Manganese oxides with hierarchical structures derived from coordination polymers and their enhanced catalytic activity at low temperature for selective catalytic reduction of NOx

2019 ◽  
Vol 48 (43) ◽  
pp. 16395-16401 ◽  
Author(s):  
Byeonggab Ji ◽  
Junhyung Lee ◽  
Seung-Yeop Kwak
Keyword(s):  
Catalytic Activity ◽  
Coordination Polymer ◽  
Manganese Oxides ◽  
Preparation Method ◽  
Catalytic Reduction ◽  
Hierarchical Structures ◽  
Cost Effective ◽  
Catalytic Performance ◽  
Environmentally Benign ◽  
Reduction Of Nox

Hierarchical manganese oxides for enhancing catalytic performance have been successfully synthesized via simple thermal annealing manganese coordination polymer, which is a facile, cost-effective, and environmentally benign preparation method.

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.

A facile approach to fabricate halloysite/metal nanocomposites with preformed and in situ synthesized metal nanoparticles: a comparative study of their enhanced catalytic activity

2015 ◽  
Vol 44 (19) ◽  
pp. 8906-8916 ◽  
Author(s):  
Sankar Das ◽  
Subhra Jana
Keyword(s):  
Catalytic Activity ◽  
Comparative Study ◽  
Metal Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Cost Effective ◽  
Environmentally Benign ◽  
Metal Nanocomposites

Halloysite/metal nanocomposites have been synthesized through the immobilization of preformed and in situ synthesized metal nanoparticles over halloysite surfaces, which in turn produce efficient, cost-effective, and environmentally benign heterogeneous catalysts.

scholarly journals Effect of the calcination temperature of cerium–zirconium mixed oxides on the structure and catalytic performance of WO3/CeZrO2 monolithic catalyst for selective catalytic reduction of NOx with NH3

RSC Advances ◽  
2017 ◽  
Vol 7 (39) ◽  
pp. 24177-24187 ◽  
Author(s):  
Haidi Xu ◽  
Mengmeng Sun ◽  
Shuang Liu ◽  
Yuanshan Li ◽  
Jianli Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Lewis Acid ◽  
Mixed Oxides ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Reduction Of Nox ◽  
Calcined Temperature

The calcined temperature of the carrier obviously affected SCR activity of catalysts, WO3/Ce0.68Zr0.32O2-500 showed the best low-temperature NH3-SCR activity due to its more Lewis acid sites and stronger redox property.

scholarly journals Electropositive Promotion by Alkalis or Alkaline Earths of Pt-Group Metals in Emissions Control Catalysis: A Status Report

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 157 ◽  
Author(s):  
Ioannis V. Yentekakis ◽  
Philippe Vernoux ◽  
Grammatiki Goula ◽  
Angel Caravaca
Keyword(s):  
Cost Effective ◽  
Electrochemical Promotion ◽  
Catalytic Performance ◽  
Effective Control ◽  
Status Report ◽  
Alkaline Earths ◽  
Reduction Of Nox ◽  
Electrochemical Promotion Of Catalysis ◽  
Novel Catalyst ◽  
Combustion Processes

Recent studies have shown that the catalytic performance (activity and/or selectivity) of Pt-group metal (PGM) catalysts for the CO and hydrocarbons oxidation as well as for the (CO, HCs or H2)-SCR of NOx or N2O can be remarkably affected through surface-induced promotion by successful application of electropositive promoters, such as alkalis or alkaline earths. Two promotion methodologies were implemented for these studies: the Electrochemical Promotion of Catalysis (EPOC) and the Conventional Catalysts Promotion (CCP). Both methodologies were in general found to achieve similar results. Turnover rate enhancements by up to two orders of magnitude were typically achievable for the reduction of NOx by hydrocarbons or CO, in the presence or absence of oxygen. Subsequent improvements (ca. 30–60 additional percentage units) in selectivity towards N2 were also observed. Electropositively promoted PGMs were also found to be significantly more active for CO and hydrocarbons oxidations, either when these reactions occur simultaneously with deNOx reactions or not. The aforementioned direct (via surface) promotion was also found to act synergistically with support-mediated promotion (structural promotion); the latter is typically implemented in TWCs through the complex (Ce–La–Zr)-modified γ-Al2O3 washcoats used. These attractive findings prompt to the development of novel catalyst formulations for a more efficient and cost-effective control of the emissions of automotives and stationary combustion processes. In this report the literature findings in the relevant area are summarized, classified and discussed. The mechanism and the mode of action of the electropositive promoters are consistently interpreted with all the observed promoting phenomena, by means of indirect (kinetics) and direct (spectroscopic) evidences.

The catalytic activity of CuSO4/ZrO2 for the selective catalytic reduction of NOx with NH3 in the presence of excess O2

2002 ◽  
Vol 36 (3) ◽  
pp. 217-230 ◽  
Author(s):  
Daniela Pietrogiacomi ◽  
Diana Sannino ◽  
Alessandro Magliano ◽  
Paolo Ciambelli ◽  
Simonetta Tuti ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Reduction Of Nox

Novel Fe–Ce–Ti catalyst with remarkable performance for the selective catalytic reduction of NOx by NH3

2016 ◽  
Vol 6 (17) ◽  
pp. 6688-6696 ◽  
Author(s):  
Zhiming Liu ◽  
Yuxian Liu ◽  
Biaohua Chen ◽  
Tianle Zhu ◽  
Lingling Ma
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Redox Cycle ◽  
Reaction Intermediates ◽  
Scr Of No ◽  
Reduction Of Nox

The redox cycle (Ce4+ + Fe2+ ↔ Ce3+ + Fe3+) over the Fe–Ce–Ti catalyst contributes to the activation of NOx and NH3 and thus the formation of reaction intermediates, leading to the high catalytic performance for the NH3-SCR of NOx.

Sign in / Sign up

Export Citation Format

Share Document