Correlations between surface structure and catalytic activity/selectivity. Progress report, January 1, 1994--December 31, 1994

Abstract

The primary focus of this research is to address those issues which are keys to understanding the relationship between surface properties and catalytic activity/selectivity. These issues also impact the understanding of the origins of the enhanced catalytic properties of mixed-metal catalysts. The experimental approach utilizes a microcatalytic reactor contiguous to a surface analysis system, an arrangement which allows in vacuo transfer of the catalyst from one chamber to the other. Surface techniques being used include Auger (AES), ultraviolet and X-ray photoemission spectroscopy (UPS and XPS), temperature programmed desorption (TPD), low energy electron diffraction (LEED), high resolution electron energy loss spectroscopy (HREELS), infrared reflection absorption spectroscopy (IRAS), and scanning tunneling and atomic force microscopy (STM and AFM). This research program builds upon previous experience relating the results of single crystal kinetic measurements with the results obtained with supported analogs. As well, the authors are exploiting recent work on the preparation, the characterization, and the determination of the catalytic properties of ultra-thin metal and metal oxide films. Specifically, the program is proceeding toward three goals: (1) the study of the unique catalytic properties of ultrathin metal films; (2) the investigation of the critical ensemble size requirements for principal catalytic reaction types; andmore » (3) the modelling of supported catalysts using ultra-thin planar oxide surfaces.« less