Ligand effect of SnO₂ on a Pt–Ru catalyst and the relationship between bond strength and CO tolerance

Abstract

Pt–Ru/SnO2/C catalysts were prepared by a rapid quenching method.

Effect of an Sb-Doped SnO2 Support on the CO-Tolerance of Pt2Ru3 Nanocatalysts for Residential Fuel Cells

“…0.28 V. This suggests that the use of the Sb-SnO 2 support accelerated the CO ad oxidation reaction on the Pt 2 Ru 3 catalyst, because the particle size and the average alloy composition for both catalysts were identical, as described above. Such an enhancement in the CO ad oxidation activity on the Pt 2 Ru 3 /Sb-SnO 2 accords well with that reported for the increased oxidation rate of CH 3 OH and HCHO on PtRu/Sb-SnO 2 [11], Pt/SnO 2 [7], and Pt 2 Ru 3 /SnO 2 /C [9]. Nevertheless, the mitigation of CO poisoning for the HOR at 0.02 V on the Pt 2 Ru 3 /Sb-SnO 2 electrode shown in Figure 3 is not ascribable to such an increase in the CO ad oxidation activity, because CO ad is not oxidized at potentials less positive than 0.1 V, even for the Pt 2 Ru 3 /Sb-SnO 2 catalyst at 70 • C, as shown in the CO-stripping voltammogram.…”

“…Very recently, with the use of in situ FTIR at room temperature, a blueshift of the CO L band by ca. 5 cm −1 was observed after the addition of SnO 2 particles to Pt-Ru/C [9]. While the shape of the CO L band was nearly unchanged by the addition of SnO 2 in that work [9], the spectral shape for the Pt 2 Ru 3 /Sb-SnO 2 catalyst in the present work was clearly distinct from that for Pt 2 Ru 3 /CB.…”

“…5 cm −1 was observed after the addition of SnO 2 particles to Pt-Ru/C [9]. While the shape of the CO L band was nearly unchanged by the addition of SnO 2 in that work [9], the spectral shape for the Pt 2 Ru 3 /Sb-SnO 2 catalyst in the present work was clearly distinct from that for Pt 2 Ru 3 /CB. To examine the changes more closely, the integrated intensities of all six peaks were plotted as a function of time in Figure 7, together with changes in the MA for the HOR measured simultaneously in the ATR-FTIR cell.…”

“…A ligand effect was proposed for the methanol oxidation reaction at a PtRu-MoO x catalyst [5]: MoO x was found to weaken the CO adsorption on the Pt-Ru surface, resulting in the enhanced oxidation rate of CO ad . On the other hand, the CO poisoning effect on the HOR rate was found to be mitigated by the addition of SnO 2 particles to Pt/C or Pt-Ru/C [8][9][10], although the mechanism is still unclear.…”

Electrocatalysts for PEM Fuel Cells

“…[128,[151][152][153][154][155] It can be expected that a metal oxide facilitates the electro-oxidation of CO, and hence enhances CO-tolerance. [128,[151][152][153][154][155] It can be expected that a metal oxide facilitates the electro-oxidation of CO, and hence enhances CO-tolerance.…”