Novel Preparation of Cu and Fe Zirconia Supported Catalysts for Selective Catalytic Reduction of NO with NH3

Copper and iron promoted ZrO2 catalysts were prepared by one-pot synthesis using urea. The studied catalysts were characterized by XRD, N2 physisorption, XPS, temperature-programmed desorption of NH3 (NH3-TPD), and tested by the selective catalytic reduction by ammonia (NH3-SCR) of NO in the absence and presence of water vapor, under the experimental conditions representative of exhaust gases from stationary sources. The influence of SO2 on catalytic performance was also investigated. Among the studied catalysts, the Fe-Zr sample showed the most promising results in NH3-SCR, being active and highly selective to N2. The addition of SO2 markedly improved NO and NH3 conversions during NH3-SCR in the presence of H2O. The improvement in acidic surface properties is believed to be the cause.

Download Full-text

Selective Catalytic Reduction of NO with NH3 over Ce-W-Ti Oxide Catalysts Prepared by Solvent Combustion Method

Applied Sciences ◽

10.3390/app8122430 ◽

2018 ◽

Vol 8 (12) ◽

pp. 2430 ◽

Cited By ~ 1

Author(s):

Xinbo Zhu ◽

Yaolin Wang ◽

Yu Huang ◽

Yuxiang Cai

Keyword(s):

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Space Velocity ◽

Combustion Method ◽

Catalytic Performance ◽

Solution Combustion ◽

X Ray ◽

Nh3 Scr ◽

Scr Of No ◽

Temperature Programmed

In this work, a series of Ce-W-Ti catalysts were synthesized using a solution combustion method for the selective catalytic reduction (SCR) of NO with NH3 at low temperatures. The reaction performance of NH3-SCR of NO was significantly improved over the Ce-W-Ti catalysts compared to Ce0.4Ti and W0.4Ti catalysts, while Ce0.2W0.2Ti showed the best activity among all the samples. The Ce0.2W0.2Ti catalyst exhibited over 90% removal of NO and 100% N2 selectivity in the temperature range of 250–400 °C at a gas hourly space velocity (GHSV) of 120,000 mL·g−1·h−1. The Ce-W-Ti catalysts were characterized using N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectrometry and temperature programmed desorption of NH3 to establish the structure-activity relationships of the Ce-W-Ti catalysts. The excellent catalytic performance of the Ce0.2W0.2Ti catalyst could be associated with the larger specific surface area, highly dispersed Ce and W species, increased amount of surface adsorbed oxygen (Oads) and enhanced total acidity on the catalyst surfaces.

Download Full-text

Time-resolved in situ DRIFTS study on NH3–SCR of NO on CeO2/TiO2 catalyst

Catalysis Science & Technology ◽

10.1039/d1cy02089g ◽

2022 ◽

Author(s):

Jie Yang ◽

Shan Ren ◽

Mingming Wang ◽

Zhicaho Chen ◽

Lin Chen ◽

...

Keyword(s):

Nitrogen Oxides ◽

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Time Resolved ◽

In Situ Drifts ◽

Tio2 Catalyst ◽

Nh3 Scr ◽

Scr Of No

Ce–Ti catalysts were considered as promising replacement for V–Ti based catalysts for selective catalytic reduction (SCR) of nitrogen oxides (NO and NO2) with NH3. In this work, CeO2/TiO2 catalyst was...

Download Full-text

Effect of Organic Assistant on the Performance of Ceria-Based Catalysts for the Selective Catalytic Reduction of NO with Ammonia

Catalysts ◽

10.3390/catal9040357 ◽

2019 ◽

Vol 9 (4) ◽

pp. 357 ◽

Cited By ~ 3

Author(s):

Huang ◽

Li ◽

Qiu ◽

Chen ◽

Cheng ◽

...

Keyword(s):

Selective Catalytic Reduction ◽

Ball Milling ◽

Catalytic Reduction ◽

Temperature Programmed Desorption ◽

Milling Process ◽

X Ray ◽

Ball Milling Process ◽

Nh3 Scr ◽

Temperature Programmed ◽

Catalytic Performances

In the present study, a series of CeO2/TiO2 catalysts were fabricated by dry ball milling method in the absence and presence of organic assistants, and their catalytic performances for the selective catalytic reduction (SCR) of NO by NH3 were investigated. It was found that the addition of organic assistants in the ball milling process and the calcining ambience exerted a significant influence on the catalytic performances of CeO2/TiO2 catalysts. The nitrogen sorption isotherm measurement (BET), powder X-ray diffraction (XRD), Raman spectra, high-resolution transmission electron microscopy (HR-TEM), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), sulfur dioxide temperature-programmed desorption (SO2-TPD), thermogravimetric analysis (TG), Fourier transform infrared (FT-IR) and X-ray photoelectron spectra (XPS) characterizations showed that the introduction of citric acid in the ball milling process could significantly change the decomposition process of the precursor mixture, which can lead to improved dispersion and reducibility of cerium species, surface acidity as well as the surface microstructure, all which were responsible for the high low temperature activity of CeTi-C-N in an NH3-SCR reaction. In contrast, the addition of sucrose in the milling process showed an inhibitory effect on the catalytic performance of CeO2/TiO2 catalyst in an NH3-SCR reaction, possibly due to the decrease of the crystallinity of the TiO2 support and the carbon residue covering the active sites.

Download Full-text

Preparation of Mesoporous Mn–Ce–Ti–O Aerogels by a One-Pot Sol–Gel Method for Selective Catalytic Reduction of NO with NH3

Materials ◽

10.3390/ma13020475 ◽

2020 ◽

Vol 13 (2) ◽

pp. 475

Author(s):

Yabin Wei ◽

Shuangling Jin ◽

Rui Zhang ◽

Weifeng Li ◽

Jiangcan Wang ◽

...

Keyword(s):

Selective Catalytic Reduction ◽

Lewis Acid ◽

Catalytic Reduction ◽

Sol Gel ◽

Acid Sites ◽

Lewis Acid Sites ◽

One Pot ◽

Gel Method ◽

Nh3 Scr ◽

Composite Aerogels

Novel Mn–Ce–Ti–O composite aerogels with large mesopore size were prepared via a one-pot sol–gel method by using propylene oxide as a network gel inducer and ethyl acetoacetate as a complexing agent. The effect of calcination temperature (400, 500, 600, and 700 °C) on the NH3–selective catalytic reduction (SCR) performance of the obtained Mn–Ce–Ti–O composite aerogels was investigated. The results show that the Mn–Ce–Ti–O catalyst calcined at 600 °C exhibits the highest NH3–SCR activity and lowest apparent activation energy due to its most abundant Lewis acid sites and best reducibility. The NO conversion of the MCTO-600 catalyst maintains 100% at 200 °C in the presence of 100 ppm SO2, showing the superior resistance to SO2 poisoning as compared with the MnOx–CeO2–TiO2 catalysts reported the literature. This should be mainly attributed to its large mesopore sizes with an average pore size of 32 nm and abundant Lewis acid sites. The former fact facilitates the decomposition of NH4HSO4, and the latter fact reduces vapor pressure of NH3. The NH3–SCR process on the MCTO-600 catalyst follows both the Eley–Rideal (E–R) mechanism and the Langmuir–Hinshelwood (L–H) mechanism.

Download Full-text

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

Catalysts ◽

10.3390/catal10020202 ◽

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.

Download Full-text

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

Catalysis Science & Technology ◽

10.1039/c5cy02278a ◽

2016 ◽

Vol 6 (17) ◽

pp. 6688-6696 ◽

Cited By ~ 57

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.

Download Full-text

Promotional Effect of Manganese on Selective Catalytic Reduction of NO by CO in the Presence of Excess O2 over M@La–Fe/AC (M = Mn, Ce) Catalyst

Catalysts ◽

10.3390/catal10111322 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1322

Author(s):

Fatemeh Gholami ◽

Zahra Gholami ◽

Martin Tomas ◽

Veronika Vavrunkova ◽

Somayeh Mirzaei ◽

...

Keyword(s):

Selective Catalytic Reduction ◽

Oxygen Vacancies ◽

Catalytic Reduction ◽

Catalyst Activity ◽

Double Exchange ◽

Catalytic Performance ◽

Redox Equilibrium ◽

Metal Site ◽

Promotional Effect ◽

Scr Of No

The catalytic performance of a series of La-Fe/AC catalysts was studied for the selective catalytic reduction (SCR) of NO by CO. With the increase in La content, the Fe2+/Fe3+ ratio and amount of surface oxygen vacancies (SOV) in the catalysts increased; thus the catalytic activity improved. Incorporating the promoters to La3-Fe1/active carbon (AC) catalyst could affect the catalyst activity by changing the electronic structure. The increase in Fe2+/Fe3+ ratio after the promoter addition is possibly due to the extra synergistic interaction of M (Mn and Ce) and Fe through the redox equilibrium of M3+ + Fe3+ ↔ M4+ + Fe2+. This phenomenon could have improved the redox cycle, enhanced the SOV formation, facilitated NO decomposition, and accelerated the CO-SCR process. The presence of O2 enhanced the formation of the C(O) complex and improved the activation of the metal site. Mn@La3-Fe1/AC catalyst revealed an excellent NO conversion of 93.8% at 400 °C in the presence of 10% oxygen. The high catalytic performance of MnOx and double exchange behavior of Mn3+ and Mn4+ can increase the number of SOV and improve the catalytic redox properties.

Download Full-text

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

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.2010.5534 ◽

2010 ◽

Vol 224 (06) ◽

pp. 907-920 ◽

Cited By ~ 1

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.

Download Full-text

Preparation and Performance of Cerium-Based Catalysts for Selective Catalytic Reduction of Nitrogen Oxides: A Critical Review

Catalysts ◽

10.3390/catal11030361 ◽

2021 ◽

Vol 11 (3) ◽

pp. 361

Author(s):

Ming Cai ◽

Xue Bian ◽

Feng Xie ◽

Wenyuan Wu ◽

Peng Cen

Keyword(s):

Nitrogen Oxides ◽

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Surface Acidity ◽

Catalytic Performance ◽

Synthesis Methods ◽

Preparation Methods ◽

Nh3 Scr ◽

Nox Control ◽

And Performance

Selective catalytic reduction of nitrogen oxides with NH3 (NH3-SCR) is still the most commonly used control technology for nitrogen oxides emission. Specifically, the application of rare earth materials has become more and more extensive. CeO2 was widely developed in NH3-SCR reaction due to its good redox performance, proper surface acidity and abundant resource reserves. Therefore, a large number of papers in the literature have described the research of cerium-based catalysts. This review critically summarized the development of the different components of cerium-based catalysts, and characterized the preparation methods, the catalytic performance and reaction mechanisms of the cerium-based catalysts for NH3-SCR. The purpose of this review is to highlight: (1) the modification effect of the various metal elements for cerium-based catalysts; (2) various synthesis methods of the cerium-based catalysts; and (3) the physicochemical properties of the various catalysts and clarify their relations to catalytic performances, particularly in the presence of SO2 and H2O. Finally, we hope that this work can give timely technical guidance and valuable insights for the applications of NH3-SCR in the field of NOx control.

Download Full-text

Modified Zeolite Catalyst for a NOx Selective Catalytic Reduction Process in Nitric Acid Plants

Catalysts ◽

10.3390/catal11040450 ◽

2021 ◽

Vol 11 (4) ◽

pp. 450

Author(s):

Magdalena Saramok ◽

Agnieszka Szymaszek ◽

Marek Inger ◽

Katarzyna Antoniak-Jurak ◽

Bogdan Samojeden ◽

...

Keyword(s):

Nitric Acid ◽

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Nox Reduction ◽

Reduction Process ◽

Active Phase ◽

Catalytic Performance ◽

Temperature Range ◽

Nh3 Scr ◽

Modified Clinoptilolite

Natural zeolite of the heulandite-type framework was modified with iron and tested as a catalyst for the selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR) in the temperature range of 150–450 °C. The catalyst was prepared at a laboratory scale in a powder form and then the series of experiments of its shaping into tablets was conducted. Physicochemical studies of the catalyst (N2 sorption at −196 °C, FT-IR, XRD, UV-vis) were performed to determine the textural and structural properties and identify the surface functional groups, the crystalline structure of the catalysts and the form and aggregation of the active phase. The activity tests over the shaped catalyst were performed industry-reflecting conditions, using tail gases from the pilot nitric acid plant. The influence of a temperature, catalyst load, and the amount of reducing agent (ammonia) on the NOx reduction process were investigated. The results of catalytic tests that were performed on model gas mixture showed that non-modified clinoptilolite exhibited around 58% conversion of NO at 450 °C. The temperature window of the shaped catalyst shifted to a higher temperature range in comparison to the powder sample. The catalytic performance of the shaped Fe-clinoptilolite in the industry-reflecting conditions was satisfactory, especially at 450 °C. Additionally, it was observed that the ratio of N2O concentration downstream and upstream of the catalytic bed was below 1, which indicated that the catalyst exhibited activity in both DeNOx and DeN2O process.

Download Full-text