MOF-derived zirconia-supported Keggin heteropoly acid nanoporous hybrids as a reusable catalyst for methyl oleate production

Abstract

In this study, a series of nanoporous HSiW@ZrO₂ hybrids were synthesized using a zirconium metal–organic framework UiO-66 as a precursor towards biodiesel production. The structural and morphological properties of the obtained hybrids were characterized by the wide-angle XRD, FTIR, SEM, TEM, N₂ adsorption/desorption, and NH₃-TPD methods. Moreover, their catalytic activity in terms of calcination temperature during preparation was investigated, and the HSiW@ZrO₂ hybrids calcinated at 300 °C exhibited the highest activity and the oleic acid (OA) conversion of 94.0% owing to the presence of the relatively high surface area, appropriate pore size and strong acidity. It was also revealed that the hybrids maintained as high as 82.0% even after nine cycles. Intriguingly, the nanoporous catalysts were found to exhibit excellent catalytic activity towards the esterification of the high acid value of Jatropha curcas oil.