Effect of CO2/O2 on Catalytic Reduction of NO by Iron

2012 ◽  
Vol 616-618 ◽  
pp. 1849-1852 ◽  
Author(s):  
A Long Su ◽  
Ya Xin Su ◽  
Hao Cheng
Keyword(s):  
Flue Gas ◽  
No Reduction ◽  
Catalytic Reduction ◽  
X Ray Diffraction ◽  
Sudden Drop ◽  
Reduction Of No ◽  
X Ray ◽  
Reduction Efficiency ◽  
Different Temperatures ◽  
Temperature Programmed

This paper presents the results of the reaction between metallic iron mesh rolls and NO in the presence of CO2/O2 at different temperatures. All experiments were carried out in a ceramic tube controlled by the temperature programmed electrical furnace. About 99% NO reduction was achieved when temperature was above 700°C in the absence of CO2/O2. Results showed that CO2 in the flue gas had little effect on the NO reduction. NO reduction efficiencies were observed to exceed 95% for all CO2 concentrations at above 700°C. The addition of O2, however, caused a sudden drop by about 76% in NO reduction efficiency. Scanning electron microscope (SEM) results showed that the oxidation of iron in O2 atmosphere led to a more continuous and impervious oxide layer than that in CO2 atmosphere. Results using X-ray diffraction (XRD) to detect the iron samples after reactions revealed that FeO, Fe3O4, Fe and Fe2O3 were formed in CO2 atmosphere, but Fe3O4 and Fe2O3 were formed when O2 was added.

Experimental Study of NO Reduction by Iron in CO Atmosphere

2012 ◽  
Vol 518-523 ◽  
pp. 2138-2142 ◽  
Author(s):  
Ya Xin Su ◽  
A Long Su ◽  
Hao Cheng
Keyword(s):  
Nitric Oxide ◽  
Flue Gas ◽  
Metallic Iron ◽  
No Reduction ◽  
Tubular Reactor ◽  
Gas Analyzer ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Reduction Efficiency

This paper presents the results of reduction of nitric oxide, NO, by metallic iron in a one-dimensional electrically heated ceramic tubular reactor in the temperature range of 300 °C to 1200 °C with simulated flue gas of 0.05% NO in N2 base. Several sizes of iron mesh rolls were used as iron samples and were placed in the centre of the reactor. The effect of CO on NO reduction was examined by introducing 0.1% CO into the flue gas. Effluent NO was measured as a function of temperature by online gas analyzer. The chemical changes of the iron samples after the reaction were analyzed by X-ray diffraction (XRD) methods. Results showed that iron mesh roll was very effective to reduce NO to N2. When the temperature was higher than 900°C, the NO reduction efficiency was observed to exceed 90% for all the mesh rolls used. Fe2O3 was formed at the surface of the iron mesh. The presence of CO increased the NO reduction efficiency by reducing the iron oxide, mainly Fe2O3, to metallic iron.

Effect of the Addition of In to Co/HMCM-49 Catalyst for the Selective Catalytic Reduction of NO Under Lean-burn Conditions

2010 ◽  
Vol 224 (06) ◽  
pp. 907-920 ◽  
Author(s):  
Fei Li ◽  
Dehai Xiao ◽  
Jing Li ◽  
Xiangguang Yang
Keyword(s):  
Selective Catalytic Reduction ◽  
Wide Temperature Range ◽  
Catalytic Reduction ◽  
Temperature Programmed Desorption ◽  
X Ray Diffraction ◽  
Lean Burn ◽  
Reduction Of No ◽  
X Ray ◽  
Scr Of No ◽  
Temperature Programmed

AbstractSelective catalytic reduction (SCR) of NO with propane using bimetals (3Co2Ce, 3Co2Sr, 3Co2Sn and 3Co2In) loaded on HMCM-49 zeolite was studied under lean-burn condition. Only 3Co2In/HMCM-49 exhibited higher deNOx activity in a wide temperature range. The catalysts were characterized by N2-adsoption, X-ray diffraction (XRD), temperature-programmed surface reactions (TPSR) and temperature-programmed desorption (TPD) of NO. TPSR and TPD results exhibited that the addition of In inhibited the oxidation ability of Co on 3Co2In/HMCM-49 catalyst, but enhanced NOx adsorption.

Selective catalytic reduction of NO by Co-Mn based nanocatalysts

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vahid Zabihi ◽  
Mohammad Hasan Eikani ◽  
Mehdi Ardjmand ◽  
Seyed Mahdi Latifi ◽  
Alireza Salehirad
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Energy Dispersive ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
Acidic Sites ◽  
Temperature Window ◽  
Temperature Programmed

Abstract One of the most significant aspects in selective catalytic reduction (SCR) of nitrogen oxides (NOx) is developing suitable catalysts by which the process occurs in a favorable way. At the present work SCR reaction by ammonia (NH3-SCR) was conducted using Co-Mn spinel and its composite with Fe-Mn spinel, as nanocatalysts. The nanocatalysts were fabricated through liquid routes and then their physicochemical properties such as phase composition, degree of agglomeration, particle size distribution, specific surface area and also surface acidic sites have been investigated by X-ray diffraction, Field Emission Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy, energy dispersive spectroscopy mapping, Brunauer–Emmett–Teller, temperature-programmed reduction (H2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD) analysis techniques. The catalytic activity tests in a temperature window of 150–400 °C and gas hourly space velocities of 10,000, 18,000 and 30,000 h−1 revealed that almost in all studied conditions, CoMn2O4/FeMn2O4 nanocomposite exhibited better performance in SCR reaction than CoMn2O4 spinel.

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.

The Effect of Doping Ce and Fe on the Mn/TiO2 Catalyst for Low Temperature NO Selective Catalytic Reduction with NH3

2012 ◽  
Vol 260-261 ◽  
pp. 1041-1046 ◽  
Author(s):  
Shi Ye Feng ◽  
Pan Gao ◽  
Chang Qing Dong ◽  
Qiang Lu
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Titanium Oxide ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Reduction Of No ◽  
X Ray ◽  
Cerium Oxides ◽  
Oxide Support

A series of manganese-cerium oxide support titanium oxide with different Fe/Ti, Ce/Ti ratio were investigated for selectivity catalytic reduction of NO low at temperature with NH3 as a reducing agent. The catalysts base Mn/TiO2were prepared by sol-gel. The effect of amount of Ce and Fe oxide on the NO conversion of Mn/TiO22was studied. X-ray diffraction (XRD), temperature program desorption (TPD) were carried out. It was known that cerium oxides and iron oxide promoted preformance of Mn/TiO2 for low temperature. because Lewis is mainly take important role in the reaction for low temperature.

scholarly journals Modification of V2O5-WO3/TiO2 Catalyst by Loading of MnOx for Enhanced Low-Temperature NH3-SCR Performance

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1900
Author(s):  
Xianlong Zhang ◽  
Qinchao Diao ◽  
Xiaorui Hu ◽  
Xueping Wu ◽  
Kesong Xiao ◽  
...  
Keyword(s):  
Manganese Oxides ◽  
Catalytic Reduction ◽  
In Situ Growth ◽  
X Ray Diffraction ◽  
Scr Catalyst ◽  
X Ray ◽  
Nh3 Scr ◽  
Growth Method ◽  
Temperature Programmed

V2O5-WO3/TiO2 as a commercial selective catalytic reduction (SCR) catalyst usually used at middle-high temperatures was modified by loading of MnOx for the purpose of enhancing its performance at lower temperatures. Manganese oxides were loaded onto V-W/Ti monolith by the methods of impregnation (I), precipitation (P), and in-situ growth (S), respectively. SCR activity of each modified catalyst was investigated at temperatures in the range of 100–340 °C. Catalysts were characterized by specific surface area and pore size determination (BET), X-ray diffraction (XRD), temperature programmed reduction (TPR), etc. Results show that the loading of MnOx remarkably enhanced the SCR activity at a temperature lower than 280 °C. The catalyst prepared by the in-situ growth method was found to be most active for SCR.

The Effect of Thermal Treatment on the Structure of Palygorskite Used for Flue Gas SO2 Removal

2011 ◽  
Vol 356-360 ◽  
pp. 698-703 ◽  
Author(s):  
Xian Long Zhang ◽  
Wei Ping Jiang ◽  
Xue Ping Wu ◽  
Bo Wen Shi ◽  
Bao Jun Yang ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Structural Properties ◽  
Flue Gas ◽  
Temperature Programmed Desorption ◽  
Flue Gas Desulfurization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Sites ◽  
Transmission Electron ◽  
Temperature Programmed

Palygorskite is widely used as industrial adsorbent and also potential for flue gas desulfurization by adsorption of SO2. The effect of thermal treatment on Palygorskite’s structural properties and its performance in SO2adsorption were investigated. The textural and structural properties of the prepared palygorskite adsorbent were characterized by X-ray diffraction, transmission electron microscopy and temperature programmed desorption. The result showed the channel of Palygorskite is partial collapsed and the structure is not changed ultimately when thermally treated below 300 °C. The structure of Palygorskite is Gradually changed when the treating temperature is higher than 300 °C and is damaged entirety till 800 °C. As a result, the adsorption capacity of SO2on Palygorskite decreased drastically. It is suggested that the presences of surface adorbed water and zeolitic water which occupy a large number of adsorption sites are disadvantage for the adsorption of SO2, and dissimilarly the presence of crystal-bonded water is favorable.

Synthesis and Characterization of Co/SBA-15 Catalysts

2016 ◽  
Vol 881 ◽  
pp. 35-40
Author(s):  
Franciele Oliveira Costa ◽  
Carla Gabriela Azevedo Misael ◽  
André Miranda da Silva ◽  
Bianca Viana de Sousa
Keyword(s):  
Molecular Sieve ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Wet Impregnation ◽  
X Ray ◽  
Different Temperatures ◽  
Temperature Programmed

The mesoporous silica SBA-15 molecular sieve has been widely studied due to its unidirectional mesoporous structure, its high average pore diameter, its high thermal and hydrothermal stability and its ability to absorb metal ions, allowing its use as support material for catalysts. This study aimed to synthesize the Co/SBA-15 catalyst, and characterize it through the techniques of X-ray diffraction, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The SBA-15 support was synthesized from the following molar composition of reaction mixture: 1TEOS: 0.017 P123: 5.7 HCl: 173 H2O: 40 EtOH, and after calcined at 550 °C for 6 hours. The Co/SBA-15 catalyst was prepared by incorporating 10% cobalt by wet impregnation. Through the X-ray diffractograms, it was found that the impregnation has not changed the structure of the material. RTP profiles showed the presence of peaks at different temperatures that may be caused by dispersion of the cobalt.

Oxidation of thiophene over copper-manganese mixed oxides

2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Małgorzata Szynkowska ◽  
Aneta Węglińska ◽  
Elżbieta Wojciechowska ◽  
Tadeusz Paryjczak
Keyword(s):  
Noble Metals ◽  
Mixed Oxides ◽  
Diffraction Method ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Manganese ◽  
Different Temperatures ◽  
Temperature Programmed ◽  
Lower Temperature

AbstractCommercial hopcalite calcined at different temperatures and hopcalite modified with noble metals (Pt, Pd, and Au) were studied in oxidation of thiophene. Surface and bulk properties of catalysts were studied using temperature-programmed reduction (TPRH2), X-ray diffraction method (XRD) and thermal analysis (TG-DTA-MS). It was shown that calcined samples displayed higher activity in comparison with commercial untreated hopcalite; however, a lower temperature of calcination was favourable. High temperature of thermal treatment induced an increase in the crystallinity and a decrease in the surface area of the samples, and, as a consequence, the loss of catalysts activity. Moreover, marked improvement in the catalytic performance of platinum and palladium modified catalysts in relation to base hopcalite was observed. The obtained results indicate that the higher activity of samples containing Pt and Pd was accompanied by better reducibility of the catalysts.

scholarly journals Precursor Effect on Mn-Fe-Ce/TiO2 Catalysts for Selective Catalytic Reduction of NO with NH3 at Low Temperatures

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 259
Author(s):  
Siva Sankar Reddy Putluru ◽  
Leonhard Schill ◽  
Anker Degn Jensen ◽  
Bernard Siret ◽  
Frank Tabaries ◽  
...  
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Photoelectron Spectroscopy ◽  
Catalytic Reduction ◽  
Reduction Of No ◽  
X Ray ◽  
Nh3 Scr ◽  
Fast Scr ◽  
Oxide Phases ◽  
Temperature Programmed

Preparation of Mn/TiO2, Mn-Fe/TiO2, and Mn-Fe-Ce/TiO2 by the deposition-precipitation (DP) method can afford very active catalysts for low-temperature NH3-SCR (selective catalytic reduction of NO with NH3). The effect of precursor choice (nitrate vs. acetate) of Mn, Fe, and Ce on the physiochemical properties including thermal stability and the resulting SCR activity were investigated. The resulting materials were characterized by N2-Physisorption, XRD (Powder X-ray diffraction), XPS (X-ray photoelectron spectroscopy), H2-TPR (temperature-programmed reduction with hydrogen), and the oxidation of NO to NO2 measured at 300 °C. Among all the prepared catalysts 5MnAce/Ti, 25Mn0.75AceFe0.25Nit/Ti, and 25Mn0.75AceFe0.20NitCe0.05Ace/Ti showed superior SCR activity at low temperature. The superior activity of the latter two materials is likely attributable to the presence of amorphous active metal oxide phases (manganese-, iron- and cerium-oxide) and the ease of the reduction of metal oxides on TiO2. Enhanced ability to convert NO to NO2, which can promote fast-SCR like pathways, could be another reason. Cerium was found to stabilize amorphous manganese oxide phases when exposed to high temperatures.

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