Abstract

The kinetics of nitrate hydrogenation in water over niobia- and alumina-supported Pd-Cu catalysts were examined. A Langmuir-Hinshelwood kinetic model fitted concentration data, providing consistent kinetic and thermodynamic parameters. The kinetic model assumed a bimolecular surface reaction as the rate-determining step, with two types of sites. Pd-Cu/gamma-Al2O3 was active and selective under the reaction conditions. However, Pd-Cu/Nb2O5 deactivated during time on stream, and a deactivation function was added to the kinetic model to best fit the experimental data.