Supercritical carbon dioxide anchored highly dispersed silver nanoparticles on 4A-zeolite and selective oxidation of styrene performance

We developed a facile and new method for the production of a 4A-zeolite supported silver nanoparticle (Ag NP) composite catalyst using supercritical carbon dioxide (scCO(2)). The small (3-6 nm) and highly dispersed silver nanoparticles were formed on the 4A-zeolite with the assistance of scCO(2) and hydrogen reduction. The anchored Ag NPs are smaller in size and more uniform in distribution on the 4A-zeolite, and favor a wide range of physical and chemical properties. In order to test the properties of the synthesized composite catalyst, the selective oxidation of styrene was introduced into the experiment. The composite catalyst synthesized by this new method exhibited excellent catalytic properties in the selective oxidation reaction of styrene compared with previous reports. Furthermore, two kinds of important chemical product, styrene oxide (SO) and benzaldehyde (BZ), could be controlled selectively by changing the oxidants and solvents used.