Adsorption and Reactions of ICH2CN on Cu(100) and O/Cu(100)

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• 作者：Jong-Liang Lin ; Che-Wei Kuo ; Che-Ming Yang ; Yi-Shiue Lin ; Tz-Shiuan Wu ; Pei-Yu Chao
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：October 3, 2013
• 年：2013
• 卷：117
• 期：39
• 页码：19916-19926
• 全文大小：620K
• 年卷期：v.117,no.39(October 3, 2013)
• ISSN：1932-7455

文摘

Monitoring surface species and their bonding structures in link to specific chemical processes has long been an active, important subject in heterogeneous catalysis. In this article, with employment of temperature-programmed reaction/desorption, reflection鈥揳bsorption infrared spectroscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy in combination with density functional theory computation, we present three CH₃CN formation channels from reaction of CH₂CN generated by ICH₂CN dissociative adsorption on Cu(100) and first spectroscopic evidence for CHCN on single crystal surfaces. The CH₃CN formation mechanisms are dependent on CH₂CN adsorption geometries. At lower coverages, CH₂CN is adsorbed with the C鈥揅鈥揘 approximately parallel to the surface. Reaction of these adsorbates produces CH₃CN via first- and second-order kinetics, with the largest desorption rates occurring at 213 K and 400 K, respectively. At or near a saturated first-layer coverage, decomposition of ICH₂CN forms C-bonded CH₂CN (鈭扖H₂CN), which then transforms to N-bonded 鈭扤CCH₂ with tilted orientation. Disproportionation of the 鈭扤CCH₂ generates CH₃CN at 324 K. Thermal products of H₂, HCN and (CN)₂ evolving at higher temperatures are originated from the CHCN dissociation. On oxygen-precovered Cu(100), reaction of CH₂CN forms new surface intermediates of vertical 鈭扤CO and 鈭扖CO, in addition to perturbed CH₃CN desorption. In the conditions studied, formation of H₂, HCN, and (CN)₂ is terminated due to the presence of preadsorbed O. 鈭扤CO and 鈭扖CO on O/Cu dissociate at 525 and 610 K, respectively, into CO and CO₂.