Platinum-tin electrocatalyst

Lamy C, Rousseau S, Belgsir EM, Coutanceau C, Leger JM. 2004. Recent progress in the direct ethanol fuel cell Development of new platinum-tin electrocatalysts. Electrochim Acta 49 3901-3908. 

Lamy C., S. Rousseau, E. M. Belgsir, C. Coutanceau, J.-M. L6ger, Recent progress in direct ethanol fuel cell development of new platinum-tin electrocatalysts, Electrochim. Acta, 49, 3901 (2004). 

At temperatures below about 125°C, CO adsorption on platinum is very strong. Even few ppms in the H2 stream cause substantial performance losses on the anode. Therefore, the use of platinum alone is not viable for HOR in the presence of CO in low temperature fuel cells. Thus, platinum-ruthenium, platinum-molybdenum and platinum-tin are being used as anode electrocatalysts for hydrogen oxidation in the presence of CO because they tolerate low ppms of CO without excessive polarization losses. Timgsten carbide (WC) also shows high CO-tolerance [38,44]. 

The type of anode catalyst has a strong effect on the severity of CO poisoning, since the catalyst affects the kinetics of CO adsorption (equation (2.12) and equation (2.13)) and CO oxidation (equation (2.18) and equation (2.19)). Based on these mechanisms, many CO-tolerant electrocatalysts have been developed by Pt alloying, such as PtRu (platinum/ruthenium) [24,38], PtSn (platinum/tin) [39-41], and PtMo (platinum/molybdenum) [42-44]. Generally, alloying Pt with a second element can enhance the catalytic activity of the Pt through one or more of the following effects ... 

V), which was characteristic of platinum alloys [17]. The PtSn/C electrocatalyst with a Pt Sn atomic ratio of 50 50 showed an increase in the currents in the double layer (0.4-0.8V) compared to the PtSn/C electrocatalyst with a Pt Sn atomic ratio of 90 10. This could be attributed to the presence of tin oxide species [17], as observed on the X-ray diffractogram. The PtSn/C... 

Vigier et al. [13] used three types of catalysts (platinum, ruthenium, and tin) in a DMFC. The atomic compositions of the catalysts were varied to get the best performance from each of the combinations. Under different voltammetric conditions Pt-Sn, electrocatalysts are the most active combination toward the methanol oxidation and production of CO, compared to Pt and Pt-Ru electrodes [14-16]. 

Most of the electrocatalysts used in H2 technical electrodes for HOR in low temperature fuel eells are noble metals sueh as platinum, ruthenium, and palladium. Some non-noble metals with aeeeptable catalytie aetivity, alloyed or mixed with noble metals, are eobalt, iron, molybdenum, niekel, tin, and tungsten [31]. Some organic materials, like metal phtaloeianines have also been satisfactory for some reaetions [32]. 

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