Decomposition of hydrogen peroxide: influence of the shape of catalyst support

Abstract

In the present paper, an experimental study of catalytic decomposition of aqueous hydrogen peroxide was investigated. This study including: -the preparation of platinum based catalysts supported on γ-alumina (grains and pellets). -the evaluation of catalytic activity using two reactors laboratory scale.The characterization of these catalysts by X-ray diffraction, electron microscopy and elemental analysis before and after catalytic activity. Two main parameters were studied: internal (pellets and grains) and external (grains size) surface diffusion. The characterization results of all prepared catalysts are showed a homogeneous distribution of platinum particles (average size 1.6 nm) on the support surface. The kinetic study of the catalytic decomposition reaction of H2O2 (2 wt.%) showed that all platinum based catalysts follow a first order kinetic decomposition reaction. Moreover, the grain catalysts form shape show much higher activity than the pellet catalysts leading to a rapid decomposition of H2O2. Finally, the grain size of the catalysts has a strong influence on the reaction rate of decomposition reaction. For an equivalent amount of catalyst, the external surface increases when the grain size of the catalysts decreases which leads to a higher catalytic activity.