Document Detail

Atomistic Theory of Ostwald Ripening and Disintegration of Supported Metal Particles Under Reaction Conditions.
MedLine Citation:
PMID:  23272702     Owner:  NLM     Status:  Publisher    
Understanding Ostwald ripening and disintegration of supported metal particles under operating conditions have been of central importance in the study of sintering and dispersion of heterogeneous catalysts for long term industrial implementation. To achieve a quantitative description of these complicated processes, an atomistic and generic theory taking into account of the reaction environment, particle size and morphology, and metal-support interaction is developed. It includes: (1) energetics of supported metal particles, (2) formation of monomers (both the metal adatoms and metal-reactant complexes) on supports, (3) corresponding sintering rate equations and total activation energies, in the presence of reactants at arbitrary temperature and pressure. The thermodynamic criteria for the reactant assisted Ostwald ripening and induced disintegration are formulated, and the influence of reactants on sintering kinetics and redispersion are mapped out. Most energetics and kinetics barriers in the theory can be obtained conveniently by first-principles theory calculations. This allows for the rapid exploration of sintering and disintegration of supported metal particles in huge phase space of structures and compositions under various reaction environments. The theory is applied to TiO$_{2}$(110) supported Rh particles in the presence of carbon monoxide, and reproduces well the broad temperature, pressure, and particle size range over which the sintering and redispersion occurred in such experiments. The result also highlights the importance of the metal-carbonyl complexes as intermediates for Ostwald ripening and disintegration of supported metal catalysts in the presence of CO.
Runhai Ouyang; Jinxun Liu; Wei-Xue Li
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-31
Journal Detail:
Title:  Journal of the American Chemical Society     Volume:  -     ISSN:  1520-5126     ISO Abbreviation:  J. Am. Chem. Soc.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7503056     Medline TA:  J Am Chem Soc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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