Nanoclusters & Catalysis

Charge density
Electronic charge density maps of (a) Ti13; (b) Ti13H20; (c) Ti13H30 clusters. Link to paper

Our understanding of materials properties, starting from atomic and molecular systems to clusters and larger aggregates, has considerably improved in recent years. Unlike bulk metal surfaces, quantum-effects and adsorbate-induced modulation of electronic properties influence the reactivity of small metal clusters, and their properties become non-scalable. Thus, the reactivity of small metal clusters composed of 10-20 atoms cannot be predicted from properties of single atoms or larger aggregates. Quantitative description of the reactivity in this non-scalable regime constitutes one of the most challenging aspects of contemporary research in catalysis, nanoscience, energy storage, and environmental remediation. Our recent studies on reactivity of small early-transition metal clusters have shown that the reactivity is a strong function of the adsorbate concentration. Since most experimental studies of electronic structures and bonding in metal nanoparticles are carried out at ultra-high vacuum, it is very difficult to monitor in real-time, the changes in the electronic structure of nanoparticles as a function of the adsorbate concentration. The extraordinary progress in methods based on density functional theory in recent years has enabled the possibility of investigating the nature of adsorbate-nanoparticle interaction in the presence of several interacting adsorbates. Our work in this field is directed to the elucidation of electronic structures of nanoparticle comprised of Ti, Pt, Ru, Co, etc. and their binary alloys and the interaction of these clusters with varying concentrations of small molecules such as H2 and CO. Since catalysis is a kinetic phenomena, we are specifically interested in characterizing reaction paths and transition states involved in reactions mediated by nanoparticles so that the corresponding rate coefficients can be calculated. Recent publications for our group in this area is given here.

Selected Publications

Boron nitride graphitic surface

Cover article

Figure 1. Cover article on PCCP. Hydrogen adsorption and clustering on boron nitride graphitic surface. Link to paper.



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Ti55

Figure 2. Optimized structure of Ti55 and Ti55H120. Link to paper.



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Ti13

Figure 3. Optimized structures and electronic charge densities of (a) Ti13H18 and (b) Ti13H6



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Nanoframework

Figure 4. Optimized nanoframework structure consisting of (5,0) SWCNT constrained by phenyl spacers. Link to paper.



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