Effect of Mg and Zr Modification on the Activity of VOx/Al2O3 Catalysts in the Dehydrogenation of Butanes

2001 ◽  
Vol 203 (1) ◽  
pp. 242-252 ◽  
Author(s):  
M.E Harlin ◽  
V.M Niemi ◽  
A.O.I Krause ◽  
B.M Weckhuysen
Keyword(s):  
Zr Modification

Zr modified SrNbO2N as an active photocatalyst for water oxidation under visible light illumination

2020 ◽  
Vol 7 (14) ◽  
pp. 2629-2636
Author(s):  
Guoan Lin ◽  
Ran Wang ◽  
Tongcheng Cao ◽  
Liangxi Yuan ◽  
Xiaoxiang Xu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Water Oxidation ◽  
Defect Formation ◽  
Light Illumination ◽  
Surface Hydrophilicity ◽  
Visible Light Illumination ◽  
Porous Microstructures ◽  
Zr Modification

Zr modification induces porous microstructures, inhibits defect formation and ameliorates the surface hydrophilicity of SrNbO2N, resulting in good photocatalytic activity.

scholarly journals Production ofC3+Olefins and Propylene from Ethanol by Zr-Modified H-ZSM-5 Zeolite Catalysts

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Megumu Inaba ◽  
Kazuhisa Murata ◽  
Isao Takahara ◽  
Ken-ichiro Inoue
Keyword(s):  
Carbon Deposition ◽  
Aqueous Ethanol ◽  
Zeolite Catalysts ◽  
Ethanol Conversion ◽  
Initial Yield ◽  
Zeolite Support ◽  
Propylene Yield ◽  
Zr Modification ◽  
Catalytic Deactivation

Ethanol conversion to C3+olefins, especially propylene, using Zr-modified H-ZSM-5 catalysts was investigated. Zr-modification to H-ZSM-5 zeolite could improve the initial yield of C3+olefins and propylene and could reduce the initial yield of ethylene. In general, catalysts exhibiting the higher initial yield of propylene showed the steeper decrease in propylene yield as the reaction proceeded. However, Zr-modification to H-ZSM-5 could depress the decrease in propylene yield for aqueous ethanol. As cause of catalytic deactivation, carbon deposition on catalyst and framework collapse of zeolite support can be considered. The addition of water to Zr-modified H-ZSM-5 catalyst could depress carbon deposition in some degree, and, as a result, the decrease in propylene yield could be depressed.

scholarly journals Zr-Modified ZnO for the Selective Oxidation of Cinnamaldehyde to Benzaldehyde

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 716 ◽  
Author(s):  
Pengju Du ◽  
Tongming Su ◽  
Xuan Luo ◽  
Xinling Xie ◽  
Zuzeng Qin ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Selective Oxidation ◽  
Active Sites ◽  
Catalyst Surface ◽  
Precipitation Method ◽  
N2 Adsorption ◽  
X Ray ◽  
Temperature Programmed ◽  
Zr Modification ◽  
Adsorption Desorption

ZnO and Zr-modified ZnO were prepared using a precipitation method and used for the selective oxidation of cinnamaldehyde to benzaldehyde in the present study. The results showed that physicochemical properties of ZnO were significantly affected by the calcination temperature, and calcination of ZnO at 400 °C demonstrated the optimum catalytic activity for the selective oxidation of cinnamaldehyde to benzaldehyde. With 0.01 g ZnO calcined at 400 °C for 2 h as a catalyst, 8.0 g ethanol and 2.0 g cinnamaldehyde reacted at an oxygen pressure of 1.0 MPa and 70 °C for 60 min, resulting in benzaldehyde selectivity of 69.2% and cinnamaldehyde conversion of 16.1%. Zr was the optimal modifier for ZnO: when Zr-modified ZnO was used as the catalyst, benzaldehyde selectivity reached 86.2%, and cinnamaldehyde conversion was 17.6%. The X-ray diffractometer and N2 adsorption–desorption characterization indicated that doping with Zr could reduce the crystallite size of ZnO (101) and increase the specific surface area of the catalyst, which provided more active sites for the reaction. X-ray photoelectron spectrometer results showed that Zr-doping could exchange the electrons with ZnO and reduce the electron density in the outer layer of Zn, which would further affect benzaldehyde selectivity. The results of CO2 temperature-programmed desorption showed that Zr-modification enhanced the alkalinity of the catalyst surface, which caused the Zr–ZnO catalyst to exhibit higher catalytic activity.

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