Abstract

A Microfluidics Platform for Heterogeneous Catalysis in Wall-Coated Flow Reactors

Dominik Scherrer, PhD Student, University of Basel

On-chip flow microreactors may increase space-time efficiency for reaction screening and compound library synthesis (e.g. for drug discovery) as they enable miniaturization and process automation. Cutting-edge microfabrication of chemically inert silicon-based microfluidics compatible with MEMS and CMOS technology allows novel reactor designs and thus the exploration of new compounds and chemical reactivities. Milli- and microfluidic devices are engineered for solid-phase synthesis of catalytically active surfaces and these wall-coated microreactors are used to screen single- and multistep chemical reactions with immobilized organocatalysts and organometallic catalysts. In particular, on-chip modules allow precise reaction control, site-selective electrochemical surface functionalization as well as field-enhanced optical surface analytics. In contrast to frequently utilized glass channel walls as catalyst adhesion layers, this work uses metallic coatings along microchannels that permit the formation of segregated thin-films patterns. Differently functionalized surfaces can thus be synthesized in a single channel. The metallic catalyst adhesion layer acts as electrode material for both electrosynthesis and electrochemical analysis. In addition, microfabricated resonant plasmonic nanohole arrays embedded in the electrodes were designed to characterize catalyst monolayers by surface-enhanced Raman spectroscopy (SERS).