Promotional roles of Ru and Sn in mesoporous PtRu and PtRuSn catalysts toward ethanol electrooxidation
Promotional roles of Ru and Sn in mesoporous PtRu and PtRuSn catalysts toward ethanol electrooxidation
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DOI：
10.1016/j.ijhydene.2012.12.038
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发表时间：
2013-07
影响因子：
7.2
通讯作者：
Jarupuk Thepkaew;S. Therdthianwong;A. Therdthianwong;A. Kucernak;N. Wongyao
中科院分区：
文献类型：
--
作者：
Jarupuk Thepkaew;S. Therdthianwong;A. Therdthianwong;A. Kucernak;N. Wongyao
研究了Ru和Sn在介孔PtRu和PtRuSn合金中对乙醇电氧化反应的作用。催化剂样品通过在非离子表面活性剂的溶致液晶相的水域中共还原金属前体来制备。从中孔PtRu和PtRuSn催化剂的X射线衍射图获得的微晶尺寸在3.6 nm处大致相同。有一个很好的协议之间的测量晶格参数和计算从修改Vegard定律表明，三元PtRuSn合金已经形成。XPS分析表明，两种催化剂中Ru均以金属形式存在，而PtRuSn中Sn以SnO形式存在。在乙醇溶液中的电化学测量表明，PtRuSn表现出较低的起始电位约0.1 V，也产生了显着较高的氧化电流密度比PtRu。此外，计时电流法测试表明，在0.3 V的低电位（相对于RHE）下，PtRuSn表面上乙醇氧化的中毒率较低。然而，吸附的有毒物质已被有效地从PtRu表面氧化，因此在0.6V的高电位和高温（60 °C）下显示出最耐毒性的催化剂。结果表明，Ru和Sn的添加对乙醇氧化有不同的促进作用. Sn的加入促进了乙醇分子的解离吸附，而Ru的加入则活化了水分子，并使强吸附的CO氧化，Ru和Sn的加入促进了PtRuSn催化剂上乙醇的整体氧化.
The roles of Ru and Sn in mesoporous PtRu and PtRuSn alloys for ethanol electrooxidation reaction were investigated. The catalyst samples were prepared via co-reduction of metal precursors in an aqueous domain of lyotropic liquid crystalline phase of a nonionic surfactant. The crystallite sizes, obtained from x-ray diffractograms of mesoporous PtRu and PtRuSn catalysts, were approximately the same at 3.6 nm. There was a good agreement between the measured lattice parameter and the one calculated from a modification of Vegard's Law suggesting that the ternary PtRuSn alloy had formed. From XPS analysis, the surface species of Ru in both catalysts is in metallic form while Sn in PtRuSn is in SnO phase. The electrochemical measurements in ethanol solution revealed that PtRuSn had exhibited a lower onset potential by about 0.1 V, and also produced a significantly higher oxidation current density than had PtRu. In addition, the chronoamperometry tests demonstrated a lower poisoning rate for ethanol oxidation on the PtRuSn surface at the low potential of 0.3 V vs RHE. However, the adsorbed poisoning species had been effectively oxidized from the surface of PtRu, and consequently shown to be the most poison-tolerant catalyst at a high potential of 0.6 V and a high temperature (60 °C). As a result, Ru and Sn addition exhibited different promotional effects for ethanol oxidation. The addition of Sn promoted dissociative adsorption of ethanol molecules, while the addition of Ru activated the water molecules, which was followed by the oxidation of the strongly adsorbed CO. The added Ru and Sn had enhanced the overall ethanol oxidation on the PtRuSn catalyst.