Aluminum/Tin-doped UiO-66 as Lewis acid catalysts for enhanced glucose isomerization to fructose

Glucose isomerization into fructose is the dominant reaction path for biomass conversion . Lewis acidic aluminum or tin were firstly impregnated in microporous UiO-66 for remarkably enhanced glucose isomerization. Al@UiO-66 achieved 37.5% fructose yield with a 63.9% selectivity with no obvious leaching of aluminum while Sn@UiO-66 failed the leaching test. The 27 Al NMR and XPS spectra of Al@UiO-66 demonstrated the complex environment of aluminum in UiO-66 involving the chains of aluminum octahedra and the Al–O–C structure, which contributed to the enhanced Lewis acidity and promoted performance of the catalyst.