Nanoscale
·
2014
·Vol. 7
·期 6
·2568-2577
·
IF 6.739
Mingying Qiu,Sihui Zhan,Hongbing Yu,Dandan Zhu,Shengqiang Wang
Ordered mesoporous MnCo2O4 nanomaterials were successfully prepared through the nanocasting route using SBA-15 and KIT-6 as hard templates. These mesoporous nanomaterials were characterized using XRD, BET, TEM, NH3-TPD, H2-TPR, NO-TPD, XPS and DRIFT. The low temperature selective catalytic reduction (SCR) activity of NO with NH3 was investigated, which revealed that 3D-MnCo2O4 using KIT-6 as a template can totally clean all NO over a wide temperature range of 100–250 °C with a gas hourly space velocity (GHSV) of 32 000 h−1, while 2D-MnCo2O4 with SBA-15 as a template had 95% conversion rate at the same condition. 3D-MnCo2O4 showed the best performance to clean NO due to its typical three-dimensional porous structure, large specific surface area, abundant active surface oxygen species and Lewis acid sites. All the results indicate that a novel, cheap catalyst for catalytic removal of NO can be designed by controlling the morphology at the nanoscale.
研究领域:
材料科学
·
环境催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2015
·
IF 3.368
Xiaole Weng,Xiaoxia Dai,Qingshan Zeng,Yue Liu,Zhongbiao Wu
Heteropoly acids (HPAs) have been effectively utilized in selective catalytic reduction (SCR) of NO to improve the NH 3 absorption capacity and alkaline/alkali metal resistance for SCR catalysts. However, despite the promise on super-acidities, their other properties that would work on SCR process are still lack of exploration. In this study, a 12-tungstaphosphoric acid (H 3 PW 12 O 40 , HPW) was selected to modify a well-reported CeO 2 catalyst. The resulted CeO 2 /HPW catalyst was subsequently utilized for SCR of NO with excess NH 3 , which revealed a significantly promoted performance in SCR reaction. DRIFT analyses showed that the unique NO 2 absorption capacity of HPW could prevent the NO 2 being further oxidized into nitrate species and the abundant Brønsted acid sites could effectively retain the NH 3 , avoiding them being over-oxidized at evaluated temperatures. The presence of NO 2 was demonstrated able to induce a so called “fast SCR” reaction over the CeO 2 /HPW catalyst, which effectively facilitated the SCR reaction. Furthermore, we have also constructed a CeO 2 @HPW catalyst, which showed an enhanced SO 2 poisoning resistance in SCR reaction.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2022
·
IF 7.926
Shuangli He,Jinghang Ren,Peng Cao
Low-temperature selective catalytic reduction (SCR) is effective and promising for converting NO x in flue gas into N 2 , with wide application prospects. However, low-temperature denitration (DeNO x ) catalysts are susceptible to SO 2 and H 2 O poisoning. Here, we prepared a monolithic Mn-Fe-Ce/Al 2 O 3 catalyst that exhibited excellent DeNO x performances at low temperatures. At 110 °C, the NO conversion rate of the catalyst was> 90%, exhibiting excellent resistances to H 2 O and SO 2 ·H 2 O and SO 2 are introduced at the same time, the efficiency is as high as 73%. Furthermore, The catalyst has a porous structure with abundant chemisorbed oxygen spices and exposed active, the reaction pathway on the catalyst proved to be the L-H mechanism based on in situ DRIFTS. This study also explored the mechanisms of low-temperature SCR catalyst poisoning by SO 2 and H 2 O, providing insights into the effects of SO 2 and H 2 O and theoretical support for the development of poisoning-resistant low-temperature SCR catalysts.
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 JOURNAL
·
2022
·
IF 16.744
Jingyan Zhang,Peng Ji,Li Ren,Yuhong Zhao,Shiqing Li,Hao Xu,Honggen Peng,Jin-Gang Jiang,Yejun Guan,Peng Wu
The small-pore CHA -type zeolites have received intensive attentions due to their outstanding performance in both of the methanol-to-olefin (MTO) process and ammonia selective catalytic reduction of nitrogen oxides (NH 3 -SCR of NO x ) reactions. However, the costly synthesis of CHA -type aluminosilicate is a great issue for the practical application. In this study, a novel and cheap organic structure-directing agent of N,N,N -trimethylisobutylammonium hydroxide was developed and used to synthesize CHA -type zeolites (name as ECNU-25) with boric acid as the supporting agent. The Si/Al ratio in the synthetic gel could be tailored in a wide range of 50 - ∞. [Al,B]-ECNU-25 zeolite thus synthesized served as an effective catalyst for the MTO reaction. After Cu 2+ -exchange, the Cu-[Al,B]-ECNU-25 was also highly active in the NH 3 -SCR of NO x .
研究领域:
化学工程
·
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 98
·期 2
·506-515
·
IF 3.709
Cao Shuang,Zhang Haixiang,Wang Xueman,Peng Miquan,Huang Renhua,Hong Wei,Fu Hailu,Chen Xiongbo,Lin Zejian
In SCR denitrification technology, the conventional coprecipitation method has the disadvantages of high temperature and difficulty in controlling the precipitation rate. Various Ce x CuTiO 2 catalysts were synthesized using ice-melting (Ce x CuTi-Ice) and conventional coprecipitation (Ce x CuTi-Con) methods for the selective catalytic reduction (SCR) of NO with NH 3 . Ce 0.4 CuTi-Ice catalyst exhibited excellent catalytic activity among the Ce x CuTiO 2 catalysts, and 80% NO x conversion was achieved within a temperature range of 250–375 °C, exceeding that of Ce 0.4 CuTi-Con catalyst by 20%; in addition, N 2 selectivity was nearly 100%. To elucidate the release characteristics of the precursor solution during ice-melting synthesis, the changes of Cu and Ce concentrations in the solution were investigated by ICP-OES. The precursor solution was released at a slow rate via the ice-melting method, resulting in a large surface area, small crystallite sizes, and effective uniform nanoparticles with abundant active species and increased surface acidity. The promoted mechanism could be attributed to the enhanced oxidation of NO to NO 2 at low temperatures and the rapid reaction between NO species and coordinated NH 3 at high temperatures. © 2022 Society of Chemical Industry (SCI).
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
Yangyang Guo,Yang Zheng,Yue Peng,Tao Yue,Tingyu Zhu
Simultaneous removal of NO x and CO from steel sintering has attracted great attention because it is difficult to balance the catalyst reducibility and surface acidity merely using metal oxides or zeolite catalysts. In this study, a mixed CuMn-HZSM-5 catalyst was prepared via an impregnation method. The optimized sample exhibited excellent performance with 90% NO conversion and 100% CO conversion at 175 °C. The activity window of the catalyst was coincident with the actual demand of sintering flue gas control at 150-250℃. The active component CuMn suppressed the excessive Lewis acid sites on the zeolite support for NH 3 adsorption, while the reducibility of the catalyst also decreased compared with that of pure CuMn metal oxides . This synergistic effect was beneficial for the reduction of NH 3 nonselective oxidation with O 2 . In addition, both the DFT and DRIFTS results revealed that NO conversion was improved by CO introduction at low temperature, since NO could adsorb on the CO-preadsorbed sites for the reduction to N 2 via the O atoms of Mn 3c sites, i.e., adsorbed CO could also serve as a reductant to reduce NO to N 2 , which provides another reaction pathway in SCR reactions. Moreover, the NO 2 − and N 2 O 2 − species were observed in the spectra as key intermediates to oxidize CO to CO 2 , which are also the promoters for CO control.
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 & TECHNOLOGY
·
2023
·Vol. 46
·期 10
·2217-2225
·
IF 2.1
Shuangshuang Lv,Xianlong Zhang,Haoyang Dong,Shi Jin,Xinyu Wang
Manganese-antimony composite oxide catalysts were prepared for use in low-temperature selective catalytic reduction of flue gas, by adopting the strategy of passivation to regulate the valence state of the active component and control catalytic activity. Activity evaluation results found that MnSb 0.36 O y delivered 80 % NO conversion in the presence of SO 2 at 200 °C, and nearly 90 % conversion at 250 °C. Doping with Sb changed the surface micromorphology, resulting in a perforated porousness layered foam with a porous structure of tens of nanometers, which was conducive to molecular mass transfer of the reaction gas. Doping with Sb regulated the valence state of the active MnO x component, which diminished catalytic oxidation of SO 2 , thus promoting catalyst stability and limiting the toxic effect of SO 2 .
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
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2023
·
IF 7.8
Shuang Chen,YeJia Lv,Jiaxing Hong,Luman Hou,Jia Zhang,Xiaoqiao Zhang,Xiangyu Zhao,Lixin Wang,Guangren Qian
Developing a more effective catalyst for the environmental pollutant is always the pursuit of worldwide researchers. In previous reports, most works were focused on prepared catalysts, and more efforts should explore process from a precursor to the formed catalyst. In this work, V supported TiO 2 catalysts were synthesized with different V loadings, and compared in selective catalytic reduction of nitrogen oxide . For the first time, differential scanning calorimetry was used to analyze the forming enthalpy for these catalysts. As a result, turnover frequency (TOF) was decreased from 0.05 to 0.001 s −1 when the loading was increased from 0.05 to 15 mol%. At the same time, the forming enthalpy was decreased from 16.53 to 1.80 KJ·mol −1 . Spherical Aberration Corrected Transmission Electron Microscope recognized both single-atom and cluster V even at the lowest loading. What’s more, density functional theory revealed that single-atom V had a lower dehydrogenation energy (1.088–1.152 eV) than cluster V during the catalysis (1.834–1.850 eV). According to these evidences, single-atom V had bigger formation enthalpy, lower dehydrogenation energy, and larger TOF than cluster V. These results help to optimize the preparation process for an effective catalyst, which is in favor of hazardous-pollutant treatment.
研究领域:
环境科学
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催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Chenxi Wang,Gang Lv,Yunqiang Li,Ye Liu,Chonglin Song
The selective catalytic reduction of nitrogen oxides by methane (CH 4 /NO X -SCR) is a potential technique for the abatement of the NO X emissions from lean-burn GDI engines, due to the excellent thermal stability of CH 4 . This work focuses on the promotion of In/SSZ-13 catalysts by Ce modification for the CH 4 /NO X -SCR performance at high temperatures. A series of In/SSZ-13 and Ce-In/SSZ-13 catalysts were prepared using the wetness impregnation method. The effects of Ce modification on the catalytic performance were analysed in detail using the scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflectance spectrum and temperature-programmed desorption/reduction techniques. The results show that the Ce modification significantly enhances the high-temperature activity of the In/SSZ-13 catalysts for the NO X -SCR reaction, especially for the 5 wt% Ce-15 wt% In/SSZ-13 sample which has more than 75% NO X conversion at 390–700 °C. In addition, the Ce modification enhances the water vapor tolerance of the catalyst sample. The Ce modification increases not only the concentration of surface chemisorption oxygen species, but also the relative amount of InO + species which serve as the main active sites for CH 4 activation. Furthermore, the incorporation of Ce into In/SSZ-13 greatly promotes NO X adsorption on the catalyst surface. Most importantly, the Ce modification makes In species well-dispersed on the catalyst surface and thus suppresses the formation of bulk In 2 O 3 species which are more active for the CH 4 non-selective oxidation. The combination of all these effects results in the Ce-In/SSZ-13 samples with the superior catalytic activity .
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Fengyuan Liu,Junqi Li,Hong Yong Sohn,Chaoyi Chen,Jian Yang,Xudong Liu,Yuanpei Lan,Wei Zhang,Qin Wang,Li Liu
The objective of this work was to clearly elucidate the interactions on Mn-Ce interface and understand how they affect low temperature selective catalytic reduction (SCR) for NO x removal. In this work, three Mn-Ce catalysts in similar particle size and morphology with different Mn-Ce interface areas were prepared. MnO 2 @CeO 2 -F had the tightest and largest amount of Mn-Ce interfaces compared with MnO 2 @CeO 2 -P and MnO 2 -CeO 2 -M, and also exhibited the highest NO conversion degree at 100–150 °C as well as the strongest activity of Mn species and lowest generation of N 2 O. The TG-DTG, XPS and electrochemical impedance spectroscopy results proved the redox of Ce 4+ + Mn 3+ ↔ Ce 3+ + Mn 4+ on the Mn-Ce interface, and MnO 2 @CeO 2 -F had the highest Mn 4+ , Ce 3+ , O α concentrations. The results of the study on the redox reactions during the NH 3 -SCR process provided powerful evidence of the Mn 4+ /Mn 3+ and Ce 3+ /Ce 4+ recycles that are important for low temperature NH 3 -SCR process. Moreover, the Mn-Ce interface was directly proved to benefit the surface acid sites, redox ability, and activity of the adsorbed intermediates. Both the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) reaction mechanisms were observed in the SCR reaction with prepared Mn-Ce materials, where “fast SCR” can be observed with MnO 2 @CeO 2 -F. Moreover, the Mn-Ce interface also lowers the activation energy of the low-temperature SCR process, with MnO 2 @CeO 2 -F having the lowest activation energy. The results from this work offered powerful evidences for the interactions of Mn/Ce redox at the Mn-Ce interface and elucidated clear understanding of the effects of Mn-Ce redox on low-temperature SCR process, which is expected to promote the NO x removal process.
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 COMMUNICATIONS
·
2023
·
IF 3.7
Li Guo,Jialing Chen,Shaokang He,Tingyu Liang,Lijun Lu,Shenke Zheng,Xinyue Hu,Lan Yi,Xiaoqin Wu
The [Fe, Al]-FER zeolites, which are prepared from the interzeolite conversion method (from MWW to FER topology) with high Al and Fe content (Si/Al of 8–18 and Si/Fe of 11–13), exhibit excellent catalytic performances and hydrothermal tolerance for NH 3 -SCR reaction. The interzeolite conversion process can be tuned by optimizing the zeolite synthesis conditions such as synthesis gel composition, crystallization time, crystallization temperature, and adding MWW seeds. The work can provide a new strategy to synthesize high Al and Fe content zeolite with high hydrothermal stability for NO x removal.
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
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Chunlei Zhang,Guangyan Xu,Yanshuang Zhang,Chuang Chang,Miao Jiang,Luna Ruan,Min Xiao,Zidi Yan,Yunbo Yu,Hong He
Selective catalytic reduction of nitrogen oxides with methane (CH 4 -SCR) has emerged as a promising technology for mitigating exhaust emissions from natural gas vehicles, while its insufficient catalytic activity and durability are key barriers to application. In this study, novel Ce/In-CHA OXZEO catalysts were prepared, demonstrating exceptional catalytic performance and stability in the CH 4 -SCR reaction. Over these OXZEO catalysts, indium species predominantly existed in the form of InO + and In x O y within the CHA zeolite framework, while CeO 2 nanoparticles primarily resided as an external layer. During the CH 4 -SCR reaction, NO oxidation to form NO 2 and nitrate species was triggered by CeO 2 , which further enhanced the activation of CH 4 on InO + sites, thus boosting the low-temperature CH 4 -SCR process by facilitating the formation of the key intermediate CH 3 NO 2 . The synergy between InO + and CeO 2 underscores the exceptional performance and stability of the Ce/In-CHA with a low SiO 2 /Al 2 O 3 ratio in reducing NO x and CH 4 emissions.
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）