Kinetics and diffusional limitations in nanostructured heterogeneous catalyst with controlled pore texture

Nanostructured carbon xerogels with controlled pore texture are used as catalyst support for the oxidation in aqueous phase of D-glucose into D-gluconic acid on Pd-Bi/C catalysts. X-ray photoelectron spectroscopy shows that metal active sites are not homogeneously dispersed in the spherical support particle but are concentrated in an external spherical layer. The influence of mass transfers on reaction kinetics is highlighted. Internal diffusional limitations are quantified using the Weisz modulus. It is shown that measuring the true kinetic reaction rate implies to choose the experimental conditions within a small range of values. (C) 2010 Elsevier B.V. All rights reserved