Binary collision growth of supported metal catalyst particles

A model is presented for binary collision growth of supported metal catalyst particles. The particles are fractal aggregates of smaller particles sintering during the aggregation, The experimental fact is confirmed by Monte Carlo simulations, that the size distribution is self-preserving and lognormal. An interdependence is found connecting fractal dimension, the exponent characterizing the size dependence of the diffusion coefficient, and the width of the size distribution, represented by the geometric standard deviation of the aggregate radius distribution. The model is confirmed by experimental data available in literature, The size distribution depends on the exponent characterizing mass dependence of the aggregate activity. The model is complete if sintering does not alter the general topology of aggregates and then may be used to determine the exponent in mass dependence of the diffusion coefficient. Otherwise it could be helpful to identify the unknown mechanisms of aggregate migration and compaction on the basis of experimentally obtained size distribution of metal particles on a support. (C) 2002 Elsevier Science B.V. All rights reserved.