Design and fabrication of a structured catalytic reactor at micrometer scale: Example of methylcyclohexane dehydrogenation

A silicon micro-structured reactor has been designed for gas-solid heterogeneous catalysis, in particular for the dehydrogenation of methylcyclohexane. Two types of catalyst deposition on silicon have been evaluated: the first consists of a washcoat deposition of a (gamma) -alumina layer followed by Pt impregnation, the second is a cathodic Pt film sputtering. The Pt/Al2O3 catalyst reveals a higher activity for this reaction and was selected for further investigation. Since the micro-structured reactor is composed of pillars of typical dimension 5 × 100 µm, a special washcoat method has been developed leading to the controlled deposition of a homogeneous (gamma)-alumina layer of thickness <1 (mu)m. Because the dehydrogenation reaction is endothermic (204 kJ mol^-1) and conducted at ca. 380 °C, heaters have been integrated using screen-printing methods. FEMLAB simulations have helped to integrate the hot reaction zone and a low temperature section for connectors (<200 °C) in a 10 × 30 mm chip.