Preadsorption Effect of Carbon Monoxide on Reactivity of Cobalt Cluster Cations toward Hydrogen

Abstract

We report gas-phase reactions of free Co n (CO) m + (n = 3−11, m = 0−2) with H 2 , expecting a catalytic reaction of coadsorbed CO and H 2 on Co n + . Preadsorption of CO molecules is found to promote H 2 adsorption, in particular, on Co n (CO) + (n = 5, 8−10). Density functional theory (DFT) calculations reveal that the reactivity is governed by the molecular-orbital energy of Co n + , which is tuned by preadsorbed CO molecules. Collision-induced-dissociation experiments performed on Co n COH 2 + (n = 8−10) imply that at least some of the CO and H 2 molecules are bound together on Co n + .

Hydrogen Storage Capacity of Cobalt Cluster Ions

“…10 Arakawa et al showed that the preadsorption of CO molecules promoted H 2 adsorption, especially on Co n (CO) + (n = 5, 8−10). 11 Recently, the adsorption processes of multiple hydrogen molecules have been studied, with a focus on the hydrogen storage properties of small particles. Fielicke et al measured the number of H atoms adsorbed on 3d-metal cluster ions as a function of the cluster size and determined the geometrical structures of Co 4 H 2 + , Co 5 H 6 + , and Co 6 H 4 + based on the vibrational structures observed by infrared multiple-photon dissociation spectroscopy.…”

“…Liu and Armentrout measured the kinetic-energy-dependent cross sections for the reactions between Co n + ( n = 2–16) and D 2 , and elucidated the exothermic behavior for the formation of Co n D 2 + ( n = 4,5,10–16) . Arakawa et al showed that the preadsorption of CO molecules promoted H 2 adsorption, especially on Co n (CO) + ( n = 5, 8–10) …”

Reaction of size-selected iron-oxide cluster cations with methane: a model study of rapid methane loss in Mars’ atmosphere

“…11,12 In addition, coadsorption and subsequent reaction of CO and H 2 molecules on cobalt cluster cations, Co n + , have been examined to discuss the formation of organic molecules on the clusters. 13…”

“…11,12 In addition, coadsorption and subsequent reaction of CO and H 2 molecules on cobalt cluster cations, Co n + , have been examined to discuss the formation of organic molecules on the clusters. 13 Another chemical process among recent topics in space is rapid methane loss in the atmosphere of Mars. 14 Observation by the Curiosity rover found temporary spikes of methane and its rapid loss, but the mechanism of the loss has not been elucidated yet.…”

Exploring s–d, s–f, and d–f Electron Interactions in AgnCe+ and AgnSm+ by Chemical Reaction toward O2

“…In this context, we have reported systematic measurements of reactivity of the doped clusters against O 2 ; oxygen etching is frequently employed to examine the stability of the clusters. − When multiple-collision reaction experiments are performed, not only the reactivity but also successive elementary reaction processes can be elucidated. − We have found that the doped anionic clusters, Ag 14 Sc – , Ag 13 Ti – , and Ag 12 V – , as well as cationic clusters, Ag 16 Sc + , Ag 15 Ti + , Ag 14 V + , Ag 11 Fe + , Ag 10 Co + , and Ag 9 Ni + , exhibit a reactivity minimum in the size-dependent measurement of reaction rate coefficients along with reaction kinetics; − the low reactivity suggests that these clusters are stable due to the 18-electron shell closure including delocalized 3d electrons of the dopant atom. In contrast, Ag 9 Fe – , Ag 8 Co – , and Ag 7 Ni – , possessing an exohedral dopant geometry, were highly reactive even with 18 valence electrons, which suggests that an endohedral geometry plays a key role in 3d delocalization …”