Molecular Catalysis
·
2021
·
IF 5.062
Yu Guan,Yinhe Liu,Qiang Lv,Bo Wang
The selective catalytic reduction of nitrogen oxides (NO x ) by carbon monoxide (CO-SCR) is a promising way to deal with exhaust gasses. And Effective redox cycle and NO dissociation ability are crucial factors for catalytic reduction of NO x . Herein, Fe decorated CeO 2 microsphere catalysts with surface oxygen defect were synthesized by solvothermal and calcination method. Among all catalysts, 0.5Fe-CeO 2 sample showed excellent catalytic performance with efficiency near 96% for NO reduction under the condition of 550 ppmv NO, 1200 ppmv CO, and 40,000 h − 1 of GHSV. It was found that Fe doping could efficiently regulate Ce 4+ /Ce 3+ redox couple and oxygen vacancy for catalytic activity. XRD, Raman, XPS, EPR and H 2 -TPR etc. were employed to explore the physicochemical properties of samples. The results showed that Fe had been incorporated into CeO 2 by XRD, and the results of Raman spectrum and XPS indicated that Ce 4+ /Ce 3+ redox couple existed in 0.5Fe-CeO 2 catalyst. Furthermore, the H 2 -TPR spectrum displayed the formation of oxygen vacancy in the samples. N 2 adsorption-desorption isotherms indicated that the doping of Fe could enlarge the specific surface area, pore volume and pore dimeter of the samples, and thus greatly enhanced the NO adsorption and further NO catalytic reduction on catalysts. In addition, other characterization of physicochemical properties and density functional theory (DFT) calculation were performed to reveal the mechanism of NO + CO reaction. As a result, a mechanism was proposed to elucidate highly efficient NO reduction over the catalysts of Fe decorated CeO 2 microspheres. Finally, the synergistic effects of redox center and oxygen vacancy on catalytic activity enhancement were revealed. This work provides a promising way to the design of efficient catalysts for NO reduction.
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
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Hailong Li,Jiexia Zhao,Weilin Zhang,Jianping Yang,Jun Wang,Mingguang Zhang,Zequn Yang,Liqing Li,Kaimin Shih
Manganese oxide/titanium dioxide (MnO x /TiO 2 , or MnTi) catalyst prepared by an ultrasound-assisted impregnation method was employed for simultaneous nitrogen oxide (NO) reduction and elemental mercury (Hg 0 ) oxidation under a simulated selective catalytic reduction (SCR) atmosphere. An NO reduction rate of 83% and Hg 0 oxidation rate of 96% were simultaneously achieved at a relatively low temperature of 200 °C. Ammonia (NH 3 ) as a reducing agent in the NO-SCR process was systematically investigated for its effect on Hg 0 oxidation. The results showed that NH 3 inhibited Hg 0 oxidation over the low-temperature MnTi catalysis process. In the presence of NH 3 , competitive adsorption between NH 3 and Hg 0 on the MnTi catalyst was partly responsible for the weakening Hg 0 oxidation. NH 3 consumed surface oxygen (O 2 ) on the MnTi catalyst, which also resulted in lower Hg 0 oxidation rate, especially in the absence of gas phase O 2 in the flue gas . More importantly, oxidized mercury was reduced by NH 3 to form Hg 0 with the aid of NO, i.e., the combined presence of NO and NH 3 induced the reduction of oxidized mercury, and hence partially offset Hg 0 oxidation. The effects of individual SCR gases, such as O 2 , NO, and the combinations, on Hg 0 oxidation were also elaborated.
研究领域:
环境科学
·
催化化学
·
大气污染控制
·
化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jiangxiao Qiao,Jinxin Gan,Fei Gao,Xiangsen Xu,Jiesong Tan,Yiqing Zeng,Feng Zhang,Feng Han,Zhaoxiang Zhong,Weihong Xing
Synergistic removal of nitrogen oxides (NOx) and particulate matter (PM) can be achieved using multifunctional catalytic membranes. In this work, CePO4 nanorods were loaded on the pore surfaces of SiC membranes to construct the CePO4/SiC-X catalytic membranes. The stacked nanorod structure of the CePO4 catalyst layer facilitates the diffusion of gases to the catalyst surface during reactions. Owing to the high specific surface area, rich surface acidity, and strong redox capacity, the CePO4/SiC-400 catalytic membrane exhibits the best ammonia-selective catalytic reduction (NH3–SCR) denitration activity, achieving >90% NO conversion at a temperature of 250–380 °C and negligible N2O byproduct. In addition, the CePO4/SiC-400 catalytic membrane demonstrates excellent H2O and SO2 resistance. The performance of dust filtration and simultaneous dust filtration and denitration at 250–350 °C proposed that the dust rejection efficiency reached more than 99% at various conditions, and the dust filtration process did not affect the NH3–SCR performance of the CePO4/SiC-400 catalytic membrane. From the above results, the CePO4/SiC-400 catalytic membrane presents a broad application prospect in the simultaneous dust removal and denitration of high-temperature flue gas.
研究领域:
环境科学
·
催化材料
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jiahao Chen,Bin Wang,Kai Yuan,Yutang Kang,Shasha Feng,Feng Han,Hongmiao Wu,Rongfei Zhou,Zhaoxiang Zhong,Yiqun Fan,Weihong Xing
The SiC catalytic membrane combining dust removal and denitration can realize the efficacious treatment of atmospheric pollutants. Unfortunately, a large amount of SiO 2 , formed by the partial oxidation of SiC at a high temperature, results in the decreased chemical resistance of SiC catalytic membrane. In addition, the complicated preparation processes and susceptible to loss of catalytic components under harsh conditions restrict the industrial application of SiC catalytic membranes. Here, the Cu-SAPO-34(D)/SiC catalytic membranes were directly prepared via a facile one-pot hydrothermal synthesis method, which ingeniously utilized the generated SiO 2 as a Si source to participate in the growth of Cu-SAPO-34 zeolites. Excellent binding strength and chemical resistance were simultaneously realized for the SiC catalytic membranes. As a comparison, a Cu-SAPO-34(I)/SiC catalytic membrane was fabricated via the conventional two-step ion-exchange method. The 0.2 Cu-SAPO-34(D)/SiC (Cu molar ratio of 0.2) achieved the best NH 3 -SCR performance among the prepared catalytic membranes for its highly active copper and oxygen species, abundant Lewis acid sites and remarkable redox capacity. When implementing the simultaneous removal of NO and PM, the 0.2 Cu-SAPO-34(D)/SiC catalytic membrane achieved a high NO degradation performance of 98% from 200 to 280 °C, coupled with an excellent PM 0.3 (model dust with average size of 300 nm) filtration performance of 99.99%. These results were better than those of the Cu-SAPO-34(I)/SiC catalytic membrane (92% for NO degradation and 99.98% for PM 0.3 filtration). The one-pot in situ synthesis of Cu-SAPO-34(D)/SiC catalytic membrane with enhanced binding strength and chemical resistance provides a novel strategy for preparation of high-performance SiC catalytic membrane with double benefits.
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
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
Catalysis Science & Technology
·
2016
·Vol. 6
·期 24
·8516-8524
·
IF 5.287
Lei Huang,Kaiwen Zha,Supawadee Namuangruk,Anchalee Junkaew,Xin Zhao,Hongrui Li,Liyi Shi,Dengsong Zhang
Surface engineering of TiO2 is significant in the SCR reaction and worth studying. In a previous study, we found that TiO2 nanosheets (TiO2-NS) with the (001) plane exhibited a much better SCR performance than TiO2 nanoparticles (TiO2-NP) with the (101) plane. In this work, in situ DRIFTS and DFT calculations were applied to address the promotional effect of the (001) plane of TiO2-NS in the SCR reaction. The behavior of adsorption and desorption of NOx and NH3 on the two surfaces was studied. It was found that NH3 adsorbed on both TiO2-NS and TiO2-NP was in the form of NH3(g) on the Lewis acid sites. NOx on TiO2-NP were mainly trans-(NO)2 and N2O4 which were non-reactive. Differently, NO on TiO2-NS was mainly in the form of NO2 which was probably due to the high energy and abundant active oxygen species of the (001) facet. The formed NO2 could trigger the subsequent ‘fast SCR’ reaction thereafter promoting the activity. Therefore, TiO2-NS with more (001) facets had better SCR activity than TiO2-NP with the exposed (101) facet.
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
CHINESE JOURNAL OF CATALYSIS
·
2015
·
IF 1.964
Xin Zhao,Lei Huang,Hongrui Li,Hang Hu,Jin Han,Liyi Shi,Dengsong Zhang
Different transition metals were used to modify V 2 O 5 -based catalysts (M-V, M = Cu, Fe, Mn, Co) on TiO 2 via impregnation, for the selective reduction of NO with NH 3 . The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO 2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N 2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO 2 showed the highest activity and N 2 selectivity at 225–375 °C. The results of X-ray photoelectron spectroscopy, NH 3 -temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO 2 /H 2 O durability of Cu-V/TiO 2 make it a candidate to be a NO x removal catalyst for stationary flue gas.
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
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Jingang Wang,Jianbo Zhang,Cheng Xing,Taosheng Jin,Jinpeng Liu,Meiting Ju,Xuejiao Tang
Phosphorus (P) poisoning of NH 3 -SCR catalysts is inevitable in application of NO x abatement of diesel exhaust. The distinct effects on Cu-SSZ-13 of P from different precursors (H 3 PO 4 and (NH 4 ) 2 HPO 4 ) were figured out and the mechanism was further investigated. P-poisoned Cu-SSZ-13 (Si/Al = 6) catalysts were prepared and characterized using N 2 adsorption, X-ray powder diffraction (XRD), scanning electron microscope with energy-dispersive X-ray spectroscopy mapping (SEM-EDX), ammonia temperature-programmed desorption (NH 3 -TPD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature programmed reduction (H 2 -TPR), electron paramagnetic resonance (EPR) and 27 Al solid-state magic angle spinning nuclear magnetic resonance spectroscopies ( 27 Al NMR). Significant enhancement of high-temperature activities (400–600 °C) were observed for the catalysts with P loading of 0.3–0.9 wt%, since the appropriate incorporation enabled to bind P atoms to CuO x in remained framework. However, the high P content of 1.5 wt% resulted in a detrimental effect on framework to induce the accumulation of Cu species. Interestingly, the dominant P from H 3 PO 4 was inclined to directly attack the framework Al leading to more severe dealumination, while the P from (NH 4 ) 2 HPO 4 interacted with Cu 2+ to form copper phosphate with more Cu 2+ migrating to the surface of the catalyst which promoted the NO x conversation at each active site resulting in the low-temperature catalytic activity unchanged. So, control of the P/Cu and form of P is capable of preventing P poisoning and unlocks the potential of Cu-SSZ-13 in exhaust treatment.
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
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Feng Xiaoxin,Zhou Tingting,Liu Zhigang,Yang Lirong,Wang Chunmei,Xie Yuantao,Li Qinglong
Iron oxide red (IOR) is a kind of byproduct from spray pyrolysis treatment process of pickling waste liquid. In this project, manganese oxide and manganese cerium co-oxide were loaded onto the surface of IORto prepare IOR supported manganese oxide (Mn x /IOR) and IOR supported manganese-cerium co-oxide (Mnx-Cey/IOR) catalysts by a simple combustion method. Low temperature NH3-selective catalytic reduction (NH3-SCR) denitrification properties of the synthetic catalysts were studied. XRD , SEM, EDS , TEM, BET, XPS, H 2 -TPR and NH 3 -TPD were used to characterize the physiochemical properties of the catalysts. The results show that during the combustion process for preparing Mnx/IOR catalyst, MnO x , almost all in amorphous phase, can be well distributed on the surface of the IOR carrier. The NO x conversions of Mn x /IOR catalyst gradually increase with the increase of MnO x loading amount within a specific working temperature range (<200 °C). When MnO x loading amount x is 0.43, the NO x conversion is up to 85% at most. The low temperature NH 3 -SCR activity of Mn x /IOR catalyst can be enhanced remarkably by introducing cerium . The NO x conversions of Mn 0.43 -Ce y /IOR catalyst at the operating temperature range (<200 °C) increase steadily with the cerium adding amount increasing. All the Mn 0.43 -Ce y /IOR catalysts show excellent denitrification efficiency (more than 90%) at about 160 °C. Compared with Mn 0.43 /IOR catalyst, Mn 0.43 -Ce 0.1 /IOR shows excellent denitrification performance and application prospect because of its higher manganese valence state, enhanced redox capacity, larger specific surface area, and significantly improved surface acidity and anti-SO 2 poisoning ability.
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
RSC Advances
·
2017
·Vol. 7
·期 60
·37787-37796
·
IF 3.108
Xuesong Liu,Xiaodong Wu,Duan Weng,Zhichun Si,Rui Ran
Cu/SAPO-34 catalysts were prepared by wet impregnation and ion-exchange methods, and both the catalysts were hydrothermally treated at 750 °C in 10 vol% H2O/air for 24 h. Subsequently, the as-received and hydrothermally treated catalysts were exposed to a sulfur poisoning treatment at 350 °C in 100 ppm SO2/10 vol% H2O/air for 24 h and examined for NOx conversion. Sulfur poisoning considerably decreased the NOx conversion efficiency of the catalysts at low temperatures. In contrast, it improved the high-temperature selective catalytic reduction (SCR) activities of the as-received catalysts. The ion-exchange-prepared catalysts displayed higher sulfur tolerance than the impregnation-prepared catalysts at 150–350 °C. The electron paramagnetic resonance, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy and H2-temperature-programmed reduction results showed that sulfur poisoning significantly influenced the migration of the copper species and thereby the amount of active isolated Cu2+. More dispersed CuSO4 was produced on the ion-exchange-prepared catalysts than on the impregnation-prepared catalysts after sulfur poisoning. The dispersed CuSO4 showed considerably higher SCR activity than the crystalline CuSO4. Both the dispersed CuSO4 and remaining isolated Cu2+ determined the low-temperature SCR behavior of the sulfur-poisoned catalysts.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
MATERIALS & DESIGN
·
2017
·
IF 4.364
Zijian Su,Yuanbo Zhang,Benlai Han,Bingbing Liu,Manman Lu,Zhiwei Peng,Guanghui Li,Tao Jiang
Chemical vapor transport (CVT) process is a simple and efficient method for synthesizing nano-SnO products, and previous references reveal that the CVT process is characterized as high temperature and long synthesis time. Our previous studies indicated that SnO 2 was easily reduced to solid-state SnO and then volatilized as gaseous SnO under certain CO-CO 2 atmosphere, so that a novel CVT process under CO-CO 2 atmosphere was proposed in the present work. The nano-SnOs synthesized by the CVT under 15 vol% CO/(CO + CO 2 ) atmosphere were characterized using XRD , SEM, TEM, XPS , etc. The results showed that tetragonal structure nano-SnO diskette and sphere with uniform granularity of 50–100 nm were obtained with high purity. During the CVT process, CO-CO 2 mixed gases could reduce SnO 2 to SnO and act as a CVT medium to take away the newly formed gaseous SnO, resulting in the decrease of the partial pressure of SnO. In addition, the nano-SnOs could enhance the SCR deNOx activity of activated carbon (AC), and both the reaction temperature window of AC and the NO conversion were increased if the AC was coated by nano-SnOs.
研究领域:
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）