Mn(II)-Based Catalysts Supported on Nanocarbon-Coated Silica Nanoparticles for Alkene Epoxidation
journal contributionposted on 03.06.2020, 19:17 by Fotini Fragou, Constantinos Moularas, Katarzyna Adamska, Yiannis Deligiannakis, Maria Louloudi
Hybrid nanocatalytic materials were synthesized by the covalent grafting of a MnII-catalyst onto nanocarbon-coated SiO2 (SiO2@nC) particles. Using flame spray pyrolysis (FSP), SiO2@C-nanodots and SiO2@C-nanosheets were engineered. These SiO2@nC nanosupports are appropriate for grafting via a cost-effective protocol that avoids the hard-acid treatment process. The functionalized MnIIL[SiO2@nC] nanocatalysts show enhanced epoxidation catalytic efficiency for a broad range of olefin substrates. The analysis of catalytic, spectroscopic, and hydrophobicity data reveals that the interfacial characteristics and hydrophobicity of the nanocarbon support are determinant in the control of the catalytic turnover frequency (TOF). This beneficial effect of nanocarbon is attributed to two mechanisms: (i) the nanocarbon coating with enhanced hydrophobicity enhances the catalytic activity by repelling the water molecules produced during the catalytic reaction, and (ii) the nanocarbon coating enables the organic lipophilic substrates to approach the active catalytic center and enhance the TOFs.