scholarly journals Selective Catalytic Reduction of NO by NH3 over Mn–Cu Oxide Catalysts Supported by Highly Porous Silica Gel Powder: Comparative Investigation of Six Different Preparation Methods

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 702
Author(s):  
Davyd Urbanas ◽  
Edita Baltrėnaitė-Gedienė

In this study, Mn-based catalysts supported by highly porous silica gel powder (SSA up to 470 m2·g−1 and total pore volume up to 0.8 cm3·g−1) were prepared by six different methods in liquid solutions (electroless metal deposition, stepwise addition of a reducing agent, wet impregnation, incipient wetness impregnation, urea hydrolysis, and ammonia evaporation) and tested for selective catalytic reduction of NOx with ammonia (NH3-SCR de-NOx). Prior to the activity test all the catalysts prepared were characterized by ICP-OES, SEM, EDX mapping, XPS, XRD and N2 adsorption techniques to provide the comprehensive information about their composition and morphology, investigate the dispersion of active components on the carrier surface, identify the chemical forms and structural properties of the catalytically active species of the catalysts prepared. The results revealed that all the methods applied for preparation of SCR de-NOx catalysts can ensure the uniform distribution of Mn species on the carrier surface, however as it is typical for preparation techniques in a liquid phase the significant reduction in SSA and pore volume along with increasing the loading was observed. Considering both the physicochemical properties and the catalytic performance of the catalysts the least effective preparation method was shown to be ammonia evaporation, while the most attractive techniques are incipient wetness impregnation and electroless metal deposition.

ChemInform ◽  
2010 ◽  
Vol 28 (48) ◽  
pp. no-no
Author(s):  
J. WEN ◽  
B. DHANDAPANI ◽  
S. T. OYAMA ◽  
G. L. WILKES

1997 ◽  
Vol 9 (9) ◽  
pp. 1968-1971 ◽  
Author(s):  
J. Wen ◽  
B. Dhandapani ◽  
S. T. Oyama ◽  
G. L. Wilkes

2020 ◽  
Vol 2 (1) ◽  
pp. 33
Author(s):  
Davyd Urbanas ◽  
Pranas Baltrėnas ◽  
Saeed Saedy ◽  
Aristeidis Goulas ◽  
J. Ruud van Ommen

Based on the 2019 report of the European Environment Agency on Air Quality in Europe nitrogen oxides (NOx) were identified as the most harmful air pollutants in terms of damage to ecosystems. Moreover, in Europe, NO2 is pinpointed as one of the most dangerous pollutants for human health. Anthropogenic emissions of NOx are mainly generated by the combustion of fossil fuels. Nitrogen oxides being emitted into the atmosphere cause environmental problems such as acid rain, acidification of soil, lakes and rivers, eutrophication and photochemical smog. The most effective and widely applicable technology to date for the purification of flue gases from NOx is selective catalytic reduction using ammonia (NH3-SCR de-NOx). Nowadays, one of the most significant research fields in NH3-SCR de-NOx is the application of unconventional reduction methods and the preparation of novel catalysts possessing high specific surface area, uniformity, dispersion of active sites, activity and selectivity. Atomic layer deposition (ALD) is an attractive technique for the deposition of uniformly distributed active catalytic layers, or nanoparticles, on highly porous substrates characterized by a complex structure. For this type of materials, conventional catalyst preparation methods (e.g., impregnation or deposition precipitation) can encounter several limitations. The significant advantage of ALD for the preparation of supported catalysts is that the process can be controlled on the atomic scale, providing the required thickness of an active layer, synthesized with a sub-nm accuracy. Moreover, ALD ensures the formation of catalytic sites from the gas phase, which enhances the possibility of active species being deposited inside pores which are very small in size. In this study, ALD was applied to the preparation of VxOy-based NH3-SCR de-NOx catalysts. Highly porous silica gel powder (63–100 μm) with a specific surface area of up to 450 m2·g−1 was used as a substrate for VxOy/SiO2 with different metal loadings (wt.%). In addition (VxOy+TiO2)/SiO2 catalysts were prepared by applying vanadium (V) tri-i-propoxy oxide (VTIP) and titanium tetrachloride (TiCl4) as precursors with deionized water as the co-reactant. Elemental analysis (ICP-OES) revealed that vanadium loadings of the VxOy/SiO2 catalysts were 0.3, 0.7, 1.1 and 1.60 wt.%, while the loadings in the TiO2-promoted VxOy/SiO2 catalyst were 1.0 and 0.2 wt.% for V and Ti, respectively. The obtained XPS spectra indicated the presence of V2O3 and V2O5 species (V2O5/V2O3 ratio was 1.6 and 6.3 for the as-synthesized and calcined samples respectively). Vanadium(V) oxide is known to be a catalytically active compound for NH3-SCR de-NOx. Additionally, TEM, XRD and N2 adsorption (BET) analyses were conducted to provide a comprehensive characterization of the species size, crystalline phase and porosity of the catalysts prepared.


1995 ◽  
Vol 190 (3) ◽  
pp. 206-211 ◽  
Author(s):  
S. Satoh ◽  
I. Matsuyama ◽  
K. Susa

2008 ◽  
Vol 18 (24) ◽  
pp. 2833 ◽  
Author(s):  
Joanna Claire Rooke ◽  
Alexandre Léonard ◽  
Hugo Sarmento ◽  
Jean-Pierre Descy ◽  
Bao-Lian Su

2015 ◽  
Vol 1088 ◽  
pp. 569-572
Author(s):  
Zhi Hao Zhang ◽  
Yang Li ◽  
Yun Fang Qi ◽  
Qing Ye ◽  
Shu Lan Ji ◽  
...  

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.


Sign in / Sign up

Export Citation Format

Share Document