Superacid Catalyst SO₄^2-/ZrO^2-La₂O₃ Prepared by Ultrasonic Co-precipitation and Low Temperature Aging

Sulfated zirconia-lanthana (SO₄^2-/ZrO^2-La₂O₃) precursors were prepared by ultrasonic co-precipitation method and followed by aging at different temperature. The precursors weretreated by 0.5 mol/L H₂SO₄. Samples of SO₄^2-/ZrO^2-La₂O₃nano-crystalline catalysts wereobtained by baking the treated precursors at different temperatures. The acidic properties ofSO₄^2-/ZrO^2-La₂O₃ were tested by the Hammett indicator method. The phase composition,specific area, particle structure, and surface state were characterized by X-ray diffraction,BET, transmission electron microscopy, infrared spectrum, and X-ray photoelectron spec-troscopy. The catalytic activities were estimated by esterification of acetic acid with glycerin.It was shown that the catalyst prepared by ultrasonic stirring and low temperature (-15 ºC)exhibited highly active sites and high catalytic property.