Catalysis on microstructured bimetallic surfaces

Microstructured bimetallic Pt/Rh and Pt/Ti surfaces have been employed to study the dynamics of catalytic NO reduction and the O-2+H-2 reaction at low pressure (p<10(-3) mbar). Photoelectron emission microscopy and scanning photoelectron microscopy were used as spatially resolved in situ methods to image the local work function changes and to identify chemical changes in the substrate and in the adsorbate layer. It is shown that diffusional coupling leads to dynamic effects which are dependent on the macroscopic size (&mu;m range). With alkali metals on the surface, stationary patterns form whose mechanism of formation has been studied in detail. (C) 2002 American Institute of Physics.