Reactivity of Metal Clusters

Size-Dependent Reactivity of Nano-Sized Neutral Manganese Oxide Clusters toward Ethylene

Neutral manganese oxide clusters with the general composition Mn_2 N O_3 N+x (N=2-22; x=-1, 0, 1) with dimensions up to a nanosize were prepared by laser ablation and reacted with C₂ H₄ in a fast flow reactor. The size-dependent reactivity of C₂ H₄ adsorption on these clusters was experimentally identified and the adsorption reactivity decreases generally with an increase of the cluster size. Density functional theory calculations were performed to study the geometrical and electronic structures of the Mn_2 N O_3 N (N=1-6) clusters. The calculated results indicated that the coordination number and the charge distribution of the metal centers are responsible for the experimentally observed size-dependent reactivity. The highly charged Mn atoms with low coordination are preferential to adsorb C₂ H₄ . In contrast, the neutral manganese oxide clusters are completely inert toward the saturated hydrocarbon molecule C₂ H₆ . This work provides new perspectives to design related materials in the separation of hydrocarbon molecules.

Hydrogen-Induced Adsorption of Carbon Monoxide on the Gold Dimer Cation: A Joint Experimental and DFT Investigation

It is demonstrated, using tandem mass spectrometry and radio frequency ion trap, that the adsorption of a H atom on the gold dimer cation, Au₂H⁺, prevents its dissociation and allows for adsorption of CO. Reaction kinetics are measured by employing a radio frequency ion trap, where Au₂⁺ and CO interact for a given reaction time. The effect of a hydrogen atom is evaluated by comparing reaction rate constants measured for Au₂⁺ and Au₂H⁺. The theoretical results for the adsorption of CO molecules and their reaction characteristics with Au₂⁺ and Au₂H⁺ are found to agree with the experimental findings. The joint investigations provide insights into hydrogen atom adsorption effects and consequent reaction mechanisms.

Small gold clusters catalyzing the conversion of glycerol to epichlorohydrin

The conversion of glycerol to epichlorohydrin (GTE) is of great interest because the product is widely used in plastics, rubbers and adhesives, and also contributes to the disposal of the reactant glycerol, a major by-product in biodiesel production.

Ménage-à-trois: single-atom catalysis, mass spectrometry, and computational chemistry

Genuine, single-atom catalysis can be realized in the gas phase and probed by mass spectrometry combined with computational chemistry.