Design of mesoporous sulfated zirconia nanocrystals with dual Brønsted acid and Lewis acid

Sulfated ZrO 2 (S-ZrO 2 ) nanocrystals with a pure tetragonal phase and mesopores were designed by calcination of sulfated UiO-66. Benefiting from the inhibitory effect of organic linkers and sulfate ions on the growth of crystals during the pyrolysis process, S-ZrO 2 , derived from sulfated UiO-66, is composed of nano-sized crystals with a size of about 5 nm. In addition, the released gases from the decomposition of organic linkers enable S-ZrO 2 with mesopores, avoiding the severe agglomeration of ZrO 2 nanocrystals. As a result, the as-synthesized S-ZrO 2 nanocrystals can function as the promising catalysts containing dual Brønsted acidic and Lewis acidic sites to display a good catalytic activity in the esterification reaction of propanoic acid with methanol. In particular, a good conversion of 96.8 % for propanoic acid was achieved at 7 h, higher than that of commercial ZrO 2 -based sulfated ZrO 2 (74 %) and pristine UiO-66 (24 %).