/C (0.13 A mg -1 ). The i-V polarization curve (Figure ) of SnOx-Pt/C catalyst shows a 9% loss in power density after square wave ADT measurement (From 0.6 to 1.0 V with 3 s at each voltage for 10,000 cycles). While the power density of Pt/C declines by about 33% (Figure ). Noteworthy, the SnOx-Pt/C catalyst shows only 17% loss in mass activity, while the Pt/C loses ~77% after 10,000 ADT cycles (Figure ). The H2-air PEMFC tests show that the SnOx-Pt/C catalyst demonstrates satisfying stability in both low current density and high current density regions (Figure ). Unfortunately, the Pt/C catalyst suffers quite severe performance loss after ADT measurement (Figure ). More importantly, the potential decay of SnOx-Pt/C catalyst (22 mV) under 0.8 A cm -2 has surpassing the degradation target (<30 mV) by U.S. Department of Energy (Figure , see details in Table ), while the Pt/C catalyst declines 160 mV. The above experimental evidence indicates that the SnOx-Pt/C catalysts could also sureness excellent durability, and the antioxidant capacity of SnOx-Pt/C catalysts to be elucidated.