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Abstract

In the present work, a novel droplet-based microfluidic scheme is developed to perform
chemical reactions. The chemical reactants are dispensed with precise volume control into pairs
of droplets produced via step-emulsification. The reaction is activated by merging the pairs of
droplets by a geometrical constriction and fast mixing inside the merged droplets. Furthermore,
the post-processing of the chemical products is also included within the microfluidic device.
This microfluidic reaction scheme allows performing precisely volume controlled reactions
with long and stable operation conditions without any clogging even if precipitates or sticky
gels are formed during the reaction. We demonstrate the potential of our microfluidic scheme
by producing mesoporous silica particles from a rapid gelation optimized sol-gel synthesis
route. The produced silica particles have a superior surface area of about 820 m2
g
−1
and a
narrow pore radius distribution around 2.4 nm. This microfluidic scheme is quite universal and
therefore, only the chemical recipe needed slight modifications to produce platinum doped silica
catalysts with superior catalytic behavior than commercially available catalysts.