(564d) Surface Nanostructure, Diffusion and Catalysis: The Role of Confinement and Surface Chemistry

Chemical reactions are often carried out in nano-structured materials, which can enhance reactions due to interactions with the reacting mixture, high surface area and confinement effects. A systematic study of reactions in confinement is presented, using ab initio and semi-classical methods [1]. We first consider the influence of steric hindrance on the equilibrium and kinetics for the rotational isomerizations of small hydrocarbons, and show that confinement can lead to reaction rates that vary doubly exponentially with pore width [2]. We further consider several reactions to produce hydrogen, including the decomposition of methane and water on carbon surfaces, with and without the presence of defects and added transition metal atoms. These results provide examples of the influence on reaction mechanism, yield and rate of electrostatic interactions with the supporting material, surface defects and surface curvature.

[1] Erik E. Santiso, Milen K. Kostov, Aaron M. George, Marco Buongiorno Nardelli, Keith E. Gubbins, ?Confinement Effects on Chemical Reactions ? Towards an Integrated Rational Catalyst Design?, Applied Surface Science, 253, 5570 (2007).

[2] E.E. Santiso, M. Buongiorno Nardelli and K.E. Gubbins, ?A Remarkable Shape-Catalytic Effect of Confinement on the Rotational Isomerization of Small Hydrocarbons?, Journal of Chemical Physics, 128, 034704 (2008).