scholarly journals Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2181
Author(s):  
José Vitor C. do Carmo ◽  
Cleanio L. Lima ◽  
Gabriela Mota ◽  
Ariane M. S. Santos ◽  
Ludyane N. Costa ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Pt Nanoparticles ◽  
Catalytic Performance ◽  
Titanate Nanotubes ◽  
Long Term Stability ◽  
Ion Exchange Reaction ◽  
Nox Conversion ◽  
Process Understanding ◽  
Reduction Of Nox ◽  
Sulfur Deposits

Effects of the incorporation of Cr, Ni, Co, Ag, Al, Ni and Pt cations in titanate nanotubes (NTs) were examined on the NOx conversion. The structural and morphological characterizations evidenced that the ion-exchange reaction of Cr, Co, Ni and Al ions with the NTs produced catalysts with metals included in the interlayer regions of the trititanate NTs whereas an assembly of Ag and Pt nanoparticles were either on the nanotubes surface or inner diameters through an impregnation process. Understanding the role of the different metal cations intercalated or supported on the nanotubes, the optimal selective catalytic reduction of NOx by CO reaction (SCR) conditions was investigated by carrying out variations in the reaction temperature, SO2 and H2O poisoning and long-term stability runs. Pt nanoparticles on the NTs exhibited superior activity compared to the Cr, Co and Al intercalated in the nanotubes and even to the Ag and Ni counterparts. Resistance against SO2 poisoning was low on NiNT due to the trititanate phase transformation into TiO2 and also to sulfur deposits on Ni sites. However, the interaction between Pt2+ from PtOx and Ti4+ in the NTs favored the adsorption of both NOx and CO enhancing the catalytic performance.

Investigation of the SCR Catalyst Ce-V/TiO2

2009 ◽  
Vol 610-613 ◽  
pp. 274-280
Author(s):  
Fen Wang ◽  
Xiu Feng Ren ◽  
Jian Feng Zhu ◽  
Hai Bo Yang
Keyword(s):  
Reaction Temperature ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
Selective Reduction ◽  
Catalytic Performance ◽  
Scr Catalyst ◽  
Nox Conversion ◽  
Selective Reduction Of Nox ◽  
Reduction Of Nox ◽  
Catalytic Performances

The Ce-V/TiO2 catalysts with the selective catalytic reduction (SCR) were prepared by method of Sol-gel and insuccation. The phase compositions, microstructures and specific surface area of the catalysts were analyzed by XRD, SEM and BET, respectively. The effect of CeO2 and V2O5 loading and reaction temperature on the catalytic performances of the as-prepared catalysts was investigated by using the selective reduction of NOx with NH3. The results showed all the as-prepared Ce-V/TiO2 catalysts were made up of nanometer grains. Compared to conventional TiO2 catalysts, the as-prepared Ce-V/TiO2 catalysts possessed better catalytic performance, higher adsorbability and larger area of contact with reactant, which is due to large quantity surface micropores. The NOx conversion of SCR over 5wt%Ce-10wt%V/TiO2 catalysts reached 96.2% at the reaction temperature of 500 oC.

scholarly journals Numerical Investigation on the Intraphase and Interphase Mass Transfer Limitations for NH3-SCR over Cu-ZSM-5

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1966
Author(s):  
Shiyong Yu ◽  
Jichao Zhang
Keyword(s):  
Pressure Drop ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Catalytic Performance ◽  
No Oxidation ◽  
Relative Pressure ◽  
Nh3 Scr ◽  
Nox Conversion ◽  
Nh3 Adsorption ◽  
Media Channels

A systematic modeling approach was scrutinized to develop a kinetic model and a novel monolith channel geometry was designed for NH3 selective catalytic reduction (NH3-SCR) over Cu-ZSM-5. The redox characteristic of Cu-based catalysts and the variations of NH3, NOx concentration, and NOx conversion along the axis in porous media channels were studied. The relative pressure drop in different channels, the variations of NH3 and NOx conversion efficiency were analyzed. The model mainly considers NH3 adsorption and desorption, NH3 oxidation, NO oxidation, and NOx reduction. The results showed that the model could accurately predict the NH3-SCR reaction. In addition, it was found that the Cu-based zeolite catalyst had poor low-temperature catalytic performance and good high-temperature activity. Moreover, the catalytic reaction of NH3-SCR was mainly concentrated in the upper part of the reactor. In addition, the hexagonal channel could effectively improve the diffusion rate of gas reactants to the catalyst wall, reduce the pressure drop and improve the catalytic conversion efficiencies of NH3 and NOx.

scholarly journals Effect of the calcination temperature of cerium–zirconium mixed oxides on the structure and catalytic performance of WO3/CeZrO2 monolithic catalyst for selective catalytic reduction of NOx with NH3

RSC Advances ◽  
2017 ◽  
Vol 7 (39) ◽  
pp. 24177-24187 ◽  
Author(s):  
Haidi Xu ◽  
Mengmeng Sun ◽  
Shuang Liu ◽  
Yuanshan Li ◽  
Jianli Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Lewis Acid ◽  
Mixed Oxides ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Reduction Of Nox ◽  
Calcined Temperature

The calcined temperature of the carrier obviously affected SCR activity of catalysts, WO3/Ce0.68Zr0.32O2-500 showed the best low-temperature NH3-SCR activity due to its more Lewis acid sites and stronger redox property.

scholarly journals Catalysis of Organic Pollutants Abatement Based on Pt-Decorated Ag@Cu2O Heterostructures

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2721
Author(s):  
Xiaolong Zhang ◽  
Bingbing Han ◽  
Yaxin Wang ◽  
Yang Liu ◽  
Lei Chen ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Structural Characteristics ◽  
Organic Pollutant ◽  
Pt Nanoparticles ◽  
Catalytic Performance ◽  
Pt Nanoparticle ◽  
Local Surface ◽  
Local Surface Plasmon Resonance ◽  
Cu2o Nanoparticles ◽  
Excellent Catalytic Performance

Pt-decorated Ag@Cu2O heterostructures were successfully synthesized using a simple and convenient method. The Pt nanoparticle density on the Ag@Cu2O can be controlled by changing the concentration of the Pt precursor. The synthesized Ag@Cu2O–Pt nanoparticles exhibited excellent catalytic performance, which was greatly affected by changes in the Ag@Cu2O–Pt structure. To optimize the material’s properties, the synthesized Ag@Cu2O–Pt nanoparticles were used to catalyze toxic pollutants and methyl orange (MO), and nontoxic products were obtained by catalytic reduction. The Pt-decorated Ag@Cu2O nanoparticles showed excellent catalytic activity, which significantly decreased the pollutant concentration when the nanoparticles were used for catalytic reduction. The redistribution of charge transfer is the nanoparticles’ main contribution to the catalytic degradation of an organic pollutant. This Pt-decorated Ag@Cu2O material has unique optical and structural characteristics that make it suitable for photocatalysis, local surface plasmon resonance, and peroxide catalysis.

Novel Fe–Ce–Ti catalyst with remarkable performance for the selective catalytic reduction of NOx by NH3

2016 ◽  
Vol 6 (17) ◽  
pp. 6688-6696 ◽  
Author(s):  
Zhiming Liu ◽  
Yuxian Liu ◽  
Biaohua Chen ◽  
Tianle Zhu ◽  
Lingling Ma
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Redox Cycle ◽  
Reaction Intermediates ◽  
Scr Of No ◽  
Reduction Of Nox

The redox cycle (Ce4+ + Fe2+ ↔ Ce3+ + Fe3+) over the Fe–Ce–Ti catalyst contributes to the activation of NOx and NH3 and thus the formation of reaction intermediates, leading to the high catalytic performance for the NH3-SCR of NOx.

scholarly journals The Enhanced Performance of N-Modified Activated Carbon Promoted with Ce in Selective Catalytic Reduction of NOx with NH3

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1423
Author(s):  
Marwa Saad ◽  
Agnieszka Szymaszek ◽  
Anna Białas ◽  
Bogdan Samojeden ◽  
Monika Motak
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Reduction Mechanism ◽  
Modified Activated Carbon ◽  
Oxidation Reduction ◽  
Reduction Of Nox

The goal of the study was to modify activated carbon (AC) with nitrogen groups and ceria and to test the obtained materials in low temperature selective catalytic reduction of nitrogen oxides. For that purpose, the starting AC was oxidized with HNO3 of various concentrations, modified with urea and doped with 0.5 wt.% of Ce. It was observed that the increased concentration of acid influenced the catalytic activity, since textural and surface chemistry of activated carbon was changed. The most active sample was that modified with 14 M HNO3 and it reached 96% of NO conversion at 300 °C. Additionally, the addition of Ce improved the catalytic performance of modified AC, and NO was reduced according to oxidation–reduction mechanism, characteristic for supported metal oxides. Nevertheless, the samples promoted with Ce emitted significantly higher amount of CO2 comparing to the non-promoted ones.

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