Article

Influence of ferric oxide modification on the properties of copper oxide supported on γ-alumina

Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
Journal of Colloid and Interface Science (Impact Factor: 3.55). 03/2010; 343(2):522-528. DOI: 10.1016/j.jcis.2009.11.050

ABSTRACT X-ray diffraction (XRD), Mössbauer spectroscopy, and temperature-programmed reduction (TPR) were employed to investigate the dispersion and reduction behaviors of the Fe2O3/CuO/γ-Al2O3 system. The results indicated that: (1) the crystalline CuO particle in the CuO/γ-Al2O3 samples was redispersed during impregnating CuO/γ-Al2O3 samples with Fe(NO3)3 solutions; (2) two different dispersion states of surface iron species could be observed, i.e., State I corresponding to the iron(III) species located in the D layer on the surface of γ-Al2O3 and State II corresponding to those in the C layer. The dispersed states of surface iron(III) species were closely related to the iron loading amount; (3) the copper species located in the D layer of alumina surface was easily reduced and the copper species located in the C layer were more stable, which could be due to the influence of the iron(III) species in the different layers; (4) in the NO+CO reaction, the catalytic performances were enhanced due to the Cu–Fe synergism and the main active species in this system should be the surface-dispersed copper oxide species.

Download full-text

Full-text

Available from: Bin Liu, Mar 09, 2015
0 Followers
 · 
70 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The effects of Ag2O-doping on the physicochemical, surface and catalytic properties of FeAlO system with various extents of Fe2O3 loading have been investigated. The dopant concentration was changed between 1.5 and 4.0 mol % Ag2O. Pure and variously doped solids were subjected to heat treatment at 400–800 °C. The techniques employed for characterization of catalysts were TG/DTG, XRD, N2-adsorption at −196 °C and the catalytic decomposition of H2O2 at 25–40 °C. The results obtained revealed that, the investigated catalysts consisted of nanosized γ-Al2O3 phase. The textural properties including SBET, porosity and St were modified by Ag2O-doping. The doping process with Ag-species improves the catalytic activity of FeAlO system. Increasing the precalcination temperature from 400 to 800 °C increases the catalytic activity of 3.5% AgFeAlO with 1.9-fold toward H2O2 decomposition at 30 °C. Furthermore, the maximum increase in the catalytic activity due to doping with 3.5 mol % Ag2O at 30 °C attained about 15.1-fold for the solids calcined at 800 °C.
    01/2011; 02(02). DOI:10.4172/2157-7544.1000108
  • [Show abstract] [Hide abstract]
    ABSTRACT: Supported copper oxide catalysts (CuO/Al2O3, CuO/ZrO2/Al2O3, CuO/ZrO2–Al2O3) were prepared from different procedures and tested in the catalytic reduction of NO with CO to investigate the effect of ZrO2 addition method. The catalysts were characterized by means of ICP, BET, XRD, Raman, H2-TPR, XPS, FTIR of NO or/and CO adsorption. Activity results demonstrated that the addition of ZrO2 could improve catalytic performance, which is dependent on the addition method. The sequence of activity is CuO/ZrO2–Al2O3 > CuO/ZrO2/Al2O3 > CuO/Al2O3. Based on the results of composition and texture, CuO/ZrO2–Al2O3 sample shows more surface zirconia species and larger surface area than CuO/ZrO2/Al2O3. XRD and Raman results suggest amorphous ZrO2 and highly dispersed copper oxide species are mainly present in the ZrO2-added catalysts except for a few CuO crystallites in CuO/ZrO2/Al2O3. Highly dispersed copper oxide species strongly interacting with amorphous zirconia (Cu⋯O⋯Zr species) was observed in H2-TPR and XPS, which was considered as the origin of the enhanced activity. In addition, the adsorption type and configuration of NO was similar over these catalysts. However, CuO/ZrO2–Al2O3 sample shows the greater capacity to activate the adsorbed NO species than CuO/ZrO2/Al2O3.
    Applied Catalysis A General 05/2012; s 423–424:42–51. DOI:10.1016/j.apcata.2012.02.017 · 3.67 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Fe2O3/Al2O3 catalysts (2% Fe) were prepared and characterized by XRD, BET, Raman, and SEM-EDAX. The systems were tested for the catalytic oxidation of phenol solutions (5000 ppm) with H2O2. The effects of reaction temperature, catalyst loading, phenol initial concentration, and H2O2:phenol molar ratio were evaluated. The relatively low oxidant consumption rates favored increased mineralization levels at substoichiometric H2O2 initial concentrations. The stability of the catalytic system was improved by means of a thermal treatment at 900°C, which did not seriously affect the overall reaction performance.
    Industrial & Engineering Chemistry Research 06/2012; 51(26):8979–8984. DOI:10.1021/ie300416n · 2.24 Impact Factor
Show more