REACTIONS AT WELL-DEFINED SURFACES

Early work (mainly by Langmuir) has erected the conceptual framework for chemical reactions occurring at well-defined solid surfaces and forming the basis for heterogeneous catalysis but experimental verification has been enabled only during the past three decades. My first contribution to Surface Science appeared in 1967 and concerned the interactions of various molecules with Cu single-crystal surfaces, mainly by using LEED. This technique revealed not only structural information, but also was applicable for studying kinetic phenomena as exemplified somewhat later with the catalytic oxidation of carbon monoxide on Pd(110). Some of the questions raised in this early work could be answered only quite recently or were revealed to be even more complex than anticipated. This holds in particular for catalytic reactions under steady-state conditions for which a wealth of phenomena of nonlinear dynamics, ranging from oscillatory or chaotic kinetics to spatio-temporal pattern formation, may occur.