Porous ceramic mesoreactors: A new approach for gas–liquid contacting in multiphase microreaction technology

In this study a concept for gas–liquid–solid (G–L–S) microreaction technology was developed and optimized which ensures that the gaseous and liquid reactants directly meet at the solid catalyst surface with a simple contacting approach. Fabrication, catalyst deposition and surface modification steps were carried out to develop porous ceramic (alumina—Al2O3) mesoreactors. In order to realize liquid flow inside the intrinsically hydrophilic porous reactor channel and to obtain a stabilized gas–liquid–solid interface different surface modification (hydrophobization) strategies were successfully implemented. Catalytically active reactors with varying surface properties along the cross-section were obtained and their performance was tested for nitrite hydrogenation as a G–L–S model reaction. Results showed that the performance of the reactor could be drastically enhanced by tuning the surface properties. With the proposed concept, even at dilute concentrations of the gaseous reactant, the reactor performance remained constant.