Hess Lecture

Professor Enrique Iglesia

Department of Chemical Engineering

University of California, Berkeley

 “Nanostructures and Nanospaces in Catalysis”

The surface reactivity of metal and oxide domains changes markedly as their local structure and electronic properties vary with size and small domains provide active sites 

unavailable on surfaces of larger structures with similar composition.  Turnover rates for oxidation and acid catalysis depend on the ability of oxide nanostructures to stabilize 

anionic species at the relevant transition states, which reflects, in turn, their electronic structure, determined by the size and composition of these domains.  The size and shape

 of metal clusters determine the coordinative unsaturation of atoms at reactive surfaces.  Atoms with low coordination, prevalent on small clusters, lead to stable transition states 

and to more reactive surfaces in the cleavage of chemical bonds in activation of alkanes.  Such atoms can also stabilize reactants, such as chemisorbed oxygen atoms, and make 

them less reactive when such species are used to abstract hydrogen atoms in kinetically-relevant C-H activation steps.  Voids and pockets of molecular dimensions can contain 

and protect active structures and select the reactants that access them and the products that form.  Specifically, they prevent coalescence of small clusters and contact of active 

sites with toxic impurities, while allowing preferential conversion of smaller reactants and stabilization of specific transition states.  These confinement effects confer enzyme-like 

specificity in acid catalysis via partial confinement and selective stabilization of specific transition states. 

Sponsored by the Bernard Andes Hess Family

Thursday, April 2, 11:00 am in ChE 005

Refreshments will be served at 10:45 am in ChE Lobby