Adsorption of Chlorobenzene on V2O5/γ-Al2O3 Catalyst

Isotherms of chlorobenzene adsorption on V₂O₅/-Al₂O₃ catalyst within the 0.07-18 Pa range of adsorbate partial pressure were measured, and certain thermodynamic characteristics of adsorption were found.     

Adsorption of chlorobenzene and benzene on γ-Al2O3/atl>

Adsorption of chlorobenzene and benzene on -Al₂O₃ was investigated in the 413--572 K temperature region at an adsorbate partial pressure ranging from 2 to 1000 Pa. The adsorption isotherms were measured and the isosteric heats and the entropy characteristics of adsorption were determined. The experimentally found and theoretically calculated entropy changes upon adsorption were compared. The mobility of the molecules of both adsorbates in the adsorption layer was limited with respect to that predicted by the ideal two-dimensional gas model. The mechanism of adsorption of benzene and chlorobenzene is discussed.     

异丁烷脱氢V2O5/γ-Al2O3催化剂的研究

五氧化二钒;异丁烷脱氢V2O5/γ-Al2O3催化剂的研究     

Effect of the Morphology of γ-Al2O3 Nanosized Particles on Their Adsorption Properties

Russian Journal of Physical Chemistry A - γ-Al2O3 porous nanostructures with different morphologies are prepared from an aluminitride nanopowder (obtained by electric explosion) by treatment...     

Stereoselective hydrogenation of 2-hexyne on Cu/γ-Al2O3 catalysts

The stereoselective hydrogenation of 2-hexyne in ethanol on Cu/-Al₂O₃ catalysts (1–40 % Cu) at 4–10 atm and 80–120 °C has been studied. The reaction affordscis-2-hexene as the only reaction product in 100 % yield at [Cu] 30 %. For samples with 20 % Cu, hydrogenation proceeds in parallel with absorption of H₂ by the catalyst.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1314–1315, July, 1993.     

In situ carbon nanotube synthesis by the reduction of NiO/γ-Al2O3 catalyst in methane

The synthesis of carbon nanotubes (CNTs) via chemical vapour deposition of methane on NiO/γ-Al2O3 catalyst has been investigated. The reduction behavior of NiO/γ-Al2O3 by methane was studied using thermogravimetric (TG) and X-ray diffraction (XRD) techniques. It was found that the NiO supported on γ-Al2O3, was reduced to Ni⁰ in methane atmosphere in the temperature range of 710--770 ℃. The catalytic activity of NiO/γ-Al2O3 for CNTs synthesis by in situ chemical vapour deposition of methane during the reduction was also investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the CNTs produced at various reduction temperatures. The results indicated that the reduction temperature exhibits obvious influence on the morphology and the yield of CNTs. CNTs with the diameter of about 20 nm were obtained at reduction temperature of 750 ℃, and higher reduction temperature (such as 800 and 850 ℃) led to an increase in CNTs diameter and a decrease in CNTs yield.     

V2O5/γ-Al2O3和V2O5/SiO2负载型催化剂对异丁烷的催化脱氢性能

V2O5/γ-Al2O3和V2O5/SiO2负载型催化剂对异丁烷的催化脱氢性能;V2O5/γ-Al2O3; V2O5/SiO2; 异丁烷; 脱氢     

Oxygen Spillover in the Conversion of NO on a Pd-Co/γ-Al2O3 Catalyst

Oxygen spillover was detected in the decomposition of NO on a Pd-Co/-Al₂O₃ catalyst obtained by the thermolysis of [Co(NH₃)₅Cl][PdCl₄].     

γ-Al2O3改性对AlCl3/γ-Al2O3催化剂性能的影响

采用HCl和NaOH改性γ-Al2O3载体制备AlCl3/γ-Al2O3固载催化剂,用吡啶-FTIR和吡啶-TPD技术分析了催化剂的表面酸性(酸中心类型、酸强度和酸量),并以1-癸烯齐聚作为探针反应,研究了催化剂的稳定性以及催化剂对聚合反应的影响.结果表明,催化剂含有两种酸类型,即Lewis酸和Br(o)nsted酸,与未改性的催化剂相比,氢氧化钠改性载体制备的催化剂,酸量增大了47％,催化剂催化1-癸烯的齐聚反应活性增加了11.4％;而经盐酸改性制备的催化剂酸量增大112％,催化剂的活性增加了33.6％.酸强度依AlCl3/γ-Al2O3,AlCl3/γ-Al2O3(NaOH),AlCl3/γ-Al2O3 (HCl)的顺序增强.     

Effect of Pd content on the isomerization performance over Pd-S2O8 2−/ZrO2-Al2O3 catalyst

Research on Chemical Intermediates - The effect of Pd content on the performance of the Pd-S2O8 2?/ZrO2-Al2O3 solid superacid catalyst was studied using n-pentane isomerization as a probe...     

La2O3 promotional effect to Co3O4/γ-Al2O3 catalyst in the oxidative dehydrogenation of ethylbenzene with CO2 as soft oxidant

Co₃O₄/γ-Al₂O₃ catalysts with variable Co₃O₄ loadings (5–20 wt%) and deposition of 15% Co₃O₄ on La₂O₃/γ-Al₂O₃ were prepared by wet impregnation method. La₂O₃-γ-Al₂O₃ support with variable composition of La₂O₃ (2–6 wt%) were prepared by co-precipitation method. All the catalysts were tested for oxidative dehydrogenation of ethylbenzene with CO₂ as soft oxidant. Among the Co₃O₄/γ-Al₂O₃ catalysts, 15% Co₃O₄/γ-Al₂O₃ has shown good performance and hence this catalyst has been chosen to investigate the effect of La₂O₃ species. CO₂ pulse chemisorption data indicate more amount of CO₂ uptake over 15% Co₃O₄/4%La₂O₃/γ-Al₂O₃ catalyst which clearly indicates that this catalyst exhibits good performance in ethylbenzene dehydrogenation with CO₂ as soft oxidant because of reverse water gas shift reaction. Temperature programmed reduction studies indicate that the Co₃O₄ catalysts follow two step reduction mechanism from Co₃O₄ to CoO and then to Co and La₂O₃ promotional effect is visible through facile reduction of Co₃O₄ species. La₂O₃ doping has a vital influence in getting enhanced ethylbenzene conversion, styrene yield and alleviates catalyst deactivation compared to that of unpromoted Co₃O₄/γ-Al₂O₃ catalyst. TGA studies indicate the presence low amount coke deposition during time-on-stream over 15% Co₃O₄/4%La₂O₃/γ-Al₂O₃ catalyst compared to 15% Co₃O₄/γ-Al₂O₃ catalyst.     

Pd/Ce/γ-Al2O3和Pd/Ce/γ-Al2O3甲醇低温裂解催化剂

Methanol is an alternative fuel for automobiles in the future. Decomposition of methanol by on-board reforming into H2 and CO as the feed for the engine has received increasing attention owing to energy saving and environmentally benign aim[1,2]. To meet the requirements of the process, new catalysts with high activity at low temperatures are indispensable. Several catalytic systems have been evaluated for methanol decomposition, but high reaction temperature and side reactions were always problems[3].     

TG Study of the Dispersion Threshold of Mn2O3 on γ-Al2O3

Mn₂O₃/-Al₂O₃ catalysts were prepared by the impregnation method, and the maximum monolayer dispersion capacity or dispersion threshold value of Mn₂O₃ on the surface of -Al₂O₃ was determined to be 13.08% from the decomposition mass loss of supported Mn(NO₃)₂ in the monolayer state. This was compared with the values estimated from a close-packed monolayer model and an interaction model. It was confirmed that the high activities and selectivities of the catalysts for benzoic acid hydrogenation to benzaldehyde are due to the monolayer dispersion of the Mn₂O₃ on the surface of -Al₂O₃.This revised version was published online in November 2005 with corrections to the Cover Date.     

Conversion of Rapeseed Oil to Biodiesel on KF/γ-Al2O3 CATALYST

Theoretical and Experimental Chemistry - It is shown that the KF/γ-Al2O3 catalyst obtained by the sol–gel method has a greater activity in the process of transesterification of methanol...     

镧对V2O5/γ-Al2O3催化剂在异丁烷脱氢中活性的影响

V2O5／γ-Al2O3是用于异丁烷脱氢的新型催化剂，引入适量的镧不仅可改善活性组分的分散度，提高催化脱氢活性，而且还增强了催化剂的抗积炭能力，通过FTIR，BET，TG，TPR和TEM等手段研究了镧对催化剂性能的影响。     

The remarkable enhancement of CO-pretreated CuO-Mn2O3/γ-Al2O3 supported catalyst for the reduction of NO with CO: the formation of surface synergetic oxygen vacancy

NO reduction by CO was investigated over CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuOMn2O3/γ-Al2O3 model catalysts before and after CO pretreatment at 300 °C. The CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst exhibited higher catalytic activity than did the other catalysts. Based on X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflectance spectroscopy (DRS), Raman, and H2-temperature-programmed reduction (TPR) results, as well as our previous studies, the possible interaction model between dispersed copper and manganese oxide species as well as γ-Al2O3 surface has been proposed. In this model, Cu and Mn ions occupied the octahedral vacant sites of γ-Al2O3, with the capping oxygen on top of the metal ions to keep the charge conservation. For the fresh CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, the -Cu-O-Cu- and -Mn-O-Mn- species were formed on the surface of γ-Al2O3, respectively; but for the fresh CuO-Mn2O3/γ-Al2O3 catalyst, -Cu-O-Mn- species existed on the surface of -Al2O3. After CO pretreatment, -Cu-□-Cu- and -Mn-□-Mn- (□ represents surface oxygen vacancy (SOV)) species would be formed in CO-pretreated CuO/γ-Al2O3 and CO-pretreated Mn2O3/γ-Al2O3 catalysts, respectively; whereas -Cu-□-Mn- species existed in CO-pretreated CuO-Mn2O3/γ-Al2O3. Herein, a new concept, surface synergetic oxygen vacancy (SSOV), which describes the oxygen vacancy formed between the individual Mn and Cu ions, is proposed for CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst. In addition, the role of SSOV has also been approached by NO temperature-programmed desorption (TPD) and in situ FTIR experiments. The FTIR results of competitive adsorption between NO and CO on all the CO-pretreated CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuO-Mn2O3/γ-Al2O3 samples demonstrated that NO molecules mainly were adsorbed on Mn2+ and CO mainly on Cu+ sites. The current study suggests that the properties of the SSOVs in CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst were significantly different to SOVs formed in CO-pretreated CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, and the SSOVs played an important role in NO reduction by CO.