![\"\"](\"https:\/\/micromeritics.com.cn\/wp-content\/uploads\/2024\/11\/Characterization-of-Vanadia-Catalysts-Supported-on-Different-Carriers-by-TPD-TPR-1.png\")
<\/figure>\n\n\n\nExperimental<\/h3>\n\n\n\nCatalyst Preparation<\/h4>\n\n\n\n
Two systems of catalysts were prepared by the wet impregnation. They were indicated as VxA (for V2<\/sub>O5<\/sub>\/Al2<\/sub>O3<\/sub>) and VyT (for V2<\/sub>O5<\/sub>\/TiO2<\/sub>), where x and y are the loadings of vanadium expressed in wt. %. Alumina (BET surface area = 195 m2<\/sup>\/g) and Titania (BET surface area = 55 m2<\/sup>\/g) were impregnated with vanadium oxalate aqueous solution, followed by drying at 110 \u00b0C for 14h and calcination at 650 \u00baC and at 450 \u00b0C (for VxA and VyT, respectively) for 3h.<\/p>\n\n\n\n Temperature- Programmed Reduction (TPR) with hydrogen and Temperature-Programmed Desorption (TPD) of NH3<\/sub> were carried out in a Micromeritics AutoChem II 2920 analyzer.<\/p>\n\n\n\n In the TPR experiments, the sample without pretreatment was reduced with a 10% H2<\/sub>\/Ar mixture (25 ml\/min) by heating at 10 \u00b0C\/min to 800 \u00b0C. In the TPD experiments, the sample, after decontaminating at 300 \u00b0C, was saturated with 10% NH3<\/sub>\/He (15 ml\/min) at 100 \u00b0C for 1h, and then was purged with pure He for 1h. For the desorption, it was heated (10 \u00b0C\/min) to 500 \u00b0C in flowing He (25 ml\/min).<\/p>\n\n\n\n NH3<\/sub> TPD of VxA contrasted with that of VyT. When the loadings of vanadia rose, the NH3<\/sub> TPD profiles of VxA shifted to low temperature, showing that the amount of weak acid sites increased and the amount of medium and strong acid sites decreased. Contrarily, on NH3<\/sub> TPD profiles of VyT, the strong acid sites increased as loadings of vanadia increased. Above monolayer (V10T), a third peak appeared at the middle temperature range.<\/p>\n\n\n\n The TPR of V2<\/sub>O5<\/sub>\/Al2<\/sub>O3<\/sub> showed only one peak at lower temperature. It was attributed to the reduction of the monovanadate species. There are two reduction peaks in the TPR profiles of V2<\/sub>O5<\/sub>\/TiO2<\/sub> under monolayer coverage (V2T and V8T): they were attributed to the reduction of mono- and poly-vanadate species. When the coverage was over the monolayer (V10T), a third peak appeared at higher temperature, it might be the reduction of V2<\/sub>O5<\/sub> crystallites.<\/p>\n\n\n\n [1] B. Grzybowska-Swierkosz, Appl. Catal.<\/em> A, 157 (1997) 263- 310 Pham Thanh Huyen, Nguyen Anh Vu, Nguyen Minh Hien, Le Van Hieu, Dao Van Tuong, Hoang Trong Yem. Petrochemical and Catalysis Material Laboratory, Hanoi University of Technology, Hanoi, Vietnam Introduction Since V2O5\/TiO2 catalysts were successful in the oxidation of oxylene, vanadium-containing catalysts were widely used in the oxidation of other aromatic and paraffinic hydrocarbons [1]. […]<\/p>\n","protected":false},"featured_media":0,"parent":0,"template":"","meta":{"_acf_changed":false},"methods":[25],"resource_type":[8],"class_list":["post-6561","resources","type-resources","status-publish","hentry","methods-chemisorption","resource_type-application-notes"],"acf":[],"_links":{"self":[{"href":"https:\/\/micromeritics.com.cn\/en\/wp-json\/wp\/v2\/resources\/6561","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/micromeritics.com.cn\/en\/wp-json\/wp\/v2\/resources"}],"about":[{"href":"https:\/\/micromeritics.com.cn\/en\/wp-json\/wp\/v2\/types\/resources"}],"wp:attachment":[{"href":"https:\/\/micromeritics.com.cn\/en\/wp-json\/wp\/v2\/media?parent=6561"}],"wp:term":[{"taxonomy":"methods","embeddable":true,"href":"https:\/\/micromeritics.com.cn\/en\/wp-json\/wp\/v2\/methods?post=6561"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/micromeritics.com.cn\/en\/wp-json\/wp\/v2\/resource_type?post=6561"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Characterization of Catalysts<\/h4>\n\n\n\n
Results and Discussion<\/h3>\n\n\n\n
![\"\"](\"https:\/\/micromeritics.com.cn\/wp-content\/uploads\/2024\/11\/Characterization-of-Vanadia-Catalysts-Supported-on-Different-Carriers-by-TPD-TPR-2.png\")
<\/figure>\n\n\n\nConclusions<\/h3>\n\n\n\n
\n
References<\/h4>\n\n\n\n
[2] M.A. Reiche, M. Maciejewski, A. Baiker, Catal. Today<\/em>, 56 (2000) 347-355
[3] J.W. Niemantsverdriet, Spectroscopy in Catalysis<\/em>, Wiley-VCH, 2000
[4] G. C. Bond, Appl. Catal.<\/em> A, 157 (1997) 91-103.<\/p>\n","protected":false},"excerpt":{"rendered":"