The adsorption and decomposition of formic acid on Ni(111): The identification of formic anhydride by vibrational spectroscopy
The adsorption and decomposition of formic acid on Ni(111): The identification of formic anhydride by vibrational spectroscopy
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甲酸在Ni(111)上的吸附和分解：振动光谱法鉴定甲酸酐
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
D. Sander
中科院分区：
文献类型：
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作者：
W. Erley;D. Sander
利用热脱附谱（TDS）、电子能量损失谱（EELS）和反射吸收红外光谱（RAIRS）研究了甲酸（HCOOH）在Ni（111）表面上的吸附和分解。在90 K以上的单层覆盖的几个吸附状态进行检测。HCOOH的氢键由强烈红移的OH伸缩模式指示。第一层，可能由吸附的HCOOH二聚体组成，在250 K以上脱水，形成稳定的表面中间体。进一步加热导致已知的表面物质的自催化分解，并产生非常尖锐的CO2和H2的TDS峰。在360 K以上，只有CO留在表面上。在使用DCOOH形成稳定的表面中间体后，通过RAIRS观察到776、1267、1329、2181和2199 cm-1处的模式。后两种模式，这是没有解决的EELS，被解释为对称和反对称CD拉伸模式的表面中间。因此，虽然大多数振动的研究在其他表面上赞成甲酸根离子（HCOO）作为稳定的表面中间体，我们建议在Ni（111）表面上的甲酸酐。在1323和1267 cm−1处观察到的模式被解释为对称和不对称的CO伸缩模式。甲酸酐中间体的存在最终通过使用HCOOH和DCOOH的混合物的实验证实：RAIRS谱表明甲酸在Ni（111）表面上的吸附和分解过程中存在三种不同的中间产物：（HCO）2 O，（DCO）2 O和HCO-O-DCO。电子能量损失光谱（EELS）和反射吸收红外光谱（RAIRS）。在90 K以上的单层覆盖的几个吸附状态进行检测。HCOOH的氢键由强烈红移的OH伸缩模式指示。第一层，可能由吸附的HCOOH二聚体组成，在250 K以上脱水，形成稳定的表面中间体。进一步加热导致已知的表面物质的自催化分解，并产生非常尖锐的CO2和H2的TDS峰。在360 K以上，只有CO留在表面上。在使用DCOOH形成稳定的表面中间体后，通过RAIRS观察到776、1267、1329、2181和2199 cm-1处的模式。后两种模式，这是没有解决的EELS，被解释为对称和反对称CD拉伸模式的表面中间。因此，虽然大多数…
The adsorption and decomposition of formic acid (HCOOH) on a Ni(111) surface has been examined using thermal desorption spectroscopy (TDS), electron energy‐loss spectroscopy (EELS), and reflection–absorption infrared spectroscopy (RAIRS). At 90 K several adsorption states above monolayer coverage are detected. Hydrogen bonding of HCOOH is indicated by strongly red‐shifted OH stretching modes. The first layer, possibly consisting of adsorbed HCOOH dimers, is dehydrated above 250 K and forms a stable surface intermediate. Further heating leads to the known autocatalytic decomposition of the surfaces species and produces extremely sharp TDS peaks of CO2 and H2 . Above 360 K only CO is left on the surface. After forming the stable surface intermediate using DCOOH, modes at 776, 1267, 1329, 2181, and 2199 cm−1 are observed by RAIRS. The latter two modes, which are not resolved by EELS, are interpreted as the symmetric and antisymmetric CD stretching modes of the surface intermediate. Consequently, whereas most vibrational studies on other surfaces favor a formate ion (HCOO) as stable surface intermediate, we propose a formic anhydride on the Ni(111) surface. The modes observed at 1323 and 1267 cm−1 are interpreted as symmetric and asymmetric CO stretching modes. The existence of a formic anhydride intermediate is finally confirmed by an experiment using a mixture of HCOOH and DCOOH: The RAIRS spectra show the presence of all three different kinds of intermediates which are (HCO)2 O, (DCO)2 O, and HCO–O–DCO.The adsorption and decomposition of formic acid (HCOOH) on a Ni(111) surface has been examined using thermal desorption spectroscopy (TDS), electron energy‐loss spectroscopy (EELS), and reflection–absorption infrared spectroscopy (RAIRS). At 90 K several adsorption states above monolayer coverage are detected. Hydrogen bonding of HCOOH is indicated by strongly red‐shifted OH stretching modes. The first layer, possibly consisting of adsorbed HCOOH dimers, is dehydrated above 250 K and forms a stable surface intermediate. Further heating leads to the known autocatalytic decomposition of the surfaces species and produces extremely sharp TDS peaks of CO2 and H2 . Above 360 K only CO is left on the surface. After forming the stable surface intermediate using DCOOH, modes at 776, 1267, 1329, 2181, and 2199 cm−1 are observed by RAIRS. The latter two modes, which are not resolved by EELS, are interpreted as the symmetric and antisymmetric CD stretching modes of the surface intermediate. Consequently, whereas most...