scholarly journals Deactivation Effect of CaO on Mn-Ce/AC Catalyst for SCR of NO with NH3 at Low Temperature

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 873 ◽  
Author(s):  
Zenghui Su ◽  
Shan Ren ◽  
Zhichao Chen ◽  
Jie Yang ◽  
Yuhan Zhou ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Low Temperature ◽  
Acid Site ◽  
Catalytic Reduction ◽  
Total Pore Volume ◽  
Bet Surface Area ◽  
Poisoning Effect ◽  
Scr Of No ◽  
Critical Reason

In this study, the poisoning effect of CaO on activated carbon (AC)-based Mn-Ce catalysts was discussed. Loading CaO inhibited the catalytic activity of the catalyst and the NO conversion of the catalyst decreased from 69.5% to 38.2% at 75 °C. The amount of MnO2 in AC surface decreased in the process of loading CaO, which was detrimental to the Selective Catalytic Reduction (SCR) performance of the catalyst. The change of manganese oxide form inhibited generation rate for the chemisorption oxygen and NO2, which was the most critical reason for the decrease of catalytic activity. Besides, loaded CaO entered into the pores of the catalyst, which led to the blockage of the pores and further resulted in the decrease of the Brunauer-Emmett-Teller (BET) surface area and total pore volume. It also destroyed the oxygen-containing functional groups and acid site on the surface of AC. All of these caused the deactivation of Mn-Ce/AC catalyst after loading CaO.

Microstructure of Porous V2O-CeO2-SiO2 Catalyst for SCR of NO with NH3 at Low Temperature

2014 ◽  
Vol 875-877 ◽  
pp. 213-217 ◽  
Author(s):  
Mohd Razali Sohot ◽  
Umi Sarah Jais ◽  
Muhd Rosli Sulaiman
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
Reduction Process ◽  
No Emission ◽  
Scr Of No ◽  
Before And After ◽  
The Right ◽  
Proven Method

Selective catalytic reduction (SCR) is a well-proven method to reduce NO emission. However, to choose the right catalyst that provides a surface for reaction between NO and ammonia at low temperatures is a challenging task for a catalysts developers. In an earlier study, we prepared V2O5-CeO2-SiO2 catalyst with increasing V2O5 content by sol-gel route and found that the catalytic activity improved with increasing the V2O5 loading up to 0.5%. The catalytic activity, however, dropped when V2O5 loading was about 1% and increased back when the loading of V2O5 was about 5%. In this study, we looked into the microstructural relationship to explain these findings. The microstructures of the catalysts before and after exposure to NO gas revealed that the catalysts with 0.2% and 0.5% V2O5 were more porous after the reduction process possibly due to improved breakdown of (NH4)HCO3 to NH3 by the possible interaction with the V2O5 and CeO2-containing catalysts which consequently resulted in a more efficient NO reduction to N2 and H2O at low temperature. The microstructure of the catalyst with 1% V2O5 content to 5%, improved back the efficiency although clogging by CeVO4 phase still possible due to its presence based on XRD. The well-ordered micropores before exposure to NO and the more efficient breakdown of (NH4)HCO3 could have contributed to increase back the catalytic activity at low temperature.

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.

Effect of Cerium on Manganese Base Catalysts by Co-Precipitation for Low-Temperature SCR of NO with NH3

2014 ◽  
Vol 633 ◽  
pp. 121-124 ◽  
Author(s):  
Liang Jing Zhang ◽  
Su Ping Cui ◽  
Hong Xia Guo ◽  
Xiao Yu Ma ◽  
Xiao Gen Luo
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Precipitation Method ◽  
Base Catalysts ◽  
Nox Conversion ◽  
Scr Of No ◽  
Co Precipitation ◽  
Low Temperature Scr

Catalysts of Mn/TiO2 and Mn-Ce /TiO2 prepared by co-precipitation method for low temperature selective catalytic reduction (SCR) of NO with NH3 were investigated in this study. The experimental results showed that co-precipitation method after improvement, the NO conversion of Mn-Ce/TiO2 catalyst increased sharply. Meanwhile, the addition of cerium has significant effects on the catalytic activity. Characterizations of catalysts were carried out by XRD, BET and H2-TPR. The characterized results indicated that co-precipitation method after improvement, in temperature windows 150 to 300 °C, showed higher NOx conversion.

V2O5-WO3/TiO2 Catalysts for Low Temperature NH3 SCR: Catalytic Activity and Characterization

2016 ◽  
Vol 697 ◽  
pp. 275-278 ◽  
Author(s):  
Yu Xin Deng ◽  
Xin Chen ◽  
Rong Shao ◽  
Li Ming Hu ◽  
Jie Tang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Surface Area ◽  
Catalytic Reduction ◽  
Anatase Phase ◽  
Systematic Investigation ◽  
Acid Sites ◽  
Bet Surface Area ◽  
Reduction Of No

A systematic investigation of the effect of WO3 loading over V2O5/TiO2 catalysts was carried out for the selective catalytic reduction of NO by NH3. The characteristics were examined use BET surface area , X-ray diffractometry (XRD) , Temperature programmed desorption (TPD) of NH3 . It was fund that the WO3 species could interact with the TiO2 anatase phase to exhibits a high activity. With increasing WO3 content ,the activity of V-W/TiO2 for the selective catalytic reduction of NO by NH3 was improved at low temperatures in the range of 3～7%. The results showed that the adding of WO3 to V2O5/TiO2 could result in exposing acid sites of catalysts doped WO3 at low temperature. Furthermore, especially the catalytic activity of VW7Ti showed higher than 80% at 180 °C. However, the catalytic BET surface area and the mass of acid sites not play a leading role for improving low-temperature activity of VWTi in this paper.

scholarly journals The Poisoning Effect of Na Doping over Mn-Ce/TiO2Catalyst for Low-Temperature Selective Catalytic Reduction of NO by NH3

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Liu Yang ◽  
Yue Tan ◽  
Zhongyi Sheng ◽  
Aiyi Zhou
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Chemical Properties ◽  
Impregnation Method ◽  
Negative Effects ◽  
Poisoning Effect ◽  
Surface Areas ◽  
Physical And Chemical

Sodium carbonate (Na2CO3), sodium nitrate (NaNO3), and sodium chloride (NaCl) were chosen as the precursors to prepare the Na salts deposited Mn-Ce/TiO2catalysts through an impregnation method. The influence of Na on the performance of the Mn-Ce/TiO2catalyst for low-temperature selective catalytic reduction ofNOxby NH3was investigated. Experimental results showed that Na salts had negative effects on the activity of Mn-Ce/TiO2and the precursors of Na salts also affected the catalytic activity. The precursor Na2CO3had a greater impact on the catalytic activity, while NaNO3had minimal effect. The characterization results indicated that the significant changes in physical and chemical properties of Mn-Ce/TiO2were observed after Na was doped on the catalysts. The significant decreases in surface areas and NH3adsorption amounts were observed after Na was doped on the catalysts, which could be considered as the main reasons for the deactivation of Na deposited Mn-Ce/TiO2.

Modification of Nano Spherical-Like MnOx/TiO2 Catalysts with F-Doped

2017 ◽  
Vol 898 ◽  
pp. 1896-1904
Author(s):  
Jun Lin Xie ◽  
Feng Xiang Li ◽  
Hai Feng Cui ◽  
Feng He ◽  
Kai Qi
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Spherical Particle ◽  
Surface Area ◽  
Catalytic Reduction ◽  
Sol Gel ◽  
Acid Sites ◽  
Scr Of No ◽  
Structures And Properties

A series of spherical-like MnOx/TiO2 catalysts with F-doped were prepared by using sol-gel method and investigated for low-temperature selective catalytic reduction (SCR) of NOx with NH3 at the temperature ranging from 100 °C to 200 °C. The 0.07Ce-MnOx/TiO2 catalyst shows the highest activity and yields 95% NO conversion at 200 °C. With the help of XRD, TGA, H2-TPR, NH3-TPD, BET and TEM, the structures and properties of the catalysts were characterized. The results show that it is a fine modifier for TiO2 support with appropriate amounts of F doping, and F ions can enter into TiO2 lattice, reducing the formation of rutile TiO2 and the crystallization of MnOx. However, MnTiO3 was generated in the catalysts with excess F doping. This would cause larger diameter of spherical particle and smaller surface area. But the amounts of the surface acid sites increased, and the reduction ability of catalysts was enhanced, which is beneficial for catalytic activity of the catalysts.

scholarly journals Preparation of High-Performance Activated Carbon from Coffee Grounds after Extraction of Bio-Oil

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 257
Author(s):  
Jie Ren ◽  
Nanwei Chen ◽  
Li Wan ◽  
Guojian Li ◽  
Tao Chen ◽  
...  
Keyword(s):  
Activated Carbon ◽  
High Performance ◽  
Average Pore Size ◽  
Total Pore Volume ◽  
Micropore Volume ◽  
Bet Surface Area ◽  
Average Pore ◽  
Activation Temperature ◽  
Coffee Grounds ◽  
Bio Oil

In this study, a new method for economical utilization of coffee grounds was developed and tested. The resulting materials were characterized by proximate and elemental analyses, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N2 adsorption–desorption at 77 K. The experimental data show bio-oil yields reaching 42.3%. The optimal activated carbon was obtained under vacuum pyrolysis self-activation at an operating temperature of 450 °C, an activation temperature of 600 °C, an activation time of 30 min, and an impregnation ratio with phosphoric acid of 150 wt.%. Under these conditions, the yield of activated carbon reached 27.4% with a BET surface area of 1420 m2·g−1, an average pore size of 2.1 nm, a total pore volume of 0.747 cm3·g−1, and a t-Plot micropore volume of 0.428 cm3·g−1. In addition, the surface of activated carbon looked relatively rough, containing mesopores and micropores with large amounts of corrosion pits.

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