TY - JOUR

T1 - Oxidation catalysts prepared by mechanically and thermally induced spreading of Sb2O3 and V2O5 on TiO2

AU - Schubert, U. A.

AU - Spengler, J.

AU - Grasselli, R. K.

AU - Pillep, B.

AU - Behrens, Peter

AU - Knözinger, H.

N1 - Funding information: This work was financially suplx~ed by the Bayerische Forschungsverbund Katalyse FORKAT, by the Deutsche Forsehungsgemeinschaft (SFB 338) and by the Fond der Chemischen Industrie. R.K. Grasselli gratefully acknowledges the Alexander von Humboldt Stiftung for receipt of a Humboldt Research Prize.

PY - 1997/1/1

Y1 - 1997/1/1

N2 - Vanadium and antimony oxides are essential parts of some industrial catalysts for the selective oxidation of substituted aromatics to the corresponding anhydrides [1] and the selective oxidation of paraffins to the corresponding unsaturated acids and nitriles [2]. These catalysts are generally prepared by impregnation or coprecipitation methods. It was the objective of this study to investigate an alternate method of catalyst preparation, a method based on a solventless ball-milling technique, aimed at adequately dispersing the active catalyst ingredients on a given support material to yield acceptably effective catalysts. Specifically, the spreading and the dispersion of V-oxide, Sb-oxide, and V-Sb-oxides on TiO2 supports were investigated by means of the ball-milling technique, and the so prepared materials compared to conventionally prepared materials. The tribe-chemical process of the former method was followed by spectroscopic techniques including XPS, XANES, and TPR, which revealed that active phase dispersions comparable to those obtained by conventional preparation techniques can readily be achieved by the milling method. It was further observed that the addition of small amounts of water during the milling greatly enhances the rate of the dispersion process. Catalytic tests of a V-oxide-on-TiO2 composition reveal that the selective oxidation of o-xylene to phthalic anhydride (PA) proceeds at comparable levels for compositions prepared by either the milling or the impregnation method. Therefore, it is concluded that the solventless ball-milling technique is also an effective alternative method for the preparation of selective oxidation catalysts.

AB - Vanadium and antimony oxides are essential parts of some industrial catalysts for the selective oxidation of substituted aromatics to the corresponding anhydrides [1] and the selective oxidation of paraffins to the corresponding unsaturated acids and nitriles [2]. These catalysts are generally prepared by impregnation or coprecipitation methods. It was the objective of this study to investigate an alternate method of catalyst preparation, a method based on a solventless ball-milling technique, aimed at adequately dispersing the active catalyst ingredients on a given support material to yield acceptably effective catalysts. Specifically, the spreading and the dispersion of V-oxide, Sb-oxide, and V-Sb-oxides on TiO2 supports were investigated by means of the ball-milling technique, and the so prepared materials compared to conventionally prepared materials. The tribe-chemical process of the former method was followed by spectroscopic techniques including XPS, XANES, and TPR, which revealed that active phase dispersions comparable to those obtained by conventional preparation techniques can readily be achieved by the milling method. It was further observed that the addition of small amounts of water during the milling greatly enhances the rate of the dispersion process. Catalytic tests of a V-oxide-on-TiO2 composition reveal that the selective oxidation of o-xylene to phthalic anhydride (PA) proceeds at comparable levels for compositions prepared by either the milling or the impregnation method. Therefore, it is concluded that the solventless ball-milling technique is also an effective alternative method for the preparation of selective oxidation catalysts.

UR - http://www.scopus.com/inward/record.url?scp=33750891186&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:33750891186

VL - 110

SP - 817

EP - 827

JO - Studies in Surface Science and Catalysis

JF - Studies in Surface Science and Catalysis

SN - 0167-2991

ER -