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Effect of different acid anions on highly efficient Ce-based catalysts for selective catalytic reductionof NO with NH3

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1399-1411 doi: 10.1007/s11705-023-2345-5

摘要： Three kinds of Ce-based catalysts (CePO4, CeVO4, Ce2(SO4)3) were synthesized and used for the selective catalytic reduction (SCR) of NO by NH3. NH3-SCR performances were conducted in the temperature range of 80 to 400 °C. The catalytic efficiencies of the three catalysts are as follow: CePO4 > CeVO4 > Ce2(SO4)3, which is in agreement with their abilities of NH3 adsorption capacities. The highest NO conversion rate of CePO4 could reach about 95%, and the catalyst had more than 90% NO conversion rate between 260 and 320 °C. The effect of PO43–, VO43– and SO42– on NH3-SCR performances of Ce-based catalysts was systematically investigated by the X-ray photoelectron spectroscopy analysis, NH3 temperature programmed desorption, H2 temperature programmed reduction and field emission scanning electron microscopy tests. The key factors that can enhance the SCR are the existence of Ce4+, large NH3 adsorption capacity, high and early H2 consumptions, and suitable microstructures for gas adsorption. Finally, CePO4 and CeVO4 catalysts also exhibited relatively strong tolerance of SO2, and the upward trend about 8% was detected due to the sulfation enhancement by SO2 for Ce2(SO4)3.

关键词： CePO4     CeVO4     Ce2(SO4)3     selective catalytic reduction     NO removal    

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Low-temperature selective catalytic reduction of NO with NH based on MnO-CeO/ACFN

SHEN Boxiong, LIU Ting, SHI Zhanliang, SHI Jianwei, YANG Tingting, ZHAO Ning

《化学科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 325-329 doi: 10.1007/s11705-008-0053-9

摘要： MnO-CeO/ACFN were prepared by the impregnation method and used as catalyst for selective catalytic reduction of NO with NH at 80°C–150°C. The catalyst was characterized by N-BET, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The fraction of the mesopore and the oxygen functional groups on the surface of activated carbon fiber (ACF) increased after the treatment with nitric acid, which was favorable to improve the catalytic activities of MnO-CeO/ACFN. The experimental results show that the conversion of NO is nearly 100% in the range 100°C–150°C under the optimal preparation conditions of MnO-CeO/ACFN. In addition, the effects of a series of performance parameters, including initial NH concentration, NO concentration and O concentration, on the conversion of NO were studied.

关键词： preparation     conversion     favorable     selective catalytic     MnO-CeO/ACFN    

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On the monolayer dispersion behavior of Co3O4 on HZSM-5 support: designing applicablecatalysts for selective catalytic reduction of nitrogen oxides by ammonia

《化学科学与工程前沿（英文）》 2023年 第17卷 第11期   页码 1741-1754 doi: 10.1007/s11705-023-2332-x

摘要： Based on monolayer dispersion theory, Co3O4/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia. Co3O4 can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m–2, equaling to a weight percentage around 4.5%. It has been revealed that the quantities of surface active oxygen (O2–) and acid sites are crucial for the reaction, which can adsorb and activate NOx and NH3 reactants effectively. Below the monolayer dispersion threshold, Co3O4 is finely dispersed as sub-monolayers or monolayers and in an amorphous state, which is favorable to generate the two kinds of active sites, hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide. However, the formation of crystalline Co3O4 above the capacity is harmful to the reaction performance. 4% Co3O4/ZSM-5, the catalyst close to the monolayer dispersion capacity, possesses the most abundant active O2– species and acidic sites, thereby demonstrating the best reaction performance in all the samples. It is proposed the optimal Co3O4/ZSM-5 catalyst can be prepared by loading the capacity amount of Co3O4 onto HZSM-5 support.

关键词： Co3O4/ZSM-5     NOx-SCR by NH3     monolayer dispersion threshold effect     surface acid sites     surface active O2– anions    

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Promotion of transition metal oxides on the NH

Weiman Li, Haidi Liu, Yunfa Chen

《环境科学与工程前沿（英文）》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0914-x

摘要： Manganese and chromium oxides promote the NH -SCR activity of Zr-Ce mixed oxide. Cr-Zr-Ce mixed oxide exhibited>80% NO conversion at a wide temperature window. More acid sites and higher reducibility may responsible for the high SCR ability. Chromium oxide and manganese oxide promoted ZrO -CeO catalysts were prepared by a homogeneous precipitation method for the selective catalytic reduction of NO with NH . A series of characterization including X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Brunauer–Emmett–Teller (BET) surface area analysis, H temperature-programmed reduction (H -TPR), and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the physicochemical properties on NH -SCR activity. Cr-Zr-Ce and Mn-Zr-Ce catalysts are much more active than ZrO -CeO binary oxide for the low temperature NH -SCR, mainly because of the high specific surface area, more surface oxygen species, improved reducibility derived from synergistic effect among different elements. Mn-Zr-Ce catalyst exhibited high tolerance to SO and H O. Cr-Zr-Ce mixed oxide exhibited>80% NO conversion at a wide temperature window of 100°C–300°C. DRIFT studies showed that the addition of Cr is beneficial to the formation of Bronsted acid sites and prevents the formation of stable nitrate species because of the presence of Cr . The present mixed oxide can be a candidate for the low temperature abatement of NO .

关键词： NH3-selective catalytic reduction     NOx     Low temperature     Cr-Zr-Ce    

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NiBO (B = Mn or Co) catalysts for NH-SCR of NO at low-temperature in microwave field

《环境科学与工程前沿（英文）》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1696-y

摘要：

● Microwave-assisted catalytic NH3-SCR reaction over spinel oxides is carried out.

关键词： Microwave field     Spinel oxides     NOx     Selective catalytic reduction    

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Characterization and performance of V

Caiting LI, Qun LI, Pei LU, Huafei CUI, Guangming ZENG

《环境科学与工程前沿（英文）》 2012年 第6卷 第2期   页码 156-161 doi: 10.1007/s11783-010-0295-x

摘要： A series of CeO supported V O catalysts with various loadings were prepared with different calcination temperatures by the incipient impregnation. The catalysts were evaluated for low temperature selective catalytic reduction (SCR) of NO with ammonia (NH ). The effects of O and SO on catalytic activity were also studied. The catalysts were characterized by specific surface areas (S ) and X–ray diffraction (XRD) methods. The experimental results showed that NO conversion changed significantly with the different V O loading and calcination temperature. With the V O loading increasing from 0 to 10 wt%, NO conversion increased significantly, but decreased at higher loading. The optimum calcination temperature was 400°C. The best catalyst yielded above 80% NO conversion in the reaction temperature range of 160°C–300°C. The formation of CeVO on the surface of catalysts caused the decrease of redox ability.

关键词： V2O5/CeO2 catalysts     NH3-SCR (selective catalytic reduction)     the incipient impregnation     low temperatures    

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Multi-stage ammonia production for sorption selective catalytic reduction of NO

Chen ZHANG, Guoliang AN, Liwei WANG, Shaofei WU

《能源前沿（英文）》 2022年 第16卷 第5期   页码 840-851 doi: 10.1007/s11708-021-0797-1

摘要： Sorption selective catalytic reduction of nitrogen oxides (NOx) (sorption-SCR) has ever been proposed for replacing commercial urea selective catalytic reduction of NOx (urea-SCR), while only the single-stage sorption cycle is hitherto adopted for sorption-SCR. Herein, various multi-stage ammonia production cycles is built to solve the problem of relative high starting temperature with ammonia transfer (AT) unit and help detect the remaining ammonia in ammonia storage and delivery system (ASDS) with ammonia warning (AW) unit. Except for the single-stage ammonia production cycle with MnCl2, other sorption-SCR strategies all present overwhelming advantages over urea-SCR considering the much higher NOx conversion driven by the heat source lower than 100°C and better matching characteristics with low-temperature catalysts. Furthermore, the required mass of sorbent for each type of sorption-SCR is less than half of the mass of AdBlue for urea-SCR. Therefore, the multifunctional multi-stage sorption-SCR can realize compact and renewable ammonia storage and delivery with low thermal energy consumption and high NOx conversion, which brings a bright potential for efficient commercial de-NOx technology.

关键词： selective catalytic reduction (SCR)     nitrogen oxides (NOx)     ammonia     composite sorbent     chemisorption    

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Effects of support acidity on the reaction mechanisms of selective catalytic reduction of NO by CH

Shicheng XU, Junhua LI, Dong YANG, Jiming HAO

《环境科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 186-193 doi: 10.1007/s11783-009-0016-5

摘要： The reaction mechanisms of selective catalytic reduction (SCR) of nitric oxide (NO) by methane (CH ) over solid superacid-based catalysts were proposed and testified by DRIFTS studies on transient reaction as well as by kinetic models. Catalysts derived from different supports would lead to different reaction pathways, and the acidity of solid superacid played an important role in determining the reaction mechanisms and the catalytic activities. Higher ratios of Br?nsted acid sites to Lewis acid sites would lead to stronger oxidation of methane and then could facilitate the step of methane activation. Strong Br?nsted acid sites would not necessarily lead to better catalytic performance, however, since the active surface NO species and the corresponding reaction routes were determined by the overall acidity strength of the support. The reaction routes where NO moiety was engaged as an important intermediate involved moderate oxidation of methane, the rate of which could determine the overall activity. The reaction involving NO moiety was likely to be determined by the step of reduction of NO. Therefore, to enhance the SCR activity of solid superacid catalysts, reactions between appropriate couples of active NO species and activated hydrocarbon intermediates should be realized by modification of the support acidity.

关键词： selective catalytic reduction (SCR)     nitric oxide (NO)     methane     support acidity     Br?nsted acid sites     NOy species    

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Design and operational considerations for selective catalytic reduction technologies at coal-fired boilers

Jeremy J. SCHREIFELS, Shuxiao WANG, Jiming HAO

《能源前沿（英文）》 2012年 第6卷 第1期   页码 98-105 doi: 10.1007/s11708-012-0171-4

摘要： By the end of 2010, China had approximately 650 GW of coal-fired electric generating capacity producing almost 75% of the country’s total electricity generation. As a result of the heavy reliance on coal for electricity generation, emissions of air pollutants, such as nitrogen oxides (NO ), are increasing. To address these growing emissions, the Ministry of Environmental Protection (MEP) has introduced new NO emission control policies to encourage the installation of selective catalytic reduction (SCR) technologies on a large number of coal-fired electric power plants. There is, however, limited experience with SCR in China. It is therefore useful to explore the lessons from the use of SCR technologies in other countries. This paper provides an overview of SCR technology performance at coal-fired electric power plants demonstrating emission removal rates between 65% and 92%. It also reviews the design and operational challenges that, if not addressed, can reduce the reliability, performance, and cost-effectiveness of SCR technologies. These challenges include heterogeneous flue gas conditions, catalyst degradation, ammonia slip, sulfur trioxide (SO ) formation, and fouling and corrosion of plant equipment. As China and the rest of the world work to reduce greenhouse gas emissions, carbon dioxide (CO ) emissions from parasitic load and urea-to-ammonia conversion may also become more important. If these challenges are properly addressed, SCR can reliably and effectively remove up to 90% of NO emissions at coal-fired power plants.

关键词： nitrogen oxides (NOx)     coal     selective catalytic reduction (SCR)     air pollution control    

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Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selectivecatalytic reduction of NO

《环境科学与工程前沿（英文）》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1337-7

摘要：

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst.

关键词： NOx     Selective catalytic reduction     Iron-based catalyst     Red mud     Monolithic catalyst     Activated carbon    

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Metal-organic framework loaded manganese oxides as efficient catalysts for low-temperature selectivecatalytic reduction of NO with NH

Minhua Zhang, Baojuan Huang, Haoxi Jiang, Yifei Chen

《化学科学与工程前沿（英文）》 2017年 第11卷 第4期   页码 594-602 doi: 10.1007/s11705-017-1668-5

摘要： A mild deposition method was used to fabricate Mn-based catalysts on a UiO-66 carrier for the selective catalytic reduction of NO by NH (NH -SCR). The catalyst with 8.5 wt-% MnO loading had the highest catalytic activity for NH -SCR with a wide temperature window (100–290 °C) for 90% NO conversion. Characterization of the prepared MnO /UiO-66 catalysts showed that the catalysts had the crystal structure and porosity of the UiO-66 carrier and that the manganese particles were well-distributed on the surface of the catalyst. X-ray photoelectron spectroscopy analysis showed that there are strong interactions between the MnO and the Zr oxide secondary building units of the UiO-66 which has a positive effect on the catalytic activity. The 8.5 wt-% MnO catalyst maintained excellent activity during a 24-h stability test and exhibited good resistance to SO poisoning.

关键词： metal-organic framework     selective catalytic reduction     manganese oxides     deNOx     SO2 resistance    

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Selective catalytic reduction of NO

Pavlo I. Kyriienko

《化学科学与工程前沿（英文）》 2020年 第14卷 第4期   页码 471-491 doi: 10.1007/s11705-019-1847-7

摘要： Research results regarding selective catalytic reduction (SCR) of NO with ethanol and other C oxygenates as reductants over silver-alumina catalysts are summarized. The aspects of the process mechanism, nature of active sites, role of alumina and silver (especially in the formation of bifunctional active sites), effects of reductants and reaction conditions are discussed. It has been determined that key stages of the process include formation of reactive enolic species, their interaction with NO and formation of nitroorganic compounds which transform to NCO species and further to N . The results obtained over various silver-alumina catalysts demonstrate the perspectives of their application for reducing the level of nitrogen oxides in engine emissions, including in the presence of water vapor and sulfur oxides. Ways to improve the catalysts for the SCR of NO with C oxygenates are outlined.

关键词： SCR     nitrogen oxides     silver-alumina catalyst     silver species     ethanol     oxygenates    

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Selective catalytic reduction of NOx from exhaust of lean-burn engine over Ag-Al2O3/cordierite catalyst

LI Junhua, KANG Shoufang, FU Lixin, HAO Jiming

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 143-146 doi: 10.1007/s11783-007-0025-1

摘要： A highly effective Ag-AlO catalyst was prepared using the sol-gel method, and characterized by surface area using nitrogen adsorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The catalyst performance was tested on a real lean-burn gasoline engine. Only unburned hydrocarbons and carbon monoxide in the exhaust were directly used as reductant (without any external reductant), the maximum NO conversion could only reach 40% at 450?C. When an external reductant, ethanol was added, the average NO conversion was greater than 60%. At exhaust gas temperature range of 350 500?C, the maximum NO conversion reached about 90%. CO and HC could be efficiently oxidized with Pt-AO oxidation catalyst placed at the end of SCR converter. However, NO conversion drastically decreased because of the oxidation of some intermediates to NO again. The possible reaction mechanism was proposed as two typical processes, nitration, and reduction in HC-SCR over Ag-AlO.

关键词： lean-burn gasoline     external reductant     nitrogen adsorption     conversion     catalyst performance    

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Nitrous oxide formation and emission in selective non-catalytic reduction process

YANG Weijuan, ZHOU Junhu, ZHOU Zhijun, CEN Kefa

《能源前沿（英文）》 2007年 第1卷 第2期   页码 228-232 doi: 10.1007/s11708-007-0031-9

摘要： Pulverized coal-fired boilers are not nitrous oxide sources because of high temperature combustion. But selective non-catalytic reduction may produce NO by NO reduction reactions. Chemical kinetics calculation and experimental research were used to find out the mechanism between NO and N-agent species, N-agent/NO nitrogen stoichiometric ratio (NSR), reaction temperature, reaction time, etc. The results show that NO emission decreases with increasing reaction temperature and NSR decreases when reaction time is enough. NO concentration first increases then decreases as SNCR reactions keep on occuring. Ammonia SNCR tests indicated that NO emission was 0 7 μmol/mol. About 8.7% of NO was transformed to NO, and NO emission was 27.8 μmol/mol at urea-SNCR test. Urea-SNCR is likely to bring NO emission problem.
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Recent advances and challenges of nitrogen/nitrate electro catalytic reduction to ammonia synthesis

《能源前沿（英文）》 doi: 10.1007/s11708-023-0908-2

摘要： The Haber-Bosch process is the most widely used synthetic ammonia technology at present. Since its invention, it has provided an important guarantee for global food security. However, the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution. Under the serious pressure of energy and environment, a green, clean, and sustainable ammonia synthesis route is urgently needed. Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia, which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar, wind, or water energy, without greenhouse gas and toxic gas emissions. Herein, the basic mechanism of the nitrogen reduction reaction (NRR) to ammonia and nitrate reduction reaction (NO3− RR) to ammonia were discussed. The representative approaches and major technologies, such as lithium mediated electrolysis and solid oxide electrolysis cell (SOEC) electrolysis for NRR, high activity catalyst and advanced electrochemical device fabrication for NO3 − RR and electrochemical ammonia synthesis were summarized. Based on the above discussion and analysis, the main challenges and development directions for electrochemical ammonia synthesis were further proposed.

关键词： electrochemical ammonia synthesis     nitrogen     nitrate     nitrogen reduction reaction (NRR) to ammonia     nitrate reduction reaction (NO–3 RR)    

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标题 作者 时间 类型 操作

Effect of different acid anions on highly efficient Ce-based catalysts for selective catalytic reductionof NO with NH3

期刊论文

Low-temperature selective catalytic reduction of NO with NH based on MnO-CeO/ACFN

SHEN Boxiong, LIU Ting, SHI Zhanliang, SHI Jianwei, YANG Tingting, ZHAO Ning

期刊论文

On the monolayer dispersion behavior of Co3O4 on HZSM-5 support: designing applicablecatalysts for selective catalytic reduction of nitrogen oxides by ammonia

期刊论文

Promotion of transition metal oxides on the NH

Weiman Li, Haidi Liu, Yunfa Chen

期刊论文

NiBO (B = Mn or Co) catalysts for NH-SCR of NO at low-temperature in microwave field

期刊论文

Characterization and performance of V

Caiting LI, Qun LI, Pei LU, Huafei CUI, Guangming ZENG

期刊论文

Multi-stage ammonia production for sorption selective catalytic reduction of NO

Chen ZHANG, Guoliang AN, Liwei WANG, Shaofei WU

期刊论文

Effects of support acidity on the reaction mechanisms of selective catalytic reduction of NO by CH

Shicheng XU, Junhua LI, Dong YANG, Jiming HAO

期刊论文

Design and operational considerations for selective catalytic reduction technologies at coal-fired boilers

Jeremy J. SCHREIFELS, Shuxiao WANG, Jiming HAO

期刊论文

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selectivecatalytic reduction of NO

期刊论文

Metal-organic framework loaded manganese oxides as efficient catalysts for low-temperature selectivecatalytic reduction of NO with NH

Minhua Zhang, Baojuan Huang, Haoxi Jiang, Yifei Chen

期刊论文

Selective catalytic reduction of NO

Pavlo I. Kyriienko

期刊论文

Selective catalytic reduction of NOx from exhaust of lean-burn engine over Ag-Al2O3/cordierite catalyst

LI Junhua, KANG Shoufang, FU Lixin, HAO Jiming

期刊论文

Nitrous oxide formation and emission in selective non-catalytic reduction process

YANG Weijuan, ZHOU Junhu, ZHOU Zhijun, CEN Kefa

期刊论文

Recent advances and challenges of nitrogen/nitrate electro catalytic reduction to ammonia synthesis

期刊论文