Formic Acid Oxidation on Pt100−xPbx Thin Films Electrodeposited on Au
Formic Acid Oxidation on Pt100−xPbx Thin Films Electrodeposited on Au
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DOI：
10.1149/1.3599913
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发表时间：
2011-08
影响因子：
3.9
通讯作者：
Sun-mi Hwang;J. Bonevich;J. J. Kim-J.;T. Moffat
中科院分区：
文献类型：
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作者：
Sun-mi Hwang;J. Bonevich;J. J. Kim-J.;T. Moffat
研究了在织构Au（111）上生长的电沉积Pt 100 −xPbx薄膜的甲酸氧化电催化。亚稳态fcc Pt 100-xPbx（0 < x atom % < 50）膜相对于相似粗糙度的Pt膜表现出显著增强的甲酸氧化催化。在-0.15 V SCE下，Pt 83 Pb 17和类似粗糙度的Pt膜之间的增强因子明显超过100。近化学计量比的PtPb薄膜的电沉积产生光滑致密的表面，其表现出相对于Pt电极增强的电催化活性。X射线衍射显示P63/mmc金属间相，而TEM表明形成了fcc Pt 100-xPbx晶格，其尺寸几乎与Au（111）和/或Pt 3 Pb晶格匹配。在考虑表面粗糙度后，致密PtPb和粗糙亚稳fcc相的电催化活性在数量级上相似。通过计时电流法和循环伏安法检查耐久性。富铅和PtPb膜基本上脱合金，特别是在较高的电位下。脱合金的结构仍然表现出显着的电催化行为，这可能是相关的铅upd上可用的Pt表面网站。
Electrocatalytic formic acid oxidation is examined on electrodeposited Pt100−xPbx thin films grown on textured Au(111). Metastable fcc Pt100-xPbx (0 < x atom % < 50) films exhibit significantly enhanced catalysis for formic acid oxidation relative to Pt films of similar roughness. At − 0.15 V SCE an enhancement factor in excess of 100 is evident between Pt83Pb17 and Pt films of similar roughness. Electrodeposition of near stoichiometric PtPb thin films yields a smooth compact surface that exhibits enhanced electrocatalytic activity relative to a Pt electrode. X-ray diffraction reveals a P63/mmc intermetallic phase while TEM indicates the formation of fcc Pt100-xPbx lattice with dimensions almost lattice matched to Au(111) and/or Pt3Pb. After considering the surface roughness, the electrocatalytic activity of the compact PtPb and rough metastable fcc phase are similar in magnitude. Durability was examined by chronoamperometry and cyclic voltammetry. The Pb-rich and PtPb films are substantially dealloyed particularly at higher potentials. The dealloyed structure still exhibits significant electrocatalytic behavior that is presumably related to Pb upd on available Pt surface sites.