ACS Catalysis
·
2016
·
IF 9.307
Xianwei Wang,Nobutaka Maeda,Alfons Baiker
Promotion of Au/TiO2 by FeOx addition is shown to result in a very strong enhancement of activity and selectivity in the NO reduction with CO. The nanocomposite Au-FeOx/TiO2 catalysts were prepared by deposition–precipitation (Au/TiO2) and subsequent impregnation (FeOx). Structural characterization of the nanocomposite catalysts using XRD, TEM, TPR, XPS, and DRIFTS revealed that they consist of titania-supported Au particles of about 4.4–4.8 nm size, which were partially covered with a thin layer of FeOx,, mainly made up of Fe2+ (FeO), in addition to a small fraction of Fe3+ (Fe2O3). In situ DRIFTS studies showed that, in comparison to Au/TiO2, on the Au-FeOx/TiO2 nanocomposites new adsorption sites were created, which led to enrichment of CO and NO molecules on the Au surface and at its interfaces with FeOx and TiO2. At the reaction temperature (250 °C), a new surface NO–CO complex, where both Fe and Au are proposed to be involved in the adsorptive interaction, was discovered. The titania-supported Au-FeOx nanocomposites considerably facilitated the formation of this complex and contributed to the striking enhancement of the catalytic performance (activity and selectivity) of the Au-based catalyst.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 10
·期 5
·1431-1443
·
IF 5.726
Zhaohui Teng,Shan Huang,Liang Fu,Heng Xu,Na Li,Qulan Zhou
In our research, rice husk ash (RHA) was employed as a catalyst support and Fe–Cu bimetallic compounds were employed as catalysts in the reduction of NO by CO. Rice husk ash contains abundant amorphous SiO2 and it would be a good catalyst support as indicated by the characterization results. Different combustion conditions were tested to obtain the appropriate rice husk ash. Characterization methods were employed to study its physical properties. The results of the catalytic activity testing experiment were highly in accordance with the characterization results. Fe2Cu1 based on rice husk ash had approximately 100% conversion rates for both NO and CO, which indicated the superiority of the rice husk ash and Fe–Cu oxides. Moreover, the O2 content, CO/NO ratio and SO2 had little influence on this new combination. This remarkable performance was due to the strong interaction between the rice husk ash and metal species. The results of our research will provide some instructions for the improvement of industrial denitrification.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS RESEARCH
·
2018
·Vol. 33
·期 16
·2414-2422
·
IF 1.495
Youchun Pan,Yuesong Shen,Qijie Jin,Shemin Zhu
A series of Ba-modified MnCeOx/TiO2 catalysts were prepared by a wet impregnation method and tested for selective catalytic reduction (SCR) of NO with NH3 at low temperature. The results showed that Ba additives obviously improved the catalytic performance of the MnCeOx/TiO2 catalyst for NH3-SCR, and the BaMnCeOx/TiO2 catalyst with 3 wt% BaO exhibited the optimal catalytic performance. Moreover, the introduction of Ba also improved the resistances toward water vapor and SO2 of catalysts. The N2 adsorption, H2-TPR, and X-ray photoelectron spectroscopy results showed that the addition of Ba increased the specific surface area, redox properties, and concentrations of surface Mn4+ and chemisorbed oxygen of catalysts. Furthermore, NH3-TPD and NO-TPD were used to investigate the absorption of NH3 and NO on the catalyst. The results revealed that although the introduction of Ba significantly promoted the adsorption of NO, it also inhibited the adsorption of NH3. Consequently, the catalytic performance of MnCeOx/TiO2 was greatly improved with the Ba additives.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2022
·
IF 4.632
Yandi Cai,Peng Yang,Qinglong Liu,Kaili Ma,Wenxin Ma,Wang Song,Qiuhui Qian,Fei Gao,Wei Tan,Lin Dong
Sulfation treatment has been widely used to promote the catalytic performance of ceria (CeO 2 ) based catalysts for the selective catalytic reduction of NO by NH 3 (NH 3 -SCR of NO). Praseodymium oxide (PrO x ), another commonly used rare earth material with similar structural properties as CeO 2 , also shows satisfactory redox properties due to the facile redox cycle of Pr 3+ ↔ Pr 4+ . In this work, gas phase sulfation treatment with varied duration was performed on PrO x at 200 °C, and the NH 3 -SCR activity of sulfated PrO x was evaluated. Based on the results of systematic characterizations (e.g., N 2 -physisorption, NH 3 oxidation , NO oxidation, in situ diffuse Fourier transform infrared spectroscopy), it is revealed that the catalytic performance of sulfated PrO x is highly dependent on the sulfation time (or the amount of sulfate species deposited on PrO x ), which has a significant impact on the competitive reaction between NH 3 oxidation and NH 3 -SCR of NO, thus determining the NH 3 -SCR activity of PrO x . This work provides new insight into tuning the interaction between PrO x surface and reactants (NO, NH 3 ) via sulfation treatment, which cam guide the design and application of PrO x based catalysts for NH 3 -SCR of NO in the future.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2021
·Vol. 13
·期 7
·1834-1846
·
IF 5.686
Ruihuan Jiang,Shaomian Liu,Liang Li,Yongjun Ji,Huifang Li,Xiangfeng Guo,Lihua Jia,Ziyi Zhong,Fabing Su
Graphical Single Ir atoms : In the CO+NO reaction, the catalyst with single-sited Ir atoms (0.28 wt %) anchored on a mesoporous WO 3 (Ir 1 /mesoporous-WO 3 ) showed much higher NO conversion and N 2 selectivity under oxygen-rich conditions than the catalysts supported with Ir nanoparticles on the same catalyst support (Ir NPs/mesoporous-WO 3 ) and on a non-mesoporous WO 3 (Ir/non-mesoporous-WO 3 ). Under oxygen-rich conditions, achieving a selective and efficient reduction of NO by CO is always challenging. Here, we report the synthesis of the catalyst consisting of single Ir atoms anchored on mesoporous WO 3 (denoted as Ir 1 /m-WO 3 ) using a facile template method followed by wet impregnation. X-ray diffraction and transmission electron microscope studies indicated that the Ir atoms were distributed uniformly on the internal surface of m-WO 3 . When tested for the reduction of NO by CO, the Ir 1 /m-WO 3 catalyst with a low Ir loading of 0.28 wt % exhibited excellent catalytic performance in the presence of 2 vol % O 2 (volume ratio of CO to O 2 being 1 : 10), achieving a NO conversion of 73 % and N 2 selectivity of 100 % at 350 °C. In particular, its turnover frequency (TOF) value reached 0.30 s −1 at 200 °C, which is six times higher than that of the catalyst with Ir nanoparticles supported on mesoporous WO 3 (0.05 s −1 ). The superior catalytic performance of Ir 1 /m-WO 3 is attributed to the formation of the isolated Ir atoms and the more newly generated Ir-WO 3 interfaces that can promote the adsorption and activation of NO, and the presence of accessible mesopores in m-WO 3 that facilitates the mass transfer of NO and CO. This study brings a new fundamental understanding of active sites in Ir-based catalysts for the CO+NO reaction and provides a new way to the design and synthesis of single-atom catalysts, especially precious metal catalysts for emissions control.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
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
ChemistrySelect
·
2025
·Vol. 10
·期 12
·e202500499
·
IF 2
Tianzhu Shao,Qi Wang,Jiahao Wei,Gonggang Sun,Xinbao Li
Graphical The study focuses on the synthesis of SCR catalysts with high activity and excellent alkali resistance. The redox performance and surface acidity of VWTi are enhanced and the atomic valencies is optimized through the doping of Ce and Bi. Therefore, the catalytic activity of the catalyst is significantly enhanced and excellent catalytic activity is maintained even after KCl poisoning. Ce-doped V 2 O 5 -WO 3 /TiO 2 (CeVWTi) and its subsequent modifications have been recognized as effective catalysts for the selective catalytic reduction of NO. Herein, CeVWTi catalysts doped with varying amounts of bismuth sulfate (Bi 2 (SO 4 ) 3 ) were synthesized and evaluated for their activity and alkali resistance. These catalysts were characterized using XPS, BET, SEM, H 2 -TPR, NH 3 -TPD, and XRD techniques. The optimal doping level of Bi 2 (SO 4 ) 3 was 1 wt.%. The NO conversion rate of the catalyst co-doped with Ce and Bi was 71.6% under the reaction conditions of 300 °C, gas hour space velocity (GHSV) = 200,000 h −1 with a gas composition of 550 ppm NO, 550 ppm NH 3 , 5.6% O 2 , and N 2 as the balance. The NO conversion efficiency of the Bi 0.01 CeVWTi catalyst was maintained at 90.7% after the addition of 1 wt.% KCl poisoning under the reaction conditions of 350 °C, GHSV = 200,000 h −1 , 550 ppm NO, 550 ppm NH 3 , 5.6% O 2 , and N 2 as the balance. Characterization showed that, despite the reduction in the specific surface area of the catalyst and some acidic sites due to Bi doping, the redox performance of Bi 0.01 CeVWTi was significantly enhanced. The excellent redox performance was maintained even after KCl poisoning.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Longcheng Zhang,Qiang Zhou,Jie Liang,Luchao Yue,Tingshuai Li,Yongsong Luo,Qian Liu,Na Li,Bo Tang,Feng Gong,Xiaodong Guo,Xuping Sun
Electrochemical reduction of NO to NH3 is of great significance for mitigating the accumulation of nitrogen oxides and producing valuable NH3. Here, we demonstrate that the CoS nanosheet with sulfur vacancies (CoS1–x) behaves as an efficient catalyst toward electrochemical NO-to-NH3 conversion. In 0.2 M Na2SO4 electrolyte, such CoS1–x displays a large NH3 yield rate (44.67 μmol cm–2 h–1) and a high Faradaic efficiency (53.62%) at −0.4 V versus the reversible hydrogen electrode, outperforming the CoS counterpart (27.02 μmol cm–2 h–1; 36.68%). Moreover, the Zn–NO battery with CoS1–x shows excellent performance with a power density of 2.06 mW cm–2 and a large NH3 yield rate of 1492.41 μg h–1 mgcat.–1. Density functional theory was performed to obtain mechanistic insights into the NO reduction over CoS1–x.
研究领域:
材料科学
·
电化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysts
·
2022
·Vol. 12
·期 5
·534
·
IF 4.501
Zhaohui Teng,Shan Huang,Na Li,Qulan Zhou
Rice husk ash (RHA) has potential as a supporter of catalysts. In this research, we studied the activity and SO2tolerance of RHA-based Fe-Cu oxide in the reduction of NO by CO. Characterization methods were employed to study the properties of the catalysts and their SO2tolerance. Activity and SO2resistance were also tested at different temperatures. We recommend two catalysts with SO2resistance ability: Fe0.67Cu0.33/RHA (the highest catalytic activity) and Fe0.8Cu0.2/RHA. The NO removal rate hardly changed with the addition of SO2and was kept at about 100%. However, the CO conversion rate decreased with increasing SO2at the lower reaction temperatures, which may be due to the formation of sulfites. Fortunately, the deactivation was reversible and can be reduced with an increase in the reaction temperature. The results of our research may help promote the application of CO-SCR.Keywords:rice husk ash;Fe-Cu catalysts;NO reduction;SO2resistance;CO-SCR
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Ji Liu,Yuan-gu Xia,Meng-fan Liu,Bin Hu,Hong-jin Zhang,Ji-hong Li,Zhen-xi Zhang,Qiang Lu
Nitrogen oxides are the major pollutants in solid fuel/waste combustion processes, which can be reduced by unburned or additive chars. The surface char–NO reaction is significantly influenced by CO 2 , whereas the impact mechanism is far from conclusive. Herein, fixed-bed experiments and computational methods were adopted to elucidate the role of CO 2 on char–NO reaction. Experimentally, CO 2 exhibited an inhibitive impact on NO reduction at 873 K but a promotive influence at 1023 K and 1173 K. According to the detection of outlet CO, characterization of char, and density function theory (DFT) calculations, CO and gasified char derived from char–CO 2 gasification are both responsible for the promotive effect at 1173 K, which offers a clear image of the gasification mechanism conjectured in previous work. More importantly, a CO 2 -mediated oxygen rearrangement (CO 2 -MOR) mechanism has been found and confirmed for the first time, which can well explain the experimental results observed at 873 K and 1023 K. The adsorbed CO 2 can intervene in the oxygen rearrangement on the char surface to alter the NO reduction behaviors. The present study offers a comprehensive insight into the roles of CO 2 in the heterogeneous reduction of NO on char surface.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Environmental Science & Engineering
·
2025
·Vol. 19
·期 3
·1-15
·
IF 6.4
Zhang Xiang,Tian Jian,Hu Tanghui,Yue Guangyong,Liu Xianlong,Zhou Wen,Liu Xiaohong,Wang Xinye
Combining pulverized coal gasifiers with cement kiln production is promising for application in low-cost and efficient NO reduction. This paper presents a pulverized coal gasifier catalytic denitration technique and investigates the homogeneous reduction (by CO and CH 4 ) and heterogeneous catalytic reduction (by coke, CaO, MgO, and Fe 2 O 3 ) of NO. A combination of Chemkin simulations and fixed-bed experiments is used to elucidate the reaction pathways and key intermediates of NO reduction by carbon-based gases. In addition, the activation energies for different catalyst combinations were analyzed via reaction kinetics. The results demonstrate that the presence of small amounts of O 2 inhibits NO reduction by CO but promotes NO reduction by CH 4 . The NCO• radical is essential for the NO reduction process, and the generation of this radical depends on the CH 4 cleavage intermediate and O• radical. CaO and Fe 2 O 3 exhibit more significant catalytic effects on NO reduction by carbon-based gases than the other catalysts tested. The presence of a small amount of O 2 in the reacting gas mixtures facilitates the NO reduction reaction. The activation energy is reduced to 1.02 kJ/mol, and the NO conversion reaches 99.80% when the catalyst is C + CaO + MgO + Fe 2 O 3 and the gas composition is CO + CH 4 + O 2 . This work provides theoretical support and data recommendations for the use of pulverized coal gasifiers for the denitrification of cement kilns.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Zhanzhi Ge,Yuesong Shen,Sasa Gu
The catalyst for selective catalytic reduction of NO x at high temperatures is significantly demanded by current gas-fired exhaust purification. In this work, the complex oxides composed of two different structures of ZrO 2 -WO 3 and WO 3 /ZrO 2 with zirconium as the main component were prepared for NH 3 -SCR of NO at high temperatures by blending method and equal volume impregnation method, respectively. Combined with XRD, NH 3 -TPD, FE-SEM, BET and in situ DRIFTS characterization, the effects of component optimization of two kinds of ZrO 2 and WO 3 complex oxides on the performance for NH 3 -SCR of NO were mainly studied. The optimal compatibility of ZrO 2 and WO 3 complex oxides was determined, and the corresponding N 2 selectivity and anti-interference ability of water vapor and SO 2 were further investigated. Results showed that the performance of ZrO 2 -WO 3 prepared by blending method for NH 3 -SCR of NO was significantly better than that of WO 3 /ZrO 2 prepared by impregnation method. The ZrO 2 -WO 3 containing 20% WO 3 has the best performance in NH 3 -SCR of NO with NO conversion higher than 90% and N 2 selectivity higher than 90% at 450–650 °C, and the performance was not affected by SO 2 , slightly affected by competitive adsorption of water vapor at 450 °C and not disturbed by water vapor above 500 °C. Further investigation showed that the NH 3 -SCR of NO over the ZrO 2 -WO 3 reaction followed both L-H and E-R mechanisms. Characterization analysis revealed that ZrO 2 -WO 3 has finer microscopic particles, larger specific surface area, higher acid amount and stronger acid strength than WO 3 /ZrO 2 .
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）