Frozen slurry catalytic reactor: A new structured catalyst for transient studies in liquid phase

In this study we present a method to prepare catalytic polymer membranes by incorporating mono-dispersed Pt/SiO2 catalyst particles in an EVAL polymer porous matrix via immersion phase separation. Addition of a relatively high concentration (65 wt%) of catalyst particles is preventing the formation of macro-voids, improving both mechanical stability of the membranes as well as improving homogeneity of the liquid flow distribution through the membrane. The catalyst particles remain intact during the preparation procedure. The catalyst particles are physically immobilized throughout the membrane, entrapped in the pores, preventing channeling that would occur when flowing through an equivalent shallow fixed bed. Furthermore, the novel frozen-slurry-like morphology results in significant lower pressure drop as compared to a fixed bed with identical diameter and containing the same amount of catalyst particles. Low pressure drop, despite very small support particle size, is an important technical advantage for operating a new transient method in liquid phase. The platinum particles are proven to be highly accessible in the swollen state, i.e. in liquid phase, as demonstrated both by the catalytic activity of the Pt/SiO2 loaded membranes for glucose oxidation as well as by the observation that H2–O2 titrations confirms that close to all platinum surface atoms contribute.

This work described a new method to distribute Pt/silica slurry catalyst particles in space, using a polymer membrane. The result is that pressure drop is decreased as compared to a packed bed of identical particles, which especially important for transient operated liquid-reactors. It is shown that the polymer does not compromise the accessibility of the Pt surface. Figure optionsDownload as PowerPoint slide