陽極酸化アルミナ層を担体とした白金/アルミナプレート状触媒の触媒有効係数

抄録

The effectiveness factor of Pt/Al₂O₃/Al plate catalyst was studied experimentally. The Pt/Al₂O₃ catalyst layer, prepared by anodic oxidation and hot-water treatment, had a porous structure and a narrow pore-size distribution. Catalyst porosity was about 0.5 and the mean pore radius about 2nm. The rate of cyclohexane dehydrogenation reaction increased with the thickness of Pt/Al₂O₃ catalyst layer to a certain peak, then the effectiveness factor decreased with thickness. This was because reactant diffusion into the catalyst layer was the controlling step. The observed reaction rate per apparent surface area is governed by the effective diffusion coefficient and the reaction rate constant. The reaction rate constant can be improved by augmenting the Pt content and Pt dispersion. The effective diffusion coefficient will be also improved with a large pore radius, which can be realized by controlling the anodized alumina layer pore structure.