Abstract:
MnO
x/ZrO
2-Cr
2O
3 catalysts were prepared by cocurrent coprecipitation and impregnation. The structure and surface properties of the catalyst were characterized by X-ray diffraction (XRD), N
2 physical adsorption (BET), hydrogen temperature programmed reduction (H
2-TPR), and X-ray photoelectron spectroscopy (XPS). These results showed that the addition of Cr led to the transformation of ZrO
2 crystal form from
m-ZrO
2 to
t-ZrO
2. With the increase of Cr content, the BET of the composite oxide ZrO
2-Cr
2O
3 increased gradually, the average pore size decreased and the pore structure also changed. The impregnation of Mn caused the migration of Cr in the ZrO
2-Cr
2O
3 composite oxide, and promoted the transformation of the ZrO
2 crystal form from
m-ZrO
2 to
t-ZrO
2, the BET and pore structure of the catalyst changed also. The conversion and selectivity of MnO
x/ZrO
2-Cr
2O
3 catalysts containing 4% Mn and 2.5% Cr for methyl benzoate hydrogenation were 93.86% and 86.05%, respectively.