Nanosilver-decorated reduced graphene oxide for catalytic carboxylation of phenylacetylene with CO2

Nanosilver/reduced graphene oxide (AgNPs/rGO) nanocomposite by the green synthesis route was investigated using urea as a green reductor. The characterization of the AgNPs/rGO was confirmed by UV-Vis spectroscopy, FT-IR, XRD, Raman Spectroscopy, FE-SEM, Energy Dispersive X-ray (EDX), and TEM. The characterization result showed that the AgNPs/rGO was successfully synthesized by green reduction using urea, and the AgNPs were well-spread on the surface of the rGO. AgNPs/rGO nanocomposite was used as a catalyst towards the synthesize of phenylpropiolic acid from phenylacetylene carboxylation with CO2. The difference in the base used and reaction temperature influenced the carboxylation of phenylacetylene with CO2. The nanocomposite shows excellent selectivity towards phenylpropiolic acid. The highest conversion was obtained from the reaction using Na2CO3 at the temperature of 50 degrees C. Phenylpropiolic acid was formed as a major product with a high selectivity of 99.5%. The reusability of AgNPs/rGO nanocomposite as a carboxylation catalyst maintained an excellent selectivity above 99% even after third cycle.