EPR study of S3 anion radicals on the surface of supported MoO3MgO, WO3MgO, and CrO3MgO catalysts》.pdf

JOURNAL OF CATALYSIS 55, 394-101 (19%) EPR Study of S,- Anion Radicals on the Surface of Supported MoOJMgO, WOJMgO, and CrOJMgO Catalysts A. K. KOLOSOV, V. A. SHVETS, N. D. CHUVYLKIN, AND V. B. KAZANSKY N. D. Zelinsky Institute of Organic Chemistry, Academy of Science of the U.S.S.R., Moscow, 117915, U.S.S.R. Received August 8, 1977 The formation of S3- anion radicals has been observed by the EPR method on the surface of supported MoOJMgO, CrOo/MgO, and WOa/MgO catalysts upon their interaction with HzS. Properties of S3- with respect to adsorption of different molecules such as 02, HtO, NH3, SOZ, C,H,, and H2S were also investigated. In the case of Hl a complex is shown to be formed between S3- and HJ. The nature of this complex and its structure is considered on the basis of experimental data and the results of quantum chemical calculations. INTRODUCTION EXPERIMENTAL In recent years the formation and The MoOs/MgO, CrOs/MgO, and WOs/ properties of sulfur-containing radicals on MgO (ml wt% of metal) were prepared the surface of catalysts have been widely by impregnation of magnesium oxide studied by EPR in connection with their (S = 30 m2 g-l) with aqueous solutions of tentative role in various catalytic reactions (NHJMo20,,