Remarkable support crystal phase effect in Au/FeO_x catalyzed oxidation of 1,4-butanediol to γ-butyrolactone

摘要

Iron oxides in different crystal forms with identical particle size and morphology are employed as supports for gold catalysts. By using the oxidative dehydrogenation of 1,4-butanediol to γ-butyrolactone as the probe reaction, combined with some characterizations such as XRD, TEM, XPS, and H_2-TPR, support effect of Au/FeO_x catalysts is established in this study. Turnover frequency value follows the order Au/Fe_3O_4 > Au/α-Fe_2O_3 > Au/γ-Fe_2O_3. Size effect of Au/Fe_3O_4 catalysts with different gold particle size distributions obtained by treating under different atmospheres is also studied for comparison, and the results imply the slight effect of gold particle size. Variation in catalytic behavior of gold catalysts on different iron-oxide supports originates from the discrepancy in gold geometry, gold oxidation state, and gold-support contact interface structures which are caused by difference in support intrinsic properties such as microcrystalline structure and oxidation state.