TPR investigations on the reducibility of Cu supported on Al2O3, zeolite Y and SAPO-5

被引:54
作者
Dang Lanh Huang [1 ]
Thi Thuy Hanh Dang [1 ]
Engeldinger, Jana [1 ]
Schneider, Matthias [1 ]
Radnik, Joerg [1 ]
Richter, Manfred [1 ]
Martin, Andreas [1 ]
机构
[1] Univ Rostock, Leibniz Inst Katalyse eV, D-18059 Rostock, Germany
关键词
TPR; Cu reducibility; Cu oxidation state; Cu/Al2O3; Cu/Y; Cu/SAPO-5; TEMPERATURE-PROGRAMMED-REDUCTION; GAS-PHASE CARBONYLATION; ELECTRON-SPIN-RESONANCE; TRANSITION-METAL IONS; MOLECULAR-SIEVES; ADSORBATE INTERACTIONS; DIMETHYL CARBONATE; OXIDATION-STATES; CATALYSTS; METHANOL;
D O I
10.1016/j.jssc.2011.05.042
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Reducibility of Cu supported on Al2O3, zeolite Y and silicoaluminophosphate SAPO-5 has been investigated in dependence on the Cu content using a method combining conventional temperature programmed reduction (TPR) by hydrogen with reoxidation in N2O followed by a second the so-called surface-TPR (s-TPR). The method enables discrimination and a quantitative estimation of the Cu oxidation states +2, +1 and 0. The quantitative results show that the initial oxidation state of Cu after calcination in air at 400 degrees C, independent on the nature of the support, is predominantly +2. Cu2+ supported on Al2O3 is quantitatively reduced by hydrogen to metallic Cu-0. Comparing the TPR of the samples calcined in air and that of samples additionally pre-treated in argon reveals that in zeolite Y and SAPO-5 Cu2+ cations are stabilized as weakly and strongly forms. In both systems, strongly stabilized Cu2+ ions are not auto-reduced by pre-treatment in argon at 650 degrees C, but are reduced in hydrogen to form Cu+. The weakly stabilized Cu2+ ions, in contrast, may be auto-reduced by pre-treatment in argon at 650 degrees C forming Cu+ but are reduced in hydrogen to metallic Cu-0. (C) 2011 Elsevier Inc. All rights reserved.
引用
收藏
页码:1915 / 1923
页数:9
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