Catalysts
·
2020
·Vol. 10
·期 3
·311
·
IF 3.52
Jing Shao,Shuyuan Cheng,Zhaoxu Li,Bichun Huang
A ZSM-5 zeolite with a hierarchical pore structure was synthesized by the desilication-recrystallization method using tetraethyl ammonium hydroxide (TEAOH) and cetyltrimethylammonium bromide (CTAB) as the desilication and structure-directing agents, respectively. The MnOx/ZSM-5 catalyst was synthesized by the ethanol dispersion method and applied for the low-temperature selective catalytic reduction of NOxwith NH3. The results showed that NOxconversion of the hierarchical MnOx/ZSM-5 catalyst could reach 100% at about 120 °C and could be maintained in the temperature range of 120–240 °C with N2selectivity over 90%. Furthermore, the hierarchical MnOx/ZSM-5catalyst presented better SO2resistance performance than the traditional catalyst in the presence of 100 ppm SO2at 120 °C. XRD, SEM, TEM, XPS, BET, NH3-TPD, and TG were applied to characterize the structural properties of the MnOx/ZSM-5 catalysts. These results showed that the MnOx/ZSM-5 catalyst had micropores (0.78 nm) and mesopores (3.2 nm) leading to a larger specific surface area, which improved the mass transfer of reactants and products while reducing the formation of sulfates. The better catalytic performance over hierarchical MnOx/ZSM-5 catalyst could be attributed to the higher concentration of Mn4+and chemisorbed oxygen species and higher surface acidity. The improved SO2resistance was related to the catalyst’s hierarchical pore structure.Keywords:hierarchical pore structure;MnOx/ZSM-5;NH3-SCR;SO2resistance
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
Molecular Catalysis
·
2025
·
IF 4.9
Qiuju Qin,Chaolian Zhu,Donghai Mo,Zhengjun Chen,Lihui Dong,Bin Li,Liya Zhou
MnO x exhibits excellent low temperature activity for degradation NO x , but its poor SO 2 tolerance restrains its application. Herein, an in situ construction method for MnO x loading on Mn-doped ZrO 2 carrier with carbon (MnO x /Mn-ZrO 2 -C) derived from Mn(NO 3 ) 2 /UIO-66 by in situ doped pyrolysis–oxidation, in which Mn replaces Zr to modify the electronic structure of the ZrO 2 . The MnO x /Mn-ZrO 2 -C with abundant surface oxygen and acid sites showed excellent activity and better SO 2 resistance. A series of characterization results indicated that Mn doping modulates the electron structure of carrier ZrO 2 and enhances the interactions among MnO x , carbon, and Mn-ZrO 2 , resulting in increasing the electron cloud density around Mn and Zr, and consequently, the Mn and Zr on the MnO x /Mn-ZrO 2 -C exhibit poorer sulfiphilic. These findings emphasize the benefits of utilizing a multipronged effect to fabricate highly active and sulfur-resistant NH 3 -SCR catalysts.
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
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2013
·
IF 2.145
Wei-guo Pan,Jie-nan Hong,Rui-tang Guo,Wen-long Zhen,Hong-lei Ding,Qiang Jin,Cheng-gang Ding,Shi-yi Guo
MnO x –CuO x /TiO 2 and MnO x –CuO x /Al 2 O 3 catalysts were prepared by sol–gel method and used for low temperature selective catalytic reduction of NO with NH 3 . The results showed that MnO x –CuO x /TiO 2 had better catalytic activity and SO 2 resistance than MnO x –CuO x /Al 2 O 3 in the temperature range of 100–250 °C. The properties of the catalysts were characterized by using XRD, N 2 adsorption, temperature programmed reduction (H 2 -TPR) and temperature programmed desorption (NH 3 -TPD). It was found that the support has a great impact on the acidity of catalyst; TiO 2 and Al 2 O 3 can promote the formation of Lewis acid sites and Brönsted acid sites respectively.
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
FUEL
·
2025
·
IF 7.5
Jie Gao,Zijun Ran,Jingyu Ran,Xin Huang,Chuan Ma,Yunlin Shao
The catalysts utilized for low-temperature catalytic oxidation of Hg 0 from flue gas typically suffer from issues related to H 2 O and SO 2 poisoning. This study focused on doping modification of La 0.875 Ce 0.125 CoO 3 perovskite with promoters and conducted a thorough investigation on the H 2 O and SO 2 resistance through characterization and DFT methods. Experimental results demonstrated that the LCeCO/30 wt% ZrO 2 possessed optimal H 2 O and SO 2 resistance. Under high sulfur (1500 ppm SO 2 ) and high humidity (10 % H 2 O(g)) conditions, it maintained approximately 91 % Hg 0 removal efficiency after thermal regeneration cycles. Characterization results indicated that ZrO 2 doping facilitated the formation of three-dimensional macroporous structure and protected active Co 3+ sites on the surface. Based on DFT calculations, the H 2 O poisoning is attributed to competitive adsorption between H 2 O(g) and Hg 0 on the active sites. Also, the SO 2 poisoning occurs due to competitive adsorption of SO 2 and the toxicity of sulfates to the surface active sites. Meanwhile, ZrO 2 doping can lower the adsorption energies of H 2 O(g) and SO 2 by modifying their adsorption configuration, thus weakening the competitive adsorption of H 2 O(g) and SO 2 with Hg 0 . Overall, LCeCO/ZrO 2 is a promising Hg 0 removal catalyst with superior H 2 O and SO 2 resistance.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2019
·Vol. 9
·期 6
·519
·
IF 3.444
Jiaming Shao,Fawei Lin,Yan Li,Hairong Tang,Zhihua Wang,Peixi Liu,Guanyi Chen
NO oxidation was conducted over MnOx-CeO2catalysts, which were synthesized by the co-precipitation method. The calcination temperature and third metal doping were the main considerations. MnCe catalysts calcined at 350 °C and 450 °C attained the highest NO conversion efficiency, compared to 550 °C. XRD results suggested that the higher the calcination temperature, the higher the crystallization degree, which led to a negative effect on catalytic activity. Subsequently, Sn, Fe, Co, Cr, and Cu were separately doped into MnCe composites, but no improvement was observed for these trimetallic catalysts in NO conversion. Nevertheless, MnCeSn, MnCeFe, and MnCeCo still exhibited a desirable NO conversion efficiency, so they were tested under SO2addition together with MnCe catalyst. Among them, MnCeFe exhibited the highest NO conversion after whole poisoning testing. XPS results indicated that Fe could protect Mn and Ce metal oxides from being reduced during SO2poisoning process. Furthermore, in in-situ DRIFTS measurement, part of nitrate species maintained undestroyed on the MnCeFe catalyst surface after SO2poisoning. These characteristics reinforced that Fe dropping would achieve better performance under SO2atmosphere.Keywords:MnOx-CeO2;co-precipitation;NO oxidation;SO2resistance;metal addition
研究领域:
环境科学
·
催化化学
✓ 已验证
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
Catalysts
·
2020
·Vol. 10
·期 1
·72
·
IF 3.52
Xiaopeng Zhang,Xiangkai Han,Chengfeng Li,Xinxin Song,Hongda Zhu,Junjiang Bao,Ning Zhang,Gaohong He
Sorbent of αMnO2nanorods coating TiO2shell (denoted as αMnO2-NR@TiO2) was prepared to investigate the elemental mercury (Hg0) removal performance in the presence of SO2. Due the core-shell structure, αMnO2-NR@TiO2has a better SO2resistance when compared to αMnO2nanorods (denoted as αMnO2-NR). Kinetic studies have shown that both the sorption rates of αMnO2-NR and αMnO2-NR@TiO2, which can be described by pseudo second-order models and SO2treatment, did not change the kinetic models for both the two catalysts. In contrast, X-ray photoelectron spectroscopy (XPS) results showed that, after reaction in the presence of SO2, S concentration on αMnO2-NR@TiO2surface is lower than on αMnO2-NR surface, which demonstrated that TiO2shell could effectively inhibit the SO2diffusion onto MnO2surface. Thermogravimetry-differential thermosgravimetry (TG-DTG) results further pointed that SO2mainly react with TiO2forming Ti(SO4)O in αMnO2-NR@TiO2, which will protect Mn from being deactivated by SO2. These results were the reason for the better SO2resistance of αMnO2-NR@TiO2.Keywords:core-shell structure;αMnO2nanorods;elemental mercury removal;SO2resistance
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2022
·
IF 6.47
Longyi Xue,Ninghan Wei,Cheng Zhao,Xiaomei Hu,Junge Yun,Zimo Chen,Zhiyi Deng,Zhihang Chen
CeO 2 as selective catalytic reduction (SCR) catalyst has attracted wide attention due to its abundant surface acidity and excellent oxygen storage/release capacity. However, its further implication was hindered owing to insufficient catalytic activity and SO 2 resistance. Novel Cr doped CeO x catalysts were synthesized by solid phase method and used for NH 3 -SCR of NO x at middle-low temperature. The effect of Cr addition on the SCR performance and physicochemical properties of CeO 2 catalyst was investigated by activity test and characterizations. Among the tested catalysts, Cr(0.4)-CeO x catalyst exhibited excellent NO x removal efficiency, with >90% NO conversion within 180–300 °C, 100% NO conversion at 220 °C and outstanding SO 2 resistance at 240 °C under 100 or 600 ppm SO 2 . The characterizations results revealed that Cr modified CrCeO x catalyst could effectively increase BET surface area, pore volume, surface acidity and redox capacity. In situ DRIFTS indicated that SCR reactions over Cr(0.4)-CeO x catalyst followed Eley-Rideal mechanism and active –NH 2 was the major intermediate species. After sulfuration, Cr(0.4)-CeO x still exhibited excellent SCR activity due to the increase of Cr 6+ , Ce 3+ and O α concentration and the formation of Cr–O–Ce bond, new Brønsted acid site and more crystallized Cr 2 O 3 .
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
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2021
·
IF 3.995
Li Huang,Yiqing Zeng,Yibo Gao,Hu Wang,Yuhao Zong,Zhengfeng Chang,Shule Zhang,Pei Han,Yang Yu
The oxidation of SO 2 into SO 3 promote the formation of NH 4 HSO 4 (ABS), which can cover surface active sites catalyst, and then leading to the decrease of NH 3 -SCR De-NO x activity. In this work, phosphorus species were loaded on the V 2 O 5 -MoO 3 /TiO 2 De-NO x catalyst to enhance its SO 2 resistance via inhibiting the SO 2 /SO 3 conversion. XRD and N 2 -adsorption results showed that phosphorus has little impact on the structure and pore property of the catalyst. The results of XPS , H 2 -TPR, and NH 3 -TPD analyses illustrated that suitable amount of phosphorus (1%) increases the content of polymeric vanadate and chemisorbed oxygen (O α ) of the catalyst, which is benefit to the SCR process. Phosphorus species decreases the SO 2 absorbability and SO 2 oxidation activity of V-Mo-P/Ti catalysts, thus it exhibits higher NH 3 -SCR activity than that of the P-free catalyst at presence of SO 2 due to the lower SO 2 /SO 3 conversion and fewer amount of NH 4 HSO 4 deposition.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 28
·期 46
·65487-65498
·
IF 4.223
Zhou
Jiacheng,Shen Qicheng,Yang Jie,Tariq Muhammad,Sun Wei,Cao Limei,Yang Ji
Co 3 O 4 is a promising Hg 0 removal catalyst for industrial application. Operating temperature and low sulfur resistance are two of the main problems that hinder its industrial application in Hg 0 removal. Herein, a metal-organic framework (Co-BDC) was introduced as a sacrificial template to obtain the catalyst nano-sized Co 3 O 4 @C by calcination. Part of the organic ligands is carbonized during the calcination. Carbon wrapped Co 3 O 4 and reduced metal agglomeration. The optimal Hg 0 removal temperature of the existing cobalt oxide catalysts was always around 150 °C, but H 2 -TPR showed that the oxygen atoms on the Co 3 O 4 @C were more active than those on Co 3 O 4 , causing the Hg 0 removal temperature window of Co 3 O 4 @C to shift to lower temperatures. The Hg 0 removal efficiency of Co 3 O 4 @C could reach almost 100% even at 25 °C. In the meanwhile, Co 3 O 4 @C also showed a strong SO 2 resistance at ambient temperature. Experimental results and characterization proved that SO 2 did not compete with Hg 0 on the surface of Co 3 O 4 at low temperatures. On the contrary, it participated in the oxidation of Hg 0 . This is a great improvement for Co 3 O 4 catalyst in Hg 0 removal. It reduces the restrictions on the application of Co 3 O 4 in Hg 0 removal. Co 3 O 4 @C shows considerable potential as an Hg 0 removal catalyst.
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
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Zhong-yi Wang,Rui-tang Guo,Zhen-zhen Guan,Xu Shi,Wei-guo Pan,Zai-guo Fu,Hao Qin,Xing-yu Liu
A sequence of Cr-modified CeZr 2 O x catalysts were synthesized through the co-precipitation way and applied in selective catalytic reduction (SCR) of NO x with ammonia. The optimal catalyst (Cr 1 CeZr 2 O x ) exhibited the excellent NH 3 -SCR activity and high SO 2 resistance. From the characterization results, Cr species in Cr 1 CeZr 2 O x could suppress the formation of ZrO 2 crystals, which could also contribute to stronger surface acidity and reducibility . Besides, more Ce 3+ and surface adsorbed oxygen species were observed on Cr 1 CeZr 2 O x catalyst. On the basis of in situ DRIFT experiments, it could be confirmed that the NH 3 -SCR process on Cr 1 CeZr 2 O x was promoted through Langmuir-Hinshelwood (L-H) mechanism. Besides, the improved NO oxidation and more ad-NO x and ad-NH 3 also played a vital role for the superior low-temperature SCR activity of Cr 1 CeZr 2 O x .
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jiaqi Wu,Jian Tian,Weijian Zhou,Siyu Liu,Daohua Sun
In the catalytic combustion of volatile organic compounds (VOCs) using noble metal catalysts, resistance to SO 2 poisoning poses a significant challenge. To tackle this problem, Pt nanoparticle catalysts encapsulated in hollow carbon spheres (Pt@HCS catalysts) are synthesized. The Pt@HCS catalyst exhibits excellent benzene conversion, achieving 100 % conversion at 165 °C under an air velocity of 20,000 mL/(g h). Compared to the conventional supported Pt/HCS catalyst, the Pt@HCS catalyst demonstrates a significantly improved resistance to SO 2 poisoning. In the presence of 25 ppm SO 2 , the Pt@HCS catalyst is capable of maintaining a 100 % benzene conversion rate within 24 h, whereas the conversion rate of Pt/HCS drops substantially to approximately 52 %. It is confirmed that the hollow porous structure provided a larger specific surface area and more adsorption sites, thereby facilitating benzene oxidation. More importantly, in situ DRIFTS reveals that the adsorption and desorption processes of SO 2 , along with the generation of substances like SO 3 2− , are strictly limited to the surface of the carbon shell, thereby preserving the integrity of the internal reaction environment. Multiple characterizations combined with density functional theory (DFT) have demonstrated a unique separation effect over Pt@HCS, whereby the hydroxyl groups on the carbon shell preferentially capture SO 2 while allowing benzene molecules to enter the cavities of the catalyst. In this way, any internal ingress of SO 2 and competition with benzene for Pt adsorption is effectively avoided. This study offers a potential solution to enhance the performance of noble metal catalysts in the presence of sulfur compounds.
研究领域:
环境科学
·
材料科学
·
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）