Activity of yFe-10Cu/H-Sep and xCu/H-Sep for the Selective Catalytic Reduction of NO with Propylene

2012 ◽  
Vol 518-523 ◽  
pp. 281-284
Author(s):  
Qing Ye ◽  
Hai Ping Wang ◽  
Hai Xia Zhao ◽  
Shui Yuan Cheng ◽  
Tian Fang Kang
Keyword(s):  
Catalytic Reduction ◽  
Catalytic Performance ◽  
High Dispersion ◽  
High Catalytic Activity ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Promotional Effect ◽  
Scr Of No ◽  
Metal Support Interaction ◽  
Metal Support

Cu supported on acid-treated sepiolite catalysts (xCu/H-Sep, x = 0  20.0 wt%) or Cu-Fe mixed supported on acid-treated sepiolite catalysts (yFe-10Cu/H-Sep, y = 0  20.0 wt%) were prepared by the incipient wetness impregnation method. The xCu/H-Sep and yFe-10Cu/H-Sep catalysts were characterized by means of XRD, BET, XRF, XPS, and H2-TPR techniques, and their catalytic activities were evaluated for the SCR of NO with propylene. XPS and XRD results indicate that there was the co-presence of Cu+-Cu2+ and Fe2+-Fe3+ over the surfaces of yFe-10Cu/H-Sep catalysts, and there was a strong interaction between Cu, Fe and sepiolite. High promotional effect of iron additive on the catalytic performance of Cu/H-Sep catalyst were found in C3H6-SCR of NO reaction. The highest activity of 65% NO conversion was obtained over 15Fe-10Cu/H-Sep catalyst at 280 oC under the condition of 1000 ppm NO, 1000 ppm C3H6, and 5% O2. The high catalytic activity of 15Fe-10Cu/H-Sep catalyst for NO reduction was due to its high reducibility to activate C3H6 to selectively reduce NO in the presence of excess O2. The high dispersion of copper oxides and strong metal-support interaction over 15Fe-10Cu/H-Sep catalyst also improve its catalytic performance.

Enhanced Activity of Fe-Doped Cu/H-Sep for the SCR of NO with Propylene in the Presence of Oxygen

2014 ◽  
Vol 700 ◽  
pp. 261-264
Author(s):  
Yang Li ◽  
Qing Ye ◽  
Zhi Hao Zhang ◽  
Yun Fang Qi ◽  
Li Sha Liu
Keyword(s):  
Catalytic Activity ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Copper Species ◽  
Catalytic Activities ◽  
Support Interaction ◽  
Scr Of No ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Incipient Wetness

Cu/H-Sep and Cu-Fe/H-Sep samples were prepared by the incipient wetness impregnation method. These catalysts were characterized by means of XRF, XRD, BET, XPS, and H2-TPR techniques, and their catalytic activities were performed by the SCR of NO with propylene. The results show that the Cu-Fe/H-Sep catalyst exhibited the best performance in the C3H6-SCR of NO. After investigation by H2-TPR, XRD and XPS, the result showed that the higher reducibility, more amount of isolated Cu2+, higher dispersion of copper species, and stronger metal-support interaction were responsible for the excellent catalytic activity of Cu-Fe/H-Sep.

scholarly journals Defect-Rich Nickel Nanoparticles Supported on SiC Derived from Silica Fume with Enhanced Catalytic Performance for CO Methanation

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 295 ◽  
Author(s):  
Qi Song ◽  
Xingwu Zhai ◽  
Feng Yu ◽  
Jiangbing Li ◽  
Xin Ren ◽  
...  
Keyword(s):  
Silica Fume ◽  
Density Functional ◽  
Co Adsorption ◽  
Space Velocity ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Impregnation Method ◽  
Ni Nanoparticles ◽  
Metal Support Interaction ◽  
Metal Support

With the increased demands of environmental protection, recycling/utilization of industrial byproducts has attracted much attention from both industry and academic communities. In this work, silicon carbide (SiC) was successfully synthesized from industrial waste silica fume (SF) during metallic silicon production. Following this, Ni nanoparticles with many defects were supported on the as-obtained SiC by conventional impregnation method. The results showed that defect-rich Ni nanoparticles were dispersed onto the surface of SiC. The as-obtained Ni/SF-SiC exhibited an enhanced metal-support interaction between Ni and SiC. Furthermore, the density functional theory (DFT) calculations showed that the H2 and CO adsorption energy on Ni vacancy (VNi) sites of Ni/SF-SiC were 1.84 and 4.88 eV, respectively. Finally, the Ni/SF-SiC performed high catalytic activity with CO conversion of 99.1% and CH4 selectivity of 85.7% at 350 °C, 0.1 MPa and a gas hourly space velocity (GHSV) of 18,000 mL·g−1·h−1. Moreover, Ni/SF-SiC processed good catalytic stability in the 50 h continuous reaction.

Cu-Supported on Sodium-Treated Sepiolite for Selective Catalytic Reduction of NO by Propylene

2015 ◽  
Vol 1088 ◽  
pp. 569-572
Author(s):  
Zhi Hao Zhang ◽  
Yang Li ◽  
Yun Fang Qi ◽  
Qing Ye ◽  
Shu Lan Ji ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
High Performance ◽  
Catalytic Reduction ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Redox Species ◽  
Reduction Of No ◽  
Catalytic Activities ◽  
Scr Of No ◽  
Activity Center

Cu/Na-Sep samples were prepared by the incipient wetness impregnation method. These catalysts were characterized by means of XRF, XRD, and XPS techniques, and their catalytic activities were performed by the SCR of NO with propylene. The results show that the Cu/Na-Sep catalyst exhibited the high performance in the C3H6-SCR of NO. After investigation by XRD and XPS, the result showed that there are Cu2+/Cu+redox species as a reaction activity center over Cu/Na-Sep.

scholarly journals Effect of Preparation Mode on the Properties of Mn-Na-W/SiO2 Catalysts for Oxidative Coupling of Methane: Conventional Methods vs. POSS Nanotechnology

2016 ◽  
Vol 18 (2) ◽  
pp. 93 ◽  
Author(s):  
I.Z. Ismagilov ◽  
E.V. Matus ◽  
V.V. Kuznetsov ◽  
M.A. Kerzhentsev ◽  
S.A. Yashnik ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Oxidative Coupling Of Methane ◽  
Molar Ratio ◽  
High Dispersion ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Preparation Mode ◽  
Slurry Method ◽  
Conventional Methods

<p>Reflectance spectroscopic methods the electronic, redox and structural properties of Mn-Na-W/SiO<sub>2</sub> catalysts prepared by the incipient wetness impregnation method and mixture slurry method were studied in detail. Since POSS nanotechnology (POSS = polyhedral oligomeric silsesquioxanes) has attracted attention as tooling for synthesis of catalysts with novel properties and functionalities, we expanded this method for the preparation of Mn-Na-W/SiO<sub>2</sub> catalyst. The physicochemical and catalytic properties of Mn-Na-W/SiO<sub>2</sub> catalysts prepared by conventional methods and POSS nanotechnology were examined comparatively. In all studied Mn-Na-W/SiO<sub>2</sub> catalysts both individual oxides (MnO<sub>x</sub>, WO<sub>3</sub>) and bimetal oxide phases (Na<sub>2</sub>WO<sub>4</sub>, MnWO<sub>4</sub>) are found in addition to oxide particles of high dispersion. The UV-Vis Diffuse Reflectance indicates that Na<sup>+</sup> cations facilitates stabilization of octahedrally coordinated Mn<sup>3+</sup><sub>Oh</sub> cations in the isolated state, while Mn<sup>3+</sup><sub>Oh</sub> promote the disordering of W<sup>6+</sup> cations in the supported system. The Mn-Na-W/SiO<sub>2</sub> prepared using metal-POSS precursors marks out presence of unglobular SiO<sub>2</sub> particles, higher dispersion of MnO<sub>x</sub> and MnWO<sub>4</sub> particles and more easily reducible metal-oxide species. The catalysts prepared by incipient impregnation method and mixture slurry method have practically similar catalytic performance while the catalyst prepared by POSS nanotechnology method shows lower activity and selectivity. At 800‒850 °C the increase of C<sub>2</sub> hydrocarbons yield from 4 to 15% and the rise of molar ratio С<sub>2</sub>Н<sub>4</sub>/C<sub>2</sub>H<sub>6</sub> from 0.2 to 1 are observed when impregnation or mixture slurry method are used for catalyst preparation instead of POSS nanotechnology method.</p>

scholarly journals Promotional Effect of Manganese on Selective Catalytic Reduction of NO by CO in the Presence of Excess O2 over M@La–Fe/AC (M = Mn, Ce) Catalyst

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1322
Author(s):  
Fatemeh Gholami ◽  
Zahra Gholami ◽  
Martin Tomas ◽  
Veronika Vavrunkova ◽  
Somayeh Mirzaei ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Oxygen Vacancies ◽  
Catalytic Reduction ◽  
Catalyst Activity ◽  
Double Exchange ◽  
Catalytic Performance ◽  
Redox Equilibrium ◽  
Metal Site ◽  
Promotional Effect ◽  
Scr Of No

The catalytic performance of a series of La-Fe/AC catalysts was studied for the selective catalytic reduction (SCR) of NO by CO. With the increase in La content, the Fe2+/Fe3+ ratio and amount of surface oxygen vacancies (SOV) in the catalysts increased; thus the catalytic activity improved. Incorporating the promoters to La3-Fe1/active carbon (AC) catalyst could affect the catalyst activity by changing the electronic structure. The increase in Fe2+/Fe3+ ratio after the promoter addition is possibly due to the extra synergistic interaction of M (Mn and Ce) and Fe through the redox equilibrium of M3+ + Fe3+ ↔ M4+ + Fe2+. This phenomenon could have improved the redox cycle, enhanced the SOV formation, facilitated NO decomposition, and accelerated the CO-SCR process. The presence of O2 enhanced the formation of the C(O) complex and improved the activation of the metal site. Mn@La3-Fe1/AC catalyst revealed an excellent NO conversion of 93.8% at 400 °C in the presence of 10% oxygen. The high catalytic performance of MnOx and double exchange behavior of Mn3+ and Mn4+ can increase the number of SOV and improve the catalytic redox properties.

scholarly journals Green Synthesis of a Cu/SiO2 Catalyst for Efficient H2-SCR of NO

2019 ◽  
Vol 9 (19) ◽  
pp. 4075 ◽  
Author(s):  
Esteban Gioria ◽  
F. Marchesini ◽  
Analía Soldati ◽  
Antonella Giorello ◽  
Jose Hueso ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Aqueous Suspension ◽  
Colloidal Suspensions ◽  
Catalytic Performance ◽  
Sodium Hypophosphite ◽  
Stabilizing Agents ◽  
Green Approach ◽  
Water As Solvent ◽  
Metal Support Interaction ◽  
Metal Support

In this work, the synthesis of Cu/SiO2 catalysts starting from pre-formed copper nanoparticle (CuNP) colloidal suspensions was carried out. Two different protocols for the CuNP synthesis were tested: (i) a green approach using water as solvent and ascorbic acid as reducer and stabilizing agent, and (ii) a second solvothermal method involving the use of diethylene glycol as solvent, sodium hypophosphite (NaH2PO2) as reducer, and polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) as stabilizing agents. In addition, and for the sake of comparison, a third catalyst was prepared by solid state conventional grinding of CuO with SiO2. The catalysts were tested in the environmentally relevant catalytic reduction of NOX with H2, in a temperature range from 300 to 500 °C. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR) cycles, Raman spectroscopy, and N2 adsorption for specific surface BET measurements. From these techniques CuO and Cu(0) species were detected depending on the synthesis protocol. CuNP size and size distribution in the colloid suspensions were determined by transmission electronic microscopy (TEM). The catalyst prepared from the aqueous suspension (CuAsc/SiO2) exhibited higher NO conversion (100%) and selectivity (85%) toward N2 at the lower reaction evaluated temperature (300 °C). The CuCTAB/SiO2 catalyst obtained by the solvothermal approach showed activity at high reaction temperature (400 °C) preferentially. The metal–support mechanical mixture exhibited a negligible response at low temperature and low conversion (68%) and selectivity (88%) at 500 °C. Nanoparticle size and distribution on the support, together with the metal–support interaction, were postulated as the most plausible parameters governing the catalytic performance of the different Cu/SiO2 materials.

scholarly journals Operando DRIFTS-MS Study of WGS and rWGS Reaction on Biochar-Based Pt Catalysts: The Promotional Effect of Na

2018 ◽  
Vol 4 (3) ◽  
pp. 47 ◽  
Author(s):  
José Santos ◽  
Luis Bobadilla ◽  
Miguel Centeno ◽  
José Odriozola
Keyword(s):  
Inductively Coupled Plasma ◽  
Active Sites ◽  
Catalytic Performance ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Pt Catalysts ◽  
Inductively Coupled ◽  
Promotional Effect ◽  
Rwgs Reaction ◽  
Diffuse Reflectance Infrared

Biochar-based Pt catalysts, unpromoted and Na-promoted, were prepared by an incipient wetness impregnation method and characterised by Inductively coupled plasma mass spoectrometry (ICP-MS) analysis, X-ray diffraction, N2 adsorption and transmission, and scanning electron microscopy. It was demonstrated that a sodium promoter modifies the acid-base properties of the support, altering the Pt-support interaction. An operando Diffuse reflectance infrared fourier transform spectroscopy-mass spectrometry (DRIFTS-MS) study was performed to gain insights into the reaction pathways and the mechanism of the Water-Gass-Shift (WGS) and the Reverse Water-Gass-Shift (rWGS) reactions. It was demonstrated that the addition of Na enhances the catalytic performance due to the changes induced by the alkali in the electronic structure of the Pt active sites. This effect favours the activation of H2O molecules during the WGS reaction and the dissociation of CO2 during the rWGS reaction, although it may also favour the consecutive CO methanation pathway.

Direct Dehydrogenation of n-Butane Over Pt/Sn/Zn/γ-Al2O3 Nano-Catalyst: Effect of Zn Content

2015 ◽  
Vol 15 (10) ◽  
pp. 8318-8323
Author(s):  
Hyun Seo ◽  
Jong Kwon Lee ◽  
Ung Gi Hong ◽  
Gle Park ◽  
Yeonshick Yoo ◽  
...  
Keyword(s):  
Surface Area ◽  
Zinc Content ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Support Interaction ◽  
Nano Catalyst ◽  
Metal Support Interaction ◽  
Zn Content ◽  
Metal Support ◽  
Nano Catalysts

A series of Pt/Sn/XZn/γ-Al2O3 nano-catalysts with different Zn content (X = 0, 0.25, 0.5, 0.75, and 1.0 wt%) were prepared by a sequential impregnation method. They were applied to the direct dehydrogenation of n-butane to n-butene and 1,3-butadiene. The effect of zinc content of Pt/Sn/XZn/γ-Al2O3 nano-catalysts on their physicochemical properties and catalytic activities in the direct dehydrogenation of n-butane was investigated. The catalytic performance of Pt/Sn/XZn/γ-Al2O3 nano-catalysts strongly depended on zinc content. Among the catalysts tested, Pt/Sn/0.5Zn/γ-Al2O3 nano-catalyst showed the best catalytic performance in terms of yield for total dehydrogenation products (TDP, n-butene and 1,3-butadiene). TPR (temperature-programmed reduction) and H2-chemisorption experiments were carried out to measure metal-support interaction and Pt surface area of the catalysts. Experimental results revealed that metal-support interaction and Pt surface area of the catalysts were closely related to the catalytic performance. Yield for TDP increased with increasing metal-support interaction and Pt surface area of the catalysts.

scholarly journals Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for SCR of NO with NH3

2017 ◽  
Vol 19 (1) ◽  
pp. 160-166 ◽  
Keyword(s):  
Active Sites ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Spectra Analysis ◽  
Xps Spectra ◽  
Scr Of No ◽  
Morphology And Structure ◽  
Method Effects ◽  
Xrd Patterns

<p>V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts were fabricated by a simple impregnation method. Effects of V<sub>2</sub>O<sub>5</sub> and WO<sub>3</sub> loadings on the catalytic performance of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2</sub> catalyst for selective catalytic reduction (SCR) of NO with NH<sub>3</sub> were investigated. Morphology and structure of the V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts were characterised by XRD, SEM, XPS, and N<sub>2</sub> adsorption techniques. The XRD patterns of the V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalyst are indexed to anatase-TiO<sub>2</sub>. XPS spectra analysis confirms that V, Ti, W and O species exist on the surface of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalyst. V<sub>2</sub>O<sub>5</sub> species are the main active sites in the process of SCR reaction. Increasing V<sub>2</sub>O<sub>5</sub> loading in the V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts can improve their catalytic performance. Exceeding 2 wt%, the catalytic performance of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalyst begins to decline because high V<sub>2</sub>O<sub>5</sub> loading on TiO<sub>2</sub> speeds up the growth of anatase grains, which leads to the loss of catalytic activity. Appropriate WO<sub>3</sub> species can significantly improve the catalytic performance of V<sub>2</sub>O<sub>5</sub>-WO<sub>3</sub>/TiO<sub>2 </sub>catalysts. However, as the WO<sub>3 </sub>loadings reaches 6 wt%, NO conversion decreases instead.</p>

scholarly journals The promotional role of Ce in Cu/ZSM-5 and in situ surface reaction for selective catalytic reduction of NOx with NH3

RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 90235-90244 ◽  
Author(s):  
Shuangshuang Lai ◽  
Dongmei Meng ◽  
Wangcheng Zhan ◽  
Yun Guo ◽  
Yanglong Guo ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Surface Reaction ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Reduction Of No ◽  
Reduction Of Nox

Ce doped Cu/ZSM-5 catalysts were prepared by the incipient-wetness-impregnation method, and the effect of Ce doping on the structure and the catalytic performance was investigated in detail for the selective catalytic reduction of NO with NH3

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