Model studies of catalysis with microstructured bimetallic surfaces

Microstructured bimetallic surfaces prepared by optical lithography allow u s to study dynamic effects under low pressure conditions with spatially res olving in situ techniques such as photoelectron emission microscopy (PEEM) and scanning photoelectron microscopy (SPEM). Reactions of the automotive c atalytic converter on microstructured Pt/Rh surfaces have been investigated . The following effects have been observed: macroscopic size effects in rea ctivity due to diffusional coupling, front nucleation at Pt/Rh domain bound aries and the formation of Stationary concentration patterns due to reversi ble adsorbate-induced segregation in bimetallic alloyed films. The experime nts are complemented by simulations of the reactions for composite media ai med at "microchemical engineering" of catalytic surfaces. (C) 2000 Elsevier Science B.V. All rights reserved.