The flexible surface: new techniques for molecular level studies of time dependent changes in metal surface structure and adsorbate structure during catalytic reactions

摘要: The new model that emerges from the results of recent surface science studies is one a dynamic, flexible undergoes rapid adsorbate-induced restructuring on time scale chemisorption, or at times, slower catalytic reactions, atom diffusion-controlled faceting, solid state reactions. Many unique chemical properties can be associated with its ability to restructure rapidly as adsorbate bonds form break. Surface specific vibrational spectroscopy by sum frequency generation (SFG) and high pressure/high temperature scanning tunneling microscopy (STM) are two independent but complimentary techniques which permit molecular level surfaces under dynamic conditions pressures. application these allows in situ analysis reactive during conditions. These have been used study ethylene propylene hydrogenation platinum surfaces. investigations provide definitive evidence for physisorbed intermediates, stagnant chemisorbed species, an unreconstructed catalysis. role carbon-containing overlayers covering reactions has identified. A detailed mechanism proposed.