Interaction of HNCO with Au(111) surfaces

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• 作者：A.P. Farkas ; A. Berkó ; F. Solymosi ; ^{fsolym@chem.u-szeged.hu}
• 关键词：HNCO ; Au(111) surface ; NCO surface species ; NO&#xA0 ; +&#xA0 ; CO reaction ; HREEL spectroscopy
• 刊名：Surface Science
• 出版年：2012
• 期刊代码：104_00396028
• 类别：ch
• 出版时间：August, 2012
• 卷：606
• 期：15-16
• 页码：1345-1349
• 文件大小：636 K

摘要

The surface chemistry of isocyanic acid, HNCO, and its dissociation product, NCO, was studied on clean, O-dosed and Ar ion bombarded Au(111) surfaces. The techniques used are high resolution energy loss spectroscopy (HREELS) and temperature-programmed desorption (TPD). The structure of Ar ion etched surface is explored by scanning tunneling microscopy (STM). HNCO adsorbs molecularly on Au(111) surface at 100 K yielding strong losses at 1390, 2270 and 3230 cm^鈭?#xA0;1. The weakly adsorbed HNCO desorbs in two peaks characterized by T_p = 130 and 145 K. The dissociation of the chemisorbed HNCO occurs at 150 K to give NCO species characterized by a vibration at 2185 cm^鈭?#xA0;1. The dissociation process is facilitated by the presence of preadsorbed O and by defect sites on Au(111) produced by Ar ion bombardment. In the latter case the loss feature of NCO appeared at 2130 cm^鈭?#xA0;1. Isocyanate on Au(111) surface was found to be more stable than on the single crystal surfaces of Pt-group metals. Results are compared with those obtained on supported Au catalysts.