Size-Specific, Dissociative Activation of Carbon Dioxide by Cobalt Cluster Anions

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• 作者：Akimaro Yanagimachi ; Kiichirou Koyasu ; David Yubero Valdivielso ; Sandy Gewinner ; Wieland Schöllkopf ; André Fielicke ; Tatsuya Tsukuda
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 7, 2016
• 年：2016
• 卷：120
• 期：26
• 页码：14209-14215
• 全文大小：414K
• 年卷期：0
• ISSN：1932-7455

文摘

The reaction of cobalt cluster anions Co_n^– (3 ≤ n ≤ 17) with CO₂ was studied experimentally and theoretically to explore the size-specific activation mode of CO₂ by Co_n^–. Mass spectrometric measurements revealed that the reactivity depends strongly on cluster size: the reactivity emerges abruptly at n = 7, peaks at n = 8–10, and then gradually decreases with increasing n. Infrared multiple photon dissociation spectra of Co_nCO₂^– exhibit a single peak at ∼1870 cm^–1, similarly to the previously reported spectra of Co_nCO^–. Density functional theory calculations for Co₇CO₂^– as an example revealed that the dissociative adsorption of CO₂ into CO and O is energetically more favorable than nondissociative adsorption. The infrared spectra calculated for dissociated isomers Co₇(CO)O^– reproduced the experimental results, whereas those for nondissociated isomers Co₇CO₂^– did not. The photoelectron spectra of Co_nCO₂^– were shifted dramatically toward higher energies relative to those of Co_n^–, suggesting electron transfer from Co_n^– to the CO and O ligands. These results indicate that the CO₂ molecule adsorbs dissociatively on Co_n^–, in sharp contrast to its nondissociative adsorption onto the Co monomer anion.