Ligand-Enhanced Reduction of Perchlorate in Water with Heterogeneous Re−Pd/C Catalysts

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• 作者：Keith D. Hurley ; Yunxia Zhang ; John R. Shapley
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：October 14, 2009
• 年：2009
• 卷：131
• 期：40
• 页码：14172-14173
• 全文大小：120K
• 年卷期：v.131,no.40(October 14, 2009)
• ISSN：1520-5126

文摘

New bimetallic heterogeneous catalysts for the reduction of perchlorate in water with dihydrogen have been prepared in two ways: (1) by impregnating 5 wt % Pd on activated carbon powder with one of the complexes trans-[ReO₂(py-X)₄]⁺ (py-X = 4-substituted pyridine; X = H, Me, OMe, NMe₂) or (2) by adsorbing perrhenate onto the Pd/C powder in the presence of the pyridine ligand under a hydrogen atmosphere. Both sets of catalysts are highly active at pH 2.7−3.0 (HCl), with observed rates increasing with varying X in the order H < Me < OMe < NMe₂, which supports a rate-determining oxygen atom transfer reaction involving the Re(V) centers. However, the materials prepared by method (1) show evidence of facile formation of perrhenate from handling under ambient conditions. A system prepared by method (2) with 2 equiv of dimethylaminopyridine per Re is especially active and stable up to pH 4.5.