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

2011 ◽  
Vol 347-353 ◽  
pp. 3616-3620 ◽  
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.

Pd-Only Catalyst Modified by BaO with Co- Precipitation and Impregnation Methods towards the Methanol Fuel Emission Control

2012 ◽  
Vol 581-582 ◽  
pp. 313-316
Author(s):  
Xue Qiao Zhang ◽  
Zhi Xiang Ye ◽  
Cheng Hua Xu ◽  
Ming Zhao ◽  
Yao Qiang Chen
Keyword(s):  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Palladium Catalysts ◽  
Active Species ◽  
Precipitation Method ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Co Precipitation

Barium oxide was introduced to modify Palladium catalysts supported on CeO2–ZrO2-La2O3-Al2O3 (CZLA) by impregnation and co-precipitation. methods. Various techniques, including X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS), were employed to characterize the physicochemical properties of BaO-modified Pd-only catalyst. Catalytic activity for methanol, CO, C3H8 and NO conversions showed that BaO-modified catalyst prepared by impregnation method exhibited the best performance for methanol, C3H8 and NO removals, while the catalyst prepared by co-precipitation method was in favor of CO oxidation. Combined with the results of XRD, H2-TPR and XPS, it is concluded that the co-existence of PdO and Pd-O-Ce active species by impregnation played an important role in the methanol, C3H8 and NO removals, while the higher dispersion of palladium and improved reducibility were mostly favorable to the CO oxidation. The conversion of NO was co-effected by tow active species and the formation of Ba2AlLaO5 mixed oxide.

A Temperature-Programmed-Reduction Study on La1−xSrxCrO3 and Surface-Ruthenium-Modified La1−xSrxCrO3

2006 ◽  
Vol 4 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Aiyu Yan ◽  
Bin Liu ◽  
Baofeng Tu ◽  
Yonglai Dong ◽  
Mojie Cheng ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Perovskite Oxides ◽  
Reduction Peak ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Oxides ◽  
Temperature Programmed ◽  
Ru Species ◽  
A Site

A series of La1−xSrxCrO3(0⩽x⩽0.3) composite oxides were prepared by a modified citric method. These perovskite oxides were further modified with Ru through impregnation. X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and temperature-programmed-reduction (TPR) techniques were adopted to investigate the properties of both the as-prepared perovskite oxides and the surface-Ru-modified La1−xSrxCrO3 samples. XPS results indicated the existence of Cr6+ ions in the fresh samples and transformed to Cr3+ after reduction. The hydrogen consumed by these perovskite oxides during TPR increased with the Sr doping, which was more than twice of the theoretical value according to Kröger-Vink notation. The reduction temperature of Cr ions of Ru∕La1−xSrxCrO3 significantly decreased with an increase of the Ru loading. A small reduction peak at ∼540°C, which was not shifted by increasing Ru loadings, was observed and could be ascribed to the reduction of trace chromate phases. On all TPR profiles of the three doped perovskites with unity of the A-site and B-site ratio, the reduction of Ru species could not be observed at low Ru loadings (0.05% and 0.1%). A reduction peak from RuO2 particles appeared at temperatures prior to the perovskite reduction on the TPR plots of modified La0.9Sr0.1CrO3 and La0.8Sr0.2CrO3 with high Ru loading (0.5% and 1%, respectively), but it did not occur with the Ru modified La0.7Sr0.3CrO3 in the investigated Ru loading range. The TPR results of the Ru modified La0.8Sr0.2Cr0.95O3 depicted that some Ru ions might be stabilized due to the incorporation into the oxide.

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

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 220 ◽  
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.

scholarly journals Biodiesel Production on Monometallic Pt, Pd, Ru, and Ag Catalysts Supported on Natural Zeolite

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 48
Author(s):  
Pawel Mierczynski ◽  
Magdalena Mosińska ◽  
Lukasz Szkudlarek ◽  
Karolina Chalupka ◽  
Misa Tatsuzawa ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Natural Zeolite ◽  
Noble Metals ◽  
Methyl Esters ◽  
Physicochemical Characteristics ◽  
Biodiesel Production ◽  
X Ray Diffraction ◽  
X Ray ◽  
Yield Values ◽  
Temperature Programmed

Biodiesel production from rapeseed oil and methanol via transesterification reaction facilitated by various monometallic catalyst supported on natural zeolite (NZ) was investigated. The physicochemical characteristics of the synthesized catalysts were studied by X-ray diffraction (XRD), Brunauer–Emmett–Teller method (BET), temperature-programmed-reduction in hydrogen (H2-TPR), temperature-programmed-desorption of ammonia (NH3-TPD), Scanning Electron Microscope equipped with EDX detector (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) methods. The highest activity and methyl ester yields were obtained for the Pt/NZ catalyst. This catalyst showed the highest triglycerides conversion of 98.9% and fatty acids methyl esters yields of 94.6%. The activity results also confirmed the high activity of the carrier material (NZ) itself in the investigated reaction. Support material exhibited 90.5% of TG conversion and the Fatty Acid Methyl Esters yield (FAME) of 67.2%. Introduction of noble metals improves the TG conversion and FAME yield values. Increasing of the metal loading from 0.5 to 2 wt.% improves the reactivity properties of the investigated catalysts.

scholarly journals Influence of Sulfur-Containing Sodium Salt Poisoned V2O5–WO3/TiO2 Catalysts on SO2–SO3 Conversion and NO Removal

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 541 ◽  
Author(s):  
Haiping Xiao ◽  
Chaozong Dou ◽  
Hao Shi ◽  
Jinlin Ge ◽  
Li Cai
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Impregnation Method ◽  
So2 Oxidation ◽  
Sodium Salts ◽  
X Ray ◽  
Temperature Programmed ◽  
Physical Features

A series of poisoned catalysts with various forms and contents of sodium salts (Na2SO4 and Na2S2O7) were prepared using the wet impregnation method. The influence of sodium salts poisoned catalysts on SO2 oxidation and NO reduction was investigated. The chemical and physical features of the catalysts were characterized via NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed that sodium salts poisoned catalysts led to a decrease in the denitration efficiency. The 3.6% Na2SO4 poisoned catalyst was the most severely deactivated with denitration efficiency of only 50.97% at 350 °C. The introduction of SO42− and S2O72− created new Brønsted acid sites, which facilitated the adsorption of NH3 and NO reduction. The sodium salts poisoned catalysts significantly increased the conversion of SO2–SO3. 3.6%Na2S2O7 poisoned catalyst had the strongest effect on SO2 oxidation and the catalyst achieved a maximum SO2–SO3-conversion of 1.44% at 410 °C. Characterization results showed sodium salts poisoned catalysts consumed the active ingredient and lowered the V4+/V5+ ratio, which suppressed catalytic performance. However, they increased the content of chemically adsorbed oxygen and the strength of V5+=O bonds, which promoted SO2 oxidation.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

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

Catalysts ◽  
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.

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

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 90 ◽  
Author(s):  
Wangsheng Chen ◽  
Fali Hu ◽  
Linbo Qin ◽  
Jun Han ◽  
Bo Zhao ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Space Velocity ◽  
Acid Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffuse Reflectance Infrared Spectroscopy ◽  
And Performance ◽  
Diffuse Reflectance Infrared

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).

scholarly journals {CeO2/Bi2Mo1−xRuxO6} and {Au/Bi2Mo1−xRuxO6} Catalysts for Low-Temperature CO Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 947 ◽  
Author(s):  
Edson Edain González ◽  
Ricardo Rangel ◽  
Javier Lara ◽  
Pascual Bartolo-Pérez ◽  
Juan José Alvarado-Gil ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Supported Catalysts ◽  
Pollutant Emissions ◽  
Impregnation Method ◽  
Wet Impregnation ◽  
X Ray ◽  
Low Temperature Co Oxidation ◽  
Carbon Dioxide Co2 ◽  
Wet Impregnation Method

Nowadays, one of the most important challenges that humanity faces is to find alternative ways of reducing pollutant emissions. CeO2/Bi2Mo1−xRuxO6 and Au/Bi2Mo1−xRuxO6 catalysts were prepared to efficiently transform carbon monoxide (CO) to carbon dioxide (CO2) at low temperatures. The systems were prepared in a two-step process. First, Bi2Mo1−xRuxO6 supports were synthesized through the hydrothermal procedure under microwave heating. Then, CeO2 was deposited on Bi2Mo1−xRuxO6 using the wet impregnation method, while the incipient impregnation method was selected to deposit gold nanoparticles. The CeO2/Bi2Mo1−xRuxO6 and Au/Bi2Mo1−xRuxO6 catalysts were characterized using SEM microscopy and XRD. Furthermore, energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used. Tests were carried out for the supported catalysts in CO oxidation, and high conversion values, nearing 100%, was observed in a temperature range of 100 to 250 °C. The results showed that the best system was the Au/Bi2Mo0.95Ru0.05O6 catalyst, with CO oxidation starting at 50 °C and reaching 100% conversion at 186 °C.

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

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1341 ◽  
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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