Cluster Structure and Reactions: Gaining Insights into Catalytic Processes

Abstract

To many researchers outside the field of cluster science it may come as a surprise that much can be learned of its relevance to catalysis, even restricting the discussion to ionized systems. This perspective is largely focused on catalytic oxidation reactions in which oxygen radical centers on transition metal oxides play a dominant role. The objective is to present how fundamental insights into reaction mechanisms can be gained through employing alternative approaches that complement rather than supersede more conventional methods in t he field of catalysis. In view of the well acknowledged role of defect centers in effecting reactivity, and the preponderance of recent papers presenting evidence of the importance of charged sites, the need/desire to conduct repetitive experiments is clear. Presented herein are approaches using clusters to accomplish this in order to unravel fundamental catalytic reaction mechanisms, and to use identified superatoms and the concepts of element mimics to tailor catalysts with desired functionality.

Structural Isomers of Ti2O4 and Zr2O4 Anions Identified by Slow Photoelectron Velocity-Map Imaging Spectroscopy

“…However, its intermode anharmonicity is small; that is, peak D is offset from the origin exactly as the combination of peaks B and C. We assume that the intramode anharmonicity is similarly small, and we give the fundamental frequency as half that of 2ν 8 .…”

Adsorption and dehydrogenation of ammonia on vanadium and niobium nitride cluster cations

“…Gas-phase metal atoms, clusters, and their compounds are considered to be good models for the reactive sites in heterogeneous catalysts [7][8][9][10][11][12][13][14][15][16][17], and particularly the reactions of transition metal nitride clusters [15][16][17] have attracted increasing interest in recent years because of their specific reactivity. The studies of adsorption and reactions of ammonia on metal nitride clusters are therefore useful to understand the nature of the ammonia synthesis and decomposition on metal nitride catalysts.…”

Stable Stoichiometry of Gas-Phase Manganese Oxide Cluster Ions Revealed by Temperature-Programmed Desorption

“…In addition to conventional surface science studies, gas-phase or well-defined deposited clusters have been used as an ideal model to study in detail the relationship between structure and reactivity. 1,2 The mechanism of oxidation of CO and small organic molecules has been explored by reactivity measurements of transition metal oxide clusters containing radical oxygen centers,…”