Dynamic Chemical and Structural Changes of Heterogeneous Catalysts Observed in Real Time: From Catalysis-Induced Fluxionality to Catalytic Cycles.

摘要

The results from Dynamic Chemical and Structural Changes of Heterogeneous Catalysts Observed in Real Time: From Catalysis-Induced Fluxionality to Catalytic Cycles have been summarized including (1) construction/evaluation of a transmission infrared spectroscopy cell utilizing either a pulsed valve or laser to generate temporal perturbation that enables millisecond to microsecond time resolution; (2) millisecond-wide pulses to titrate kink, step and terrace sites, followed by their removal with pulsed hydrogen in order to differentiate the rate of CO methanation on a Pd/SiO2 catalyst; (3) development of an extended x-ray absorption spectroscopy technique to determine the number of surface Pd atoms with a particular coordination number utilizing inert gas adsorption; and (4) synthesis and characterization of bimetallated TiO2 nanorods for future studies as catalysts for total water splitting. The development of time-resolved infrared spectroscopy is still in its infancy for the study of chemical kinetics and dynamics in heterogeneous catalysis. Preliminary results with photolytic ethylene generation has provided promising results towards the identification of reaction intermediates during hydrogenation, and we continue to pursue these approaches for selective oxidation of olefins.