Influence of the Morphological and Chemical Properties of Nanosized Metal Oxides on Catalytic Efficiency for the Cycloaddition Reaction of CO₂ to Epoxides

Abstract

Metal oxides represent “workhorse catalysts” for the chemical industry with multifarious applications in dehydrogenation, metathesis, transesterification, and combustion reactions. It is therefore crucial, for each given catalytic process, to investigate the impact of morphological and physicochemical properties on catalytic performance. Metal oxide materials are being increasingly applied as inexpensive catalytic materials for the cycloaddition of CO2 to epoxides but the correlation between the chemical properties of the metal oxides and their catalytic activity has not been systematically investigated. In this work, we prepared nanostructured tin (IV) oxide (SnO2) and zinc oxide (ZnO) materials with different morphologies such as quantum dots (QDs), nanowires (NWs), microdisks (µDs) and nanoplates (NPLs). Following characterization, these materials were investigated, in combination with low amounts of tetrabutylammonium iodide (TBAI) as a nucleophile, for the CO2 cycloaddition to styrene oxide (SO) yielding cyclic styrene carbonate (SC) under atmospheric pressure. The correlation between catalytic performance, surface area, acidity and basicity was investigated and discussed.