Kinetics of Aminocarbyne Formation on Pt(111)

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• 作者：Xiaofeng Hu ; Jun Yin ; Randall J. Meyer ; Michael Trenary
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 2, 2015
• 年：2015
• 卷：119
• 期：26
• 页码：14506-14512
• 全文大小：357K
• ISSN：1932-7455

文摘

The kinetics of aminocarbyne (CNH₂) formation from coadsorbed CN and H on Pt(111) was studied in the temperature range of 220 to 235 K by monitoring the time-dependent increase in the 未(NH₂) mode of CNH₂ at 1566 cm^鈥? with reflection absorption infrared spectroscopy (RAIRS). The surface was exposed using a directed-gas doser to 0.05 L of HCN, which immediately dissociates in the temperature range studied to deposit CN and H on the surface. A peak observed at 3348 cm^鈥? is assigned to the CNH intermediate. A simple model with rate constants for CNH formation, CNH decomposition, and CNH₂ formation was used to analyze the experimental time-dependent coverages of CNH₂. A modified model in which hydrogen was assumed to diffuse rapidly over the surface to occupy all available sites as the reaction proceeded was also used to obtain the three rate constants. From the temperature dependence of these rate constants and fits to Arrhenius plots, activation energies of 0.26, 0.22, and 0.41 eV for CNH formation, CNH dissociation, and CNH₂ formation, respectively, were obtained.