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

Abstract

Abstract:We prepared monodisperse Pt 2 Ru 3 nanoparticles supported on carbon black and Sb-doped SnO 2 (denoted as Pt 2 Ru 3 /CB and Pt 2 Ru 3 /Sb-SnO 2 ) with identical alloy composition and particle size distribution by the nanocapsule method. The activities for the hydrogen oxidation reaction (HOR) of these anode catalysts were examined in H 2 -saturated 0.1 M HClO 4 solution in both the presence and absence of carbon monoxide by use of a channel flow electrode at 70 • C. It was found that the CO-tolerant HOR mass activity at 0.02 V versus a reversible hydrogen electrode (RHE) on the Pt 2 Ru 3 /Sb-SnO 2 electrode was higher than that at the Pt 2 Ru 3 /CB electrode in 0.1 M HClO 4 solution saturated with 1000 ppm CO (H 2 -balance). The CO tolerance mechanism of these catalysts was investigated by in situ attenuated total reflection Fourier transform infrared reflection-adsorption spectroscopy (ATR-FTIRAS) in 1% CO/H 2 -saturated 0.1 M HClO 4 solution at 60 • C. It was found, for the Pt 2 Ru 3 /Sb-SnO 2 catalyst, that the band intensity of CO linearly adsorbed (CO L ) at step/edge sites was suppressed, together with a blueshift of the CO L peak at terrace sites. On this surface, the HOR active sites were concluded to be more available than those on the CB-supported catalyst surface. The observed changes in the adsorption states of CO can be ascribed to an electronic modification effect by the Sb-SnO 2 support.

In Situ FTIR Analysis of CO-Tolerance of a Pt-Fe Alloy with Stabilized Pt Skin Layers as a Hydrogen Anode Catalyst for Polymer Electrolyte Fuel Cells

“…As has been observed for the CO adsorption process on various catalysts, the changes in the IR spectra in Figure 4 indicate that the bands consists of multiple components, which can be ascribed to CO ad in slightly different configurations or environments, specifically, terraces or step/edge sites [12,13]. [7,[12][13][14]. A small band around 1950 cm −1 on c-Pt2Ru3/C (see Figure 5) was assigned to COad in a bridged configuration on Pt-Ru and/or Ru-Ru sites [CO-Ru, COB(Pt-Ru) or COB(Ru-Ru)] [13].…”

“…The difference in the CO-tolerance will be discussed in more detail below. By the use of an in situ FTIR cell with the attenuated total reflection configuration (ATR-FTIR) [7,12], the IR spectra on both catalysts at 0.02 V (practical operating potential in PEFCs) versus an RHE and 60 • C by bubbling 1% CO (H 2 -balance) continuously in 0.1 M HClO 4 solution were measured together with the HOR current. The electrolyte solution was first saturated with pure H 2 to measure the initial HOR current and the reference IR spectrum at 0.02 V, followed by changing the gas to 1% CO/H 2 .…”

“…The difference in the CO-tolerance will be discussed in more detail below. [7,[12][13][14]. A small band around 1950 cm −1 on c-Pt 2 Ru 3 /C (see Figure 5) was assigned to CO ad in a bridged configuration on Pt-Ru and/or Ru-Ru sites [CO-Ru, CO B (Pt-Ru) or CO B (Ru-Ru)] [13].…”

Research and Development of Highly Active and Durable Electrocatalysts Based on Multilateral Analyses of Fuel Cell Reactions

“…5,18,24 The CO ad oxidation rate is enhanced further by elevating the temperature or employing an oxide support (e.g., 0.21 V on Pt 2 Ru 3 /Sb-SnO 2 at 70°C). 21 On the other hand, we found that Pt skin/Pt-M alloys (M = Fe, Co, Ni, etc.) exhibited moderate CO-tolerant HOR activities at temperatures7 0°C.…”

“…[1][2][3][4] For PEFC anode and cathode catalysts, the activity and its degradation have been analyzed by multilateral techniques such as X-ray photoelectron spectroscopy combined with an electrochemical cell (EC-XPS), 2,[5][6][7][8] in situ Fourier-transform infrared spectroscopy (FTIR), [9][10][11][12][13][14][15][16][17][18][19][20][21][22] electrochemical quartz crystal microbalance (EQCM), [23][24][25][26] in situ scanning tunneling microscopy (STM), [27][28][29][30][31] in addition to conventional electrochemical measurements such as rotating disk electrode (RDE), [32][33][34] channel flow electrode (CFE), 21,35,36 and channel flow double electrode (CFDE) methods. [37][38][39][40][41][42] Based on these results, new practical catalysts have been synthesized.…”