Au nanoparticles confined in self-assembled Zn(ii) metal–organic cubane cages for light-driven conversion of furfural to 2-methyl furan in biofuel production

Abstract

A polyoxometalate Zn(II) cubane cage with intrinsic confined spaces constructed by the self-assembly of tetrametallic cubane clusters was obtained and utilized as a skeletal support for the encapsulation of gold nanoparticles. AuNP-encapsulated Zn(II) cubane cages (ZnCC@AuNPs) were characterized using FTIR, TGA, BET, SEM, TEM, XPS, and PXRD analysis. The catalytic activity of ZnCC@AuNPs for the hydrogenation of furfural to 2-methyl furan, which is an active precursor for biofuel production, was investigated. The anchored AuNPs generate Au–H species under visible light and catalyse the reaction in 2-propanol at 60 °C, yielding >99% of the product in just 1.5 h. The reaction kinetics and mechanism were confirmed by in situ ATR-IR and DFT studies. The parameter optimization suggested exceptional chemical stability and reusability of ZnCC@AuNPs as a catalyst without any agglomeration even after several cycles of use. These intriguing features are suitable for developing sustainably viable catalysts for the biomass refinery industry.