화학공학소재연구정보센터
Catalysis Letters, Vol.83, No.1-2, 71-78, 2002
Vibrational non-equilibrium at catalytic surfaces
Inclusion in a surface reaction scheme of fast V-V up-pumping processes, bound to the anharmornicity of the vibrational levels of mobile surface species, can lead to quasi-steady states characterized by non-equilibrium Treanor vibrational distribution functions, with nu > 0 levels over-populated with respect to Boltzmann equilibrium. Non-equilibrium distributions are shown to depend on the intensity of the chemisorption processes active under the working conditions of the catalyst. The shape of these distributions determines the surface reaction rate, and reactions with widely different "true" activation energies can proceed at comparable speeds at finite surface temperatures. This provides an interpretation of the isokinetic relationship in heterogeneous catalysis based on a non-Boltzmann picture of the catalytic surface.