Mechanism and Performance of the SCR of NO with NH3 over Sulfated Sintered Ore Catalyst

A sulfated sintered ore catalyst (SSOC) was prepared to improve the denitration performance of the sintered ore catalyst (SOC). The catalysts were characterized by X-ray Fluorescence Spectrometry (XRF), Brunauer–Emmett–Teller (BET) analyzer, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared spectroscopy (DRIFTS) to understand the NH3-selective catalytic reduction (SCR) reaction mechanism. Moreover, the denitration performance and stability of SSOC were also investigated. The experimental results indicated that there were more Brønsted acid sites at the surface of SSOC after the treatment by sulfuric acid, which lead to the enhancement of the adsorption capacity of NH3 and NO. Meanwhile, Lewis acid sites were also observed at the SSOC surface. The reaction between −NH2, NH 4 + and NO (E-R mechanism) and the reaction of the coordinated ammonia with the adsorbed NO2 (L-H mechanism) were attributed to NOx reduction. The maximum denitration efficiency over the SSOC, which was about 92%, occurred at 300 °C, with a 1.0 NH3/NO ratio, and 5000 h−1 gas hourly space velocity (GHSV).

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Comparision on the Low-Temperature NH3-SCR Performance of γ-Fe2O3 Catalysts Prepared by Two Different Methods

Catalysts ◽

10.3390/catal9121018 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1018

Author(s):

Naveed Husnain ◽

Enlu Wang ◽

Shagufta Fareed ◽

Muhammad Tuoqeer Anwar

Keyword(s):

Photoelectron Spectroscopy ◽

Catalytic Reduction ◽

Acid Sites ◽

High Concentration ◽

X Ray ◽

Nh3 Scr ◽

Transmission Electron ◽

Temperature Programmed ◽

Diffuse Reflectance Infrared

Maghemite (γ-Fe2O3) catalysts were prepared by two different methods, and their activities and selectivities for selective catalytic reduction of NO with NH3 were investigated. The methods of X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) were used to characterize the catalysts. The resulted demonstrated that the γ-Fe2O3 nanoparticles prepared by the facile method (γ-Fe2O3–FM) not only exhibited better NH3-SCR activity and selectivity than the catalyst prepared by the coprecipitation method but also showed improved SO2 tolerance. This superior NH3-SCR performance was credited to the existence of the larger surface area, better pore structure, a high concentration of lattice oxygen and surface-adsorbed oxygen, good reducibility, a lot of acid sites, lower activation energy, adsorption of the reactants, and the existence of unstable nitrates on the surface of the γ-Fe2O3–FM.

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Nanosized V-Ce Oxides Supported on TiO2 as a Superior Catalyst for the Selective Catalytic Reduction of NO

Catalysts ◽

10.3390/catal10020202 ◽

2020 ◽

Vol 10 (2) ◽

pp. 202

Author(s):

Long Lu ◽

Xueman Wang ◽

Chunhua Hu ◽

Ying Liu ◽

Xiongbo Chen ◽

...

Keyword(s):

Low Temperature ◽

Selective Catalytic Reduction ◽

Photoelectron Spectroscopy ◽

Catalytic Reduction ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Redox Capacity ◽

Scr Of No ◽

Temperature Programmed

Nanosized V-Ce oxides supported on TiO2 (VCT) were prepared and utilized in the low-temperature selective catalytic reduction (SCR) of NO with NH3. Compared with the other V-Ce oxides-based catalysts supported on Al2O3, ZrO2, and ZSM-5, VCT showed the best SCR activity in a low-temperature range. The NOx conversion of 90% could be achieved at 220 °C. Characterizations including X-ray diffraction (XRD), scanning election micrograph (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption with NH3 (NH3-TPD), and temperature-programmed reduction with H2 (H2-TPR) showed that V1.05Ce1/TiO2 exhibited a good dispersion of V2O5, enrichment of surface Ce3+ and chemical-absorbed oxygen, and excellent redox capacity and acidity, which resulted in the best SCR performance at low temperature.

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Preparation, Characterization, and Performance Analysis of S-Doped Bi2MoO6 Nanosheets

Nanomaterials ◽

10.3390/nano9091341 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1341 ◽

Cited By ~ 1

Author(s):

Ruiqi Wang ◽

Duanyang Li ◽

Hailong Wang ◽

Chenglun Liu ◽

Longjun Xu

Keyword(s):

Photoelectron Spectroscopy ◽

Degradation Rate ◽

X Ray Diffraction ◽

Photo Degradation ◽

X Ray ◽

Transmission Electron ◽

Ft Ir ◽

And Performance ◽

Adsorption Desorption ◽

Excellent Stability

S-doped Bi2MoO6 nanosheets were successfully synthesized by a simple hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), elemental mapping spectroscopy, photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectra (UV-vis DRS). The photo-electrochemical performance of the samples was investigated via an electrochemical workstation. The S-doped Bi2MoO6 nanosheets exhibited enhanced photocatalytic activity under visible light irradiation. The photo-degradation rate of Rhodamine B (RhB) by S-doped Bi2MoO6 (1 wt%) reached 97% after 60 min, which was higher than that of the pure Bi2MoO6 and other S-doped products. The degradation rate of the recovered S-doped Bi2MoO6 (1 wt%) was still nearly 90% in the third cycle, indicating an excellent stability of the catalyst. The radical-capture experiments confirmed that superoxide radicals (·O2−) and holes (h+) were the main active substances in the photocatalytic degradation of RhB by S-doped Bi2MoO6.

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Effect of cerium content on textural and hydrodesulfurization performance for dibenzothiophene over a bulk Ni2P catalyst

Progress in Reaction Kinetics and Mechanism ◽

10.1177/1468678319830798 ◽

2019 ◽

Vol 44 (1) ◽

pp. 37-44 ◽

Cited By ~ 1

Author(s):

Yunwu Yu ◽

Lianjie Liang ◽

Changwei Xu ◽

Yubo Dai ◽

Wenhao Pan ◽

...

Keyword(s):

Crystallite Size ◽

Photoelectron Spectroscopy ◽

Space Velocity ◽

X Ray Diffraction ◽

Reaction Conditions ◽

X Ray ◽

Weight Hourly Space Velocity ◽

Cerium Content ◽

Adsorption Desorption ◽

Hydrodesulfurization Activity

A series of ceria promoted Ni2P catalysts were prepared and evaluated in dibenzothiophene hydrodesulfurization steam. These catalysts were characterized by X-ray diffraction, N2 adsorption–desorption, CO chemisorptions, and X-ray photoelectron spectroscopy. The results showed that the addition of ceria into the bulk Ni2P catalyst was conducive to the formation of the Ni2P phase and contributed to a higher surface area, leading to a better dispersion and smaller crystallite size of Ni2P particles. The CexNi2P catalysts showed higher dibenzothiophene hydrodesulfurization activity than Ni2P catalyst and the Ce0.09Ni2P catalyst showed the highest dibenzothiophene hydrodesulfurization activity. The Ce0.09Ni2P catalyst showed a dibenzothiophene hydrodesulfurization conversion of 94.5% at the reaction conditions of 320°C, 4.0 MPa, a H2/oil ratio of 500 (V/V), and a weight hourly space velocity of 8.0 h−1. The dibenzothiophene was mainly transformed through desulfurization pathway.

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CO2 Methanation of Biogas over 20 wt% Ni-Mg-Al Catalyst: on the Effect of N2, CH4, and O2 on CO2 Conversion Rate

Catalysts ◽

10.3390/catal10101201 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1201

Author(s):

Danbee Han ◽

Yunji Kim ◽

Hyunseung Byun ◽

Wonjun Cho ◽

Youngsoon Baek

Keyword(s):

Reaction Temperature ◽

Photoelectron Spectroscopy ◽

Conversion Rate ◽

Space Velocity ◽

Molar Ratio ◽

Co2 Conversion ◽

X Ray Diffraction ◽

Co2 Methanation ◽

X Ray ◽

Ch4 Production

Biogas contains more than 40% CO2 that can be removed to produce high quality CH4. Recently, CH4 production from CO2 methanation has been reported in several studies. In this study, CO2 methanation of biogas was performed over a 20 wt% Ni-Mg-Al catalyst, and the effects of CO2 conversion rate and CH4 selectivity were investigated as a function of CH4, O2, H2O, and N2 compositions of the biogas. At a gas hourly space velocity (GHSV) of 30,000 h−1, the CO2 conversion rate was ~79.3% with a CH4 selectivity of 95%. In addition, the effects of the reaction temperature (200–450 °C), GHSV (21,000–50,000 h−1), and H2/CO2 molar ratio (3–5) on the CO2 conversion rate and CH4 selectivity over the 20 wt% Ni-Mg-Al catalyst were evaluated. The characteristics of the catalyst were analyzed using Brunauer–Emmett–Teller surface area analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The catalyst was stable for approximately 200 h at a GHSV of 30,000 h−1 and a reaction temperature of 350 °C. CO2 conversion and CH4 selectivity were maintained at 75% and 93%, respectively, and the catalyst was therefore concluded to exhibit stable activity.

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RISING beamline (BL28XU) for rechargeable battery analysis

Journal of Synchrotron Radiation ◽

10.1107/s1600577513025733 ◽

2013 ◽

Vol 21 (1) ◽

pp. 268-272 ◽

Cited By ~ 15

Author(s):

H. Tanida ◽

K. Fukuda ◽

H. Murayama ◽

Y. Orikasa ◽

H. Arai ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Rechargeable Batteries ◽

Time Range ◽

Rechargeable Battery ◽

X Ray Diffraction ◽

Battery Charging ◽

X Ray ◽

And Performance ◽

X Ray Absorption

The newly installed BL28XU beamline at SPring-8 is dedicated toin situstructural and electronic analysis of rechargeable batteries. It supports the time range (1 ms to 100 s) and spatial range (1 µm to 1 mm) needed for battery analysis. Electrochemical apparatus for battery charging and discharging are available in experimental hutches and in a preparation room. Battery analysis can be carried out efficiently and effectively using X-ray diffraction, X-ray absorption fine-structure analysis and hard X-ray photoelectron spectroscopy. Here, the design and performance of the beamline are described, and preliminary results are presented.

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Effect of Ce-modified Fe/ZSM-5 zeolite for selective catalytic reduction of NOx by ammonia

E3S Web of Conferences ◽

10.1051/e3sconf/202021803032 ◽

2020 ◽

Vol 218 ◽

pp. 03032

Author(s):

Chenxi Li ◽

Fanwei Meng ◽

Qing Ye

Keyword(s):

Selective Catalytic Reduction ◽

Photoelectron Spectroscopy ◽

Catalytic Reduction ◽

Catalytic Performance ◽

Acid Sites ◽

Impregnation Method ◽

Adsorption Ability ◽

In Situ Drifts ◽

X Ray

A series of xCe-Fe/ZSM-5 (x = 0, 0.25, 0.5 wt%) samples were prepared by the impregnation method, and the catalytic activity was evaluated by the selective catalytic reduction of NOx with ammonia (NH3-SCR). The physicochemical properties of prepared samples were characterized by various techniques such as X-ray diffraction (XRD), Brunner-Emmet-Teller (BET) measurement, hydrogen temperatureprogrammed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), ammonia temperatureprogrammed desorption (NH3-TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). XRD and BET results demonstrated that Ce and Fe species were uniform dispersed on the surface of the ZSM-5 zeolite and the micropore structure of ZSM-5 was still maintained. H2-TPR analysis indicated that the doping of Ce created more isolated Ce4+ and Fe3+ on the surface of catalysts, and the abundant Ce4+ and Fe3+ could enhance the reduction ability of catalysts. XPS analysis suggested that the doping of Ce could generate more oxygen vacancies, thereby increasing the number of chemisorption oxygen. According to the in-situ DRIFTS and NH3-TPD results, Ce species provided more acidic sites, which is beneficial to the NH3 adsorption ability of ZSM-5 zeolite. Additionally, the abundant chemisorption oxygen, medium and strong Brønsted acid sites, excellent NH3 adsorption ability and outstanding reduction property are beneficial to the NH3-SCR reaction. Among all prepared samples, the 0.25Ce-Fe/ZSM-5 sample possessed the widest reaction temperature window and the best catalytic performance (NO conversion over 98% at 350-450 °C), which was associated with the abundant acid sites and remarkable adsorption ability of NH3, outstanding redox ability and abundant chemisorption oxygen after the doping of Ce.

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Trends in the thermal stability of two-dimensional covalent organic frameworks

Faraday Discussions ◽

10.1039/d0fd00054j ◽

2021 ◽

Cited By ~ 2

Author(s):

Austin M. Evans ◽

Matthew R. Ryder ◽

Woojung Ji ◽

Michael J. Strauss ◽

Amanda R. Corcos ◽

...

Keyword(s):

Thermal Stability ◽

Density Functional ◽

Variable Temperature ◽

Covalent Organic Frameworks ◽

X Ray Diffraction ◽

Functional Theory ◽

X Ray ◽

Diffuse Reflectance Infrared Spectroscopy ◽

Diffuse Reflectance Infrared ◽

Thermal Stability Of

Here, we study the thermal stability of ten 2D covalent organic frameworks using a combination of variable-temperature X-ray diffraction, thermogravimetric analysis, diffuse reflectance infrared spectroscopy, and density-functional theory.

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Applicability of V2O5-WO3/TiO2 Catalysts for the SCR Denitrification of Alumina Calcining Flue Gas

Catalysts ◽

10.3390/catal9030220 ◽

2019 ◽

Vol 9 (3) ◽

pp. 220 ◽

Cited By ~ 7

Author(s):

Ruliang Ning ◽

Li Chen ◽

Erwei Li ◽

Xiaolong Liu ◽

Tingyu Zhu

Keyword(s):

Flue Gas ◽

Photoelectron Spectroscopy ◽

Catalytic Performance ◽

Inhibitory Effect ◽

Impregnation Method ◽

X Ray Diffraction ◽

X Ray ◽

So2 Resistance ◽

Temperature Programmed ◽

Diffuse Reflectance Infrared

V2O5-WO3/TiO2 catalysts with different V2O5 and WO3 loadings were prepared by the impregnation method. H2O and SO2 resistance of the catalysts under high H2O concentration (30 vol.%) was studied. Influence of various basic metal oxides, such as Al2O3, CaO, Na2O, and K2O on the catalytic performance was studied and compared. It is revealed that the inhibitory effect is in the sequence of K > Na > Ca > Al, which is consistent with their alkalinity. X-ray diffraction (XRD), N2 physisorption (BET), temperature-programmed desorption of NH3 (NH3-TPD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were carried out, and the results were well-correlated with the catalytic studies.

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Effect of La Addition on Ru/Al2O3 Catalyst for Selective CO Oxidation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.347-353.3616 ◽

2011 ◽

Vol 347-353 ◽

pp. 3616-3620 ◽

Cited By ~ 1

Author(s):

Xi Rong Chen ◽

Zao Ming Chen ◽

Wei Ming Lin

Keyword(s):

Co Oxidation ◽

Photoelectron Spectroscopy ◽

Impregnation Method ◽

X Ray Diffraction ◽

X Ray ◽

Selective Co Oxidation ◽

La Addition ◽

Temperature Programmed ◽

And Performance ◽

Ru Species

Ru/Al2O3 catalysts with various La2O3 contents were synthesized by impregnation method. The catalysts were tested for selective CO oxidation and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy with energy-dispersive spectroscopy, and H2 temperature-programmed reduction. The effects of La addition into Ru/Al2O3 catalysts on structure and performance were investigated. Results show that higher CO conversions (>99%) and CO2 selectivity are obtained at 110–170 °C on RuLa/Al2O3. La doping promotes the dispersion of Ru species, thereby enhancing catalytic activity. The analysis reveals that the modification of La2O3 is favorable for the formation of active Ru species with good dispersion and enhanced selective CO oxidation.

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