JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Ruoyuan Li,Aixia Li,Junhua Li,Yao Wang,Zhiming Liu
Selective catalytic reduction of NO x by CO (CO-SCR) in the presence of O 2 is challenging because in this process CO is prone to being oxidized by O 2 , thus inhibiting NO x reduction by CO. Furthermore, SO 2 typically leads to the deactivation of the CO-SCR catalyst. Herein, a significant promoting effect of SO 2 on Ir/SiO 2 catalyst for the CO-SCR of NO x in the presence of O 2 is reported. In-situ X-ray Absorption Fine Structure (XAFS) and X-ray photoelectron spectroscopy (XPS) analysis showed that SO 2 does not affect the chemical nature of Ir 0 under reaction conditions. However, SO 2 can be oxidized to sulfate and deposit on the catalyst surface. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis demonstrated that the presence of SO 2 can inhibit the CO + O 2 reaction, thus leaving more CO available to reduce NO x over the active Ir 0 sites. As a result, the reduction of NO x is remarkably promoted even in the presence of O 2 and SO 2 .
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Zhi Liu,Minmin Wang,Shoujie Liu,Zheng Chen,Lingzhi Yang,Kaian Sun,Yanju Chen,Lingyou Zeng,Wenhong Wang,Jinchong Zhao,Guangxun Sun,Bin Liu,Yuan Pan,Yunqi Liu,Chenguang Liu
The biggest challenge for selective catalytic reduction (SCR) of NO by NH 3 at low temperatures is to develop robust catalysts with high resistance to SO 2 . Mn-based catalysts have attracted great attention for their excellent activity, but the poor SO 2 resistance limits their application. Herein, we report a novel assembled composite featuring Mn 3 O 4 nanoparticles embedded in defect-abundant graphitic carbon frame (Mn 3 O 4 @G-A) via a confinement–pyrolysis–oxidation strategy derived from MOF. The Mn 3 O 4 @G-A exhibits excellent activity (reaching over 90 % NO conversion in 100, 000 h −1 GHSV at 160 °C) and significantly improved SO 2 resistance in comparison to pristine Mn 3 O 4 , and all the performance tests were conducted with 5.6 vol.% water vapor. By combining synchrotron radiation-based X-ray absorption spectroscopy and density functional theory calculation, we further discovered the positive role and the origin of graphitic carbon for improving SO 2 resistance. Over the Mn 3 O 4 @G-A sample, the electrons can be transferred from graphitic carbon to Mn 3 O 4 nanoparticles, which can regulate the electronic properties and oxidizing ability of Mn 3 O 4 nanoparticles. The proper oxidizing ability of Mn 3 O 4 @G-A can inhibit the oxidation of SO 2 to SO 3 , thus further avoid the formation of NH 4 HSO 4 and improve the SO 2 resistance. Our work here not only solves the current problem of poor SO 2 resistance of Mn-based catalysts, but also provides new insights into the design and synthesis of MOF-derived graphitic carbon-containing catalysts for SCR applications.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 22
·27663-27673
·
IF 3.056
Liu Yuan-zhen,Xu Qi-yan,Guo Rui-tang,Duan Chao-peng,Wu Gui-lin,Miao Yu-fang,Gu Jing-wen
The Cu/TiO 2 catalysts with the addition of Eu were developed by the sol-gel way for the selective catalytic reduction (SCR) of NO x by NH 3 . Activity tests revealed that CuEu/TiO 2 -0.15 catalyst showed the optimal de-NO x performance in a wide temperature range (150–300 °C), along with an admirable SO 2 tolerance. According to characterization analysis, the relationship between the NH 3 -SCR performance and physicochemical characters of samples was explored. The adjunction of Eu on Cu/TiO 2 catalyst can contribute to the formation of a large amount of Cu 2+ , adsorbed oxygen, and acid sites on the catalyst surface. Moreover, the Eu addition on Cu/TiO 2 is favorable to the generation of activated NO x and NH 3 substances adsorbed on the catalyst surface, which would conduce to the NH 3 -SCR process by Langmuir-Hinshelwood (L-H) mechanism effectively.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Hanzi Liu,Yi Zhang,Haiming Wang,Changfu You
Selective non-catalytic reduction of NOx (SNCR) with NH 3 is commonly used in industrial facilities like circulating fluidized bed (CFB) furnaces. However, the strongly temperature-dependent de-NOx feature confines its applications in a specific temperature range (900–1050 °C). Here, we report a new strategy on using Fe-Ni-W exchanged zeolite (0.5FNW-H) as a catalyst to extend the SNCR temperature window. In the CFB reactor, a significant NOx conversion improvement ranging from 14.1% to 80.9% was achieved at 700 to 850 °C by applying the developed catalyst. Catalyst dosage of 4500 h −1 (GHSV), a particle diameter of 0.1–0.3 mm, and NH 3 injection position at the dense-phase zone were found preferred for NOx reduction with the highest efficiency of ~85% at 700 °C. The physicochemical properties of the catalysts remained stable after the circulating reactions in the CFB reactor. The developed catalyst is particularly applicable for improving the SNCR performance when the thermal power plants are operated at low loads.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Benyong Yang,Wentao Mu,Benedict Tsz Woon Lo,Sijie Liu,Zhihang Chen,Liam John France,Xuehui Li
NOx and CO formation is, at present, a consequence arising from fuel production, but their emission need not be. In this study, a series of novel Ir-containing TiO2-nanobelt catalysts were designed and prepared for the simultaneous removal of NOx and CO. Activity data demonstrates that the TiO2(B) support promotes NO reduction compared to anatase. Furthermore, reaction efficiency (RE), a measure of NOx consumption vis-à-vis that of CO, reveals that catalysts containing anatase promote CO oxidation more so than their TiO2(B) counterparts. Increasing Ir concentration over the latter promotes low-temperature catalytic performance, an effect believed to be linked to the formation of Ir0–IrO2 composites. In situ DRIFTS experiments reveal the relevance of nitrite/nitrate formation and consumption at 250 °C, a mechanism insinuated by the RE value. However, at 300 °C, both TOF and RE increase, signifying the participation of a faster and more-selective reaction, which appears consistent with the isocyanate-mediated pathway.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2015
·Vol. 5
·期 4
·2260-2269
·
IF 5.426
Qiulin Zhang,Xin Liu,Ping Ning,Zhongxian Song,Hao Li,Junjie Gu
Mesoporous Ce–Ti–MoOx catalysts have been prepared by stabilization with an in situ formed carbon template and used for selective catalytic reduction of NOx with NH3 (NH3-SCR). The Ce–Ti–MoOx catalysts were characterized by N2 adsorption–desorption, XRD, HR-TEM, H2-TPR and XPS analysis. It was found that the stabilization with a carbon template obviously improved the NOx conversion of the Ce–Ti–MoOx catalyst and the pore distribution. The Ce–Ti–MoOx catalyst stabilized with a carbon template at 850 °C in N2 exhibited the best NH3-SCR activity and showed a uniform mesopore distribution, and more than 90% NOx conversions were obtained at 175–425 °C with a GHSV of 60 000 h−1. The high stabilization temperature with a carbon template in N2 not only led to an increase in specific surface area, pore volume and low-temperature SCR activity, but also contributed to the enhanced redox properties, highly dispersed titanium or molybdenum species and narrow mesopore distribution. The treatment of Ce–Ti–MoOx with a high calcination temperature for removal of the carbon template led to a drastic decrease in surface area, an abrupt decrease in surface oxygen and cerium, production of rutile TiO2, and a correspondingly low SCR activity.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Minghu Zhao,Junyi Chen,Fei Wu,Yungang Wang,Kai Chen,Chao Xiong,Rongshu Zhu
Rationally designing catalysts suitable for flue gas purification at low temperatures and unraveling the anti-poisoning mechanism at the atomic level remain challenges. Here, a highly dispersed Ni-doped MnO x catalyst (Ni 0.1 Mn 0.9 O x ) was constructed and applied for selective catalytic reduction (SCR) of nitrogen oxides (NO x ). The long-term stability of Ni 0.1 Mn 0.9 O x is up to 80% (180 ℃) after 18 h under SO 2 and H 2 O conditions. This is due to the fact that the highly dispersed Ni atoms enhance the redox and surface acidity of MnO x , and modulate the electronic structure of the active Mn sites. The denitrification reaction on Ni 0.1 Mn 0.9 O x mainly follows the Eley-Rideal mechanism. The anti-poisoning mechanism is that the introduction of Ni weakens the electron transfer between the Mn site and SO 2 , thereby inhibiting the adsorption of SO 2 . In particular, the H 2 O adsorbed on the Ni sites is decomposed to replenish the depleted Brønsted acid sites, which facilitates the adsorption of NH 3 . However, an excess of H 2 O can have an inhibitory effect. In addition, the mesoporous structure may increase the mass transfer rate and reduce the accumulation of harmful substances. This study provides viable insights for the design of SCR catalysts with excellent anti-poisoning ability.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2018
·Vol. 34
·期 4
·661-664
·
IF 1.248
Yi Ting,Li Jingwei,Zhang Yibo,Yang Xiangguang
Hollow-ZSM-5 was synthesized by a traditional hydrothermal method without alcohol, and a novel na-no-sized Ce-Cu/hollow ZSM-5 sample was prepared by conventional incipient wetness impreganation. The catalysts were characterized by TEM, SEM, XRD, NMR and N 2 adsorption-desorption. The results indicate that the hollow-ZSM-5 has a good MFI structure with large surface area. The synthesized CeO 2 -CuO/hollow ZSM-5 showed an excellent catalytic activity for NO x conversion(90% NO x conversion were obtained) in the temperature range of 340–550 °C under GHSV=480000 mL·g ‒1 ·h ‒1 due to its appropriate redox ability and acidity.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2019
·Vol. 65
·期 10
·e16684
·
IF 3.463
Lei Song,Kui Ma,Wen Tian,Junyi Ji,Changjun Liu,Siyang Tang,Wei Jiang,Hairong Yue,Bin Liang
A novel FeTiSO x catalyst prepared by a simple hydrolysis coprecipitation method was used for the selective catalytic reduction (SCR) of NO x with NH 3 , which exhibited high catalytic activity (NO x conversion of >97% and N 2 selectivity of >95%) and tolerance for both H 2 O and SO 2 at a broad temperature window of ~325–475°C. The characterization results showed that the formation of Fe–O–Ti and Fe–O–S species could significantly enhance the acidic sites of the catalyst, which play an important role in NH 3 absorption and their catalytic activity. The Fe 3+ ions in the bulk anatase TiO 2 could significantly enhance the redox properties for the SCR reaction and suppress the side reaction of NH 3 oxidation to NO or N 2 O. In addition, the reaction mechanism was discussed based on in situ diffuse reflectance infrared Fourier transform spectroscopy measurements and kinetic investigation, indicating that the reaction was dominated by the Eley–Rideal mechanism over the FeTiSO x catalyst.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Beilong Lin,Ziyang Guo,Jianhan Li,Gaofei Xiao,Daiqi Ye,Yun Hu
It is a major challenge to achieve effective synergistic reduction of NO x and VOCs in coal-fired flue gas under complex working conditions. In this work, V-Cu bimetallic oxide catalysts with different supports were designed. V1-Cu5 bimetallic oxide supported on TiO 2 showed significantly higher activity for simultaneous toluene oxidation and NO x reduction than that supported on ZSM-5, SiO 2 and γ-Al 2 O 3 . Meanwhile, it exhibited excellent stability and anti-poisoning performance, and could block the formation of toxic polycyclic aromatic hydrocarbons in by-products. Compared with ZSM-5, SiO 2 and γ-Al 2 O 3 , TiO 2 as support was conducive to the formation of abundant acidic sites and oxygen vacancies. In addition, the strong interaction between the metal active sites and TiO 2 accelerated the electron transfer from Cu to adsorbed O 2 , thus promoting the formation of active O 2− . This work can provide guidance for the development of catalysts designed for the simultaneous catalytic removal of NO x and VOCs.
研究领域:
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yuting Hu,Minghu Zhao,Bo Du,Ting Cheng,Zhaozhong Jiang,Kai Qin,Chengzhu Zhu
A series of M-MnCeO X catalysts using MOF (Metal-organic Framework) were prepared to apply for NH 3 -SCR (Selective Catalytic Reduction) of NO X . The effects of Mn/Ce molar ratio, calcination temperature and its activity including catalytic activity, H 2 O/SO 2 resistance and stability were systematically investigated. The results showed that under the Mn/Ce molar ratio of 1 and calcination temperature of 400 ℃, the catalyst exhibited excellent catalytic activity, H 2 O/SO 2 resistance, and stability. When the concentration of NO was 500 ppm, the gas spatiotemporal velocity (GHSV) was 36,000 h −1 , and the reaction temperature was 100 ℃, the NO conversion efficiency of M-MnCeO X exceeded 90.0 %. Added 200 ppm SO 2 and 3 vol% H 2 O simultaneously, the NO conversion efficiency was close to 80.0 %. By analyzing the physicochemical properties of the catalyst, M-MnCeO X had a large specific surface area, numerous acidic sites, and excellent redox properties. According to density functional theory (DFT), the NH 3 /NO adsorption energy of M-MnCeO X were −2.35 and −2.40 eV, exhibiting lower than a single MOF-derivative, promoting the adsorption of NH 3 or NO. The reaction mechanism on the M-MnCeO X catalyst followed the E-R and L-H mechanisms by In situ DRIFTS.
研究领域:
环境催化
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xiaolei Hu,Weiye Qu,Junxiao Chen,Dongrun Xu,Jing Liu,Yangyang Dong,Rui Liu,Zhen Ma,Xingfu Tang
Selective catalytic reduction (SCR) of NO x with NH 3 over V 2 O 5 -based catalysts has been widely used to control NO x emissions from power plants, but its application is largely limited in other industrial boilers because of insufficient catalytic efficiency at low temperatures. Here we resolve this problem by mechanistically designing a highly active Ce-W/TiO 2 catalyst with reactants-coupling dual catalytic sites. The results demonstrate that W and Ce are highly dispersed on the surfaces of Ce-W/TiO 2 to form dual catalytic sites, which act as acid-base pairs favorable for NH 3 and NO adsorption, respectively, thereby allowing the reaction of adsorbed NH 3 on the W site with oxidized NO species (NO 3 − ) adsorbed on the adjacent Ce site to proceed along a low-activation-energy pathway via Langmuir-Hinshelwood mechanism. Compared with Ce/TiO 2 , a W-Ce synergy gives rise to more abundant Ce 3+ on Ce-W/TiO 2 , which facilitates the activation of O 2 during SCR process, thus improving the low-temperature SCR performance. Therefore, the design of the dual catalytic sites based on the properties of reactants provides an alternative approach to developing highly active SCR catalysts.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）