AgNPs encapsulated by an amine-functionalized polymer nanocatalyst for CO2 fixation as a carboxylic acid and the oxidation of cyclohexane under ambient conditions

Abstract

Silver nanoparticles (AgNPs) embedded in a porous polystyrene material (AgNPs@m-PS-PC) were synthesized via the polymerization of polystyrene amine and 2-pyridinecarbaldehyde, followed by the reduction of silver nitrate in methanol. The structure and morphology of this porous material were characterized by powder X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy, Fourier-transform infrared, ultraviolet-visible, and atomic absorption spectroscopies, and thermogravimetric analysis. TEM showed that the AgNPs were well dispersed in the polymeric matrix, with dimensions of around 4–9 nm. This nanocatalyst showed activity, particularly for the green synthesis of valuable carboxylic acids by the carboxylation reaction of terminal alkynes with carbon dioxide under atmospheric pressure. Additionally, the catalyst displayed efficient catalytic activity for the oxidation of cyclohexane using hydrogen peroxide as the oxidising agent. The AgNPs@m-PS-PC nanocatalyst could be recycled five times and retained reliable efficiency.