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Promotional effect of phosphorylation on CeSn_(0.8)W_(0.6)O_x/TiAl_(0.2)Si_(0.1)O_y for NH_3-SCR of NO from marine diesel exhaust 被引量:2
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作者 韩冰 沈岳松 +2 位作者 祝社民 刘优林 沈树宝 《Journal of Rare Earths》 SCIE EI CAS CSCD 2016年第10期1010-1016,共7页
A series of phosphorylation and blank CeSn_(0.8)W_(0.6)O_x/TiAl_(0.2)Si_(0.1)O_y catalysts prepared by extrusion molding were tested for NH_3-SCR of NO, and were characterized by techniques of X-ray diffractio... A series of phosphorylation and blank CeSn_(0.8)W_(0.6)O_x/TiAl_(0.2)Si_(0.1)O_y catalysts prepared by extrusion molding were tested for NH_3-SCR of NO, and were characterized by techniques of X-ray diffraction(XRD), Brumauer-Emmett-Teller(N_2-BET), environmental scanning electron microscope(ESEM), temperature programmed reduction(H_2-TPR) and temperature programmed desorption(NH_3-TPD). Effects of phosphorylation on catalytic activity and sulfur-resisting performance of the CeSn_(0.8)W_(0.6)O_x/TiAl_(0.2)Si_(0.1)O_y for NH_3-SCR of NO were mainly studied. Results showed that the phosphorylation improved the catalytic activity and sulfur-resisting performance in an active temperature window of 300–440 °C, and the phosphorylation catalyst with 0.4 wt.% H_3PO_4 exhibited the best catalytic performance and the strongest sulfur-resisting performance. Analysis showed that the phosphorylation increased specific surface area, enhanced the surface acidity and improved redox properties. 展开更多
关键词 CeSn_(0.8)W_(0.6)O_x/TiAl_(0.2)Si_(0.1)O_y phosphorylation diesel engine exhaust sulfur-resisting nh_3-scr NO conversion rare earths
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Mechanism of enhancing NH_(3)-SCR performance of Mn-Ce/AC catalyst by the structure regulation of activated carbon with calcite in coal
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作者 NIU Jian LI Yuhang +4 位作者 BAI Baofeng WEN Chaolu LI Linbo ZHANG Huirong GUO Shaoqing 《燃料化学学报(中英文)》 北大核心 2026年第1期69-79,共11页
To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ... To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced. 展开更多
关键词 CALCITE activated carbon structure Mn-Ce/AC catalyst nh_(3)-scr performance
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Nb改性对Cu/Zr-PILC催化剂NH_(3)-SCR性能的影响
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作者 刘文逸 王新鹏 +4 位作者 曲超 孟繁伟 杨帆 张鑫 叶青 《环境化学》 北大核心 2025年第4期1437-1448,共12页
本文通过浸渍法制备了一系列yNb-3Cu/Zr-PILC(y=1%、1.5%、3%)催化剂,并对其NH_(3)-SCR活性进行了评估.研究发现,Nb的改性有效提高了3Cu/Zr-PILC的脱硝效率,拓宽了活性窗口.其中活性最佳的1.5Nb-3Cu/Zr-PILC样品在300—400℃宽温度范围... 本文通过浸渍法制备了一系列yNb-3Cu/Zr-PILC(y=1%、1.5%、3%)催化剂,并对其NH_(3)-SCR活性进行了评估.研究发现,Nb的改性有效提高了3Cu/Zr-PILC的脱硝效率,拓宽了活性窗口.其中活性最佳的1.5Nb-3Cu/Zr-PILC样品在300—400℃宽温度范围内的NO转化率超过90%,在350℃时达到峰值95.04%,并表现出了优异的SO_(2)耐受性.利用XRD、BET、H2-TPR、NH_(3)-TPD、XPS和In-situ DRIFTS技术对各催化剂的理化性质进行了研究.根据TPR和TPD结果可知,1.5Nb-3Cu/Zr-PILC催化剂具有最突出的氧化还原特性和表面酸性强度,有利于催化反应进行.XPS结果表明,1.5Nb-3Cu/Zr-PILC催化剂中Cu和Nb物种之间存在最强的相互作用,提高了Cu^(2+)/Cu+的原子比,并产生了更多的化学吸附氧.此外,In-situ DRIFTS结果表明,在3Cu/Zr-PILC上添加Nb物种有利于在催化剂表面形成更多的NH_(3)和NO_(x)中间体,这同样有助于NH_(3)-SCR过程的进行. 展开更多
关键词 NB 改性 CU 负载 Zr-PILC nh_(3)-scr.
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Cr掺杂La-Mn钙钛矿催化剂强化NH_(3)-SCR脱硝性能
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作者 焦玉琳 王新华 罗晓军 《环境化学》 北大核心 2025年第1期334-342,共9页
采用共沉淀法制备了LaMn_(1-y)Cr_(y)O_(3)(y=0、0.05、0.1、0.2、0.4)钙钛矿催化剂,并将其用于模拟烟气中NO的脱除,通过XRD、SEM、BET、XPS和DRIFT等表征研究了催化剂的物化性能及反应机理.在300℃时,LaMnO3的NO转化率为75.8%,在Cr掺... 采用共沉淀法制备了LaMn_(1-y)Cr_(y)O_(3)(y=0、0.05、0.1、0.2、0.4)钙钛矿催化剂,并将其用于模拟烟气中NO的脱除,通过XRD、SEM、BET、XPS和DRIFT等表征研究了催化剂的物化性能及反应机理.在300℃时,LaMnO3的NO转化率为75.8%,在Cr掺杂比为0.1时NO的转化率达到最高91.3%.从表征结果来看,Cr的掺杂使催化剂发生了晶格畸变同时改变了催化剂的形貌,产生了较多的活性位点和较大的表面积.金属间的协同作用(2Cr^(6+)+3Mn^(2+)↔2Mn^(3+)+3Cr^(2+)+2Cr^(3+))和高浓度的化学吸附氧和晶格氧都加强了催化剂表面的氧化还原反应,从而使LaMn_(0.9)Cr_(0.1)O_(3)催化剂具有较好的脱硝活性.经过改性后的催化剂对硫酸盐的抵抗能力有了大幅提高,归因于增大的比表面积和孔结构增加了活性位点数量.因此,适当的Cr取代能显著提高La-Mn钙钛矿催化剂的脱硝活性. 展开更多
关键词 钙钛矿 nh_(3)-scr 掺杂 机理 NO_(x)
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燃煤烟气NH_(3)-SCR催化剂研究进展 被引量:1
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作者 吴荫南 《现代化工》 北大核心 2025年第S1期29-35,共7页
从NH_(3)-SCR催化剂设计和性能调控角度出发,讨论了不同种类的NH_(3)-SCR催化剂的研究成果,阐述了NH_(3)-SCR催化剂的中毒失活机制,介绍了高性能NH_(3)-SCR催化剂的改性和回收方法,并对未来NH_(3)-SCR催化剂的研究和应用提出展望。
关键词 燃煤烟气 nh_(3)-scr 催化剂 稳定性 改性 回收
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造孔剂对酸活化稀土尾矿成型NH_(3)-SCR脱硝催化剂的影响
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作者 侯丽敏 王新展 +5 位作者 叶雨乔 李佳明 孙现康 卢林博 陈瀚 武文斐 《稀有金属与硬质合金》 北大核心 2025年第5期51-58,共8页
为了提高酸活化成型NH_(3)-SCR脱硝催化剂的脱硝性能,以稀土尾矿为原料,向硫酸活化和微波处理后的粉末催化剂中添加不同造孔剂(淀粉、聚乙二醇、碳酸铵、活性炭),经挤压成型后制备NH_(3)-SCR脱硝催化剂。采用NH_(3)-SCR测试和X射线衍射... 为了提高酸活化成型NH_(3)-SCR脱硝催化剂的脱硝性能,以稀土尾矿为原料,向硫酸活化和微波处理后的粉末催化剂中添加不同造孔剂(淀粉、聚乙二醇、碳酸铵、活性炭),经挤压成型后制备NH_(3)-SCR脱硝催化剂。采用NH_(3)-SCR测试和X射线衍射、比表面积测试、氢气程序升温还原等方法,分别探讨了不同造孔剂及其用量对催化剂的脱硝活性、抗压强度、比表面积、孔结构、物相组成、氧化还原能力的影响,从而确定造孔剂的最优种类及最佳用量。结果表明:加入质量分数为5.0%的聚乙二醇后,成型催化剂具有相对最优的脱硝性能,其比表面积为3.70 m^(2)/g,总孔体积为0.0308 cm^(3)/g,350℃下的脱硝效率为74.0%,并具有较高的N_(2)选择性、抗压强度以及氧化还原能力,相较于未添加造孔剂成型的催化剂而言,脱硝性能明显提升。 展开更多
关键词 造孔剂 酸活化 稀土尾矿 nh_(3)-scr 催化剂 脱硝 聚乙二醇
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稀土铈基NH_(3)-SCR催化剂抗金属离子中毒研究进展
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作者 王瑞华 邹伟欣 +1 位作者 聂玮 董林 《中国稀土学报》 北大核心 2025年第3期490-501,共12页
在NH_(3)-SCR研究领域,稀土铈基材料因其良好的储释氧能力而备受关注。实际烟气所含的各种金属离子杂质会造成催化剂的失活,近年来,大量研究者针对稀土铈基催化剂金属离子中毒问题进行了深入探究。本文较为系统地综述了稀土铈基NH_(3)-... 在NH_(3)-SCR研究领域,稀土铈基材料因其良好的储释氧能力而备受关注。实际烟气所含的各种金属离子杂质会造成催化剂的失活,近年来,大量研究者针对稀土铈基催化剂金属离子中毒问题进行了深入探究。本文较为系统地综述了稀土铈基NH_(3)-SCR催化剂的金属离子中毒机制和抗中毒提升策略,并对未来抗金属离子中毒的铈基催化剂的发展进行了展望,期望为相关研究提供一定参考借鉴。 展开更多
关键词 稀土铈基催化剂 nh_(3)-scr 抗金属离子中毒
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Stability enhancement of MnO_(x)-CeO_(2)via hydrophobic modification for NO reduction by NH_(3)
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作者 Boyu Wu Shengen Zhang +2 位作者 Shengyang Zhang Bo Liu Bolin Zhang 《International Journal of Minerals,Metallurgy and Materials》 2026年第1期357-368,共12页
MnO_(x)-CeO_(2)catalysts for the low-temperature selective catalytic reduction(SCR)of NO remain vulnerable to water and sulfur poisoning,limting their practical applications.Herein,we report a hydrophobic-modified MnO... MnO_(x)-CeO_(2)catalysts for the low-temperature selective catalytic reduction(SCR)of NO remain vulnerable to water and sulfur poisoning,limting their practical applications.Herein,we report a hydrophobic-modified MnO_(x)-CeO_(2)catalyst that achieves enhanced NO conversion rate and stability under harsh conditions.The catalyst was synthesized by decorating MnOx crystals with amorphous CeO_(2),followed by loading hydrophobic silica on the external surfaces.The hydrophobic silica allowed the adsorption of NH_(3)and NO and diffusion of H,suppressed the adsorption of H_(2)O,and prevented SO_(2)interaction with the Mn active sites,achieving selective molecular discrimination at the catalyst surface.At 120℃,under H_(2)O and SO_(2)exposure,the optimal hydrophobic catalyst maintains 82%NO conversion rate compared with 69%for the unmodified catalyst.The average adsorption energies of NH_(3),H_(2)O,and SO_(2)decreased by 0.05,0.43,and 0.52 eV,respectively.The NO reduction pathway follows the Eley-Rideal mechanism,NH_(3)^(*)+*→NH_(2)^(*)+H^(*)followed by NH_(2)^(*)+NO^(*)→N_(2)^(*)+H_(2)O^(*),with NH_(3)dehydrogenation being the rate determining step.Hydrophobic modification increased the activation energy for H atom transfer,leading to a minor decrease in the NO conversion rate at 120℃.This work demonstrates a viable strategy for developing robust NH_(3)-S CR catalysts capable of efficient operation in water-and sulfur-rich environments. 展开更多
关键词 Mn-Ce catalyst nh_(3)-scr hydrophobic modification enhanced stability
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Promotion effect of Ce and Ta co-doping on the NH_(3)-SCR performance over V_(2)O_(5)/TiO_(2)catalyst 被引量:1
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作者 Long Liu Xin Shen +4 位作者 Zhihua Lian Chunxi Lin Ying Zhu Wenpo Shan Hong He 《Journal of Environmental Sciences》 2025年第4期332-339,共8页
NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.A... NH_(3)-SCR(SCR:Selective catalytic reduction)is an effective technology for the de-NO_(x)process from both mobile and stationary pollution sources,and the most commonly used catalysts are the vanadia-based catalysts.An innovative V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst for NO_(x)removal was prepared in this study.The influences of Ce and Ta in the V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst on the SCR performance and physicochemical properties were investigated.The V_(2)O_(5)-CeO_(2)/TaTiO_(x)catalyst not only exhibited excellent SCR activity in a wide temperature window,but also presented strong resistance to H_(2)Oand SO_(2)at 275◦C.A series of characterizationmethods was used to study the catalysts,including H2-temperature programmed reduction,X-ray photoelectron spectroscopy,NH_(3)-temperature programmed desorption,etc.It was discovered that a synergistic effect existed between Ce and Ta species.The introduction of Ce and Ta enlarged the specific surface area,increased the amount of acid sites and the ratio of Ce^(3+),(V^(3+)+V^(4+))and Oα,and strengthened the redox capability which were related to synergistic effect between Ce and Ta species,significantly improving the NH_(3)-SCR activity. 展开更多
关键词 nh_(3)-scr Vanadia-based catalysts Synergistic effect CO-DOPING Low temperature
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燃煤锅炉烟气中NH_(3)-SCR钒基催化剂宽温脱硝的研究进展
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作者 李家威 张博雅 +1 位作者 沈凯 张亚平 《燃料化学学报(中英文)》 北大核心 2025年第12期1726-1738,共13页
氮氧化物(NO_(x))作为主要大气污染物之一,对人类健康和大气环境造成严重危害。NH_(3)-SCR技术作为固定源氮氧化物减排的重要手段,在燃煤发电行业得到广泛应用,而V基催化剂因其优异的脱硝活性受到广泛关注。但由于能源产业的深刻变革,传... 氮氧化物(NO_(x))作为主要大气污染物之一,对人类健康和大气环境造成严重危害。NH_(3)-SCR技术作为固定源氮氧化物减排的重要手段,在燃煤发电行业得到广泛应用,而V基催化剂因其优异的脱硝活性受到广泛关注。但由于能源产业的深刻变革,传统V基催化剂已经无法满足行业要求,因此,对V基催化剂进行改性,使其能够在较宽的温度范围内工作,提高其抗中毒能力已成为燃煤发电行业的迫切需求。本工作概述了近几年燃煤发电行业V基催化剂宽温脱硝抗中毒相关研究。在低温性能改进方面,可通过对活性组分、载体进行改性以及优化催化剂结构,有效拓宽温度窗口;在失活因素研究上,剖析硫酸氢氨(ABS)、H_(2)O、碱/碱土金属、磷以及卤素的中毒机理,并介绍相应提升抗中毒性能的方法。提出V基催化剂在发电行业能源转型中值得重点关注的研究方向。 展开更多
关键词 nh_(3)-scr V基 宽温脱硝 抗中毒性能
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Hydrothermal aging alleviates hydrocarbon poisoning effects on high-silica Cu-SSZ-16 catalysts for NH_(3)-SCR
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作者 Huan Zhou Jianqi Liu +3 位作者 Yan Zhang Shichao Han Jinpeng Du Wenpo Shan 《Journal of Environmental Sciences》 2025年第12期13-23,共11页
Hydrocarbons(HCs)exert toxic effects on the activity of Cu-based zeolite catalysts for NH_(3)-SCR on diesel vehicles.This study inve stigated the hydrocarbon resistance of both fresh and hydrothermally aged high-silic... Hydrocarbons(HCs)exert toxic effects on the activity of Cu-based zeolite catalysts for NH_(3)-SCR on diesel vehicles.This study inve stigated the hydrocarbon resistance of both fresh and hydrothermally aged high-silica Cu-SSZ-16 catalysts.It was found that low-temperature activity of Cu-SSZ-16 catalyst decreased after C_(3)H_(6) poisoning,which was mainly due to the blockage of pore channels and the coverage of Cu active sites as well as acid sites by the formation of carbon deposits.Additionally,[Cu(OH)]^(+)-Z was proposed to be more easily affected by C_(3)H_(6) poisoning than Cu^(2+)-2Z.Hydrothermally aged Cu-SSZ-16 presented better C_(3)H_(6) resistance than the fresh catalyst since less carbon deposits were accumulated and[Cu(OH)]^(+)-Z species were partially transformed to more-stable Cu^(2+)-2Z in the aged sample.This was probably because of the reduction of acid sites and the formation of CuO_(x),which enhanced the oxidation of C_(3)H_(6),thereby inhibiting the formation of carbon deposits.In addition,the coverage of the active Cu species also influenced the adsorption and oxidation of NO,causing a decrease in low-temperature activity.Thus,the low-temperature activity could be fully recovered by hydrothermal treatment at 500℃due to the removal of carbon deposits and recovery of Cu active sites as well as acid sites.In summary,high-silica CuSSZ-16,with high resistance to HCs and excellent hydrothermal stability,is a competitive candidate as a catalyst for the NH_(3)-SCR reaction in practical application. 展开更多
关键词 Hydrocarbon poisoning Hydrothermal aging Cu-SSZ-16 nh_(3)-scr Diesel exhaust
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NH_(3)-SCR低温烟气脱硝催化剂中毒机理研究
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作者 沈亭 《皮革制作与环保科技》 2025年第14期147-149,共3页
氮氧化物是工业排放的大气环境污染物之一。目前,工业上常用的烟气脱硝方法是以氨为还原剂的选择性催化还原法(NH_(3)-SCR),该方法被认为是去除氮氧化物最有效的方法,去除率可达90%以上。在该技术的应用中,催化剂具有重要作用,但是烟气... 氮氧化物是工业排放的大气环境污染物之一。目前,工业上常用的烟气脱硝方法是以氨为还原剂的选择性催化还原法(NH_(3)-SCR),该方法被认为是去除氮氧化物最有效的方法,去除率可达90%以上。在该技术的应用中,催化剂具有重要作用,但是烟气中存在的二氧化硫、水蒸气、碱金属、重金属和卤素等会导致催化剂中毒失活,从而降低氮氧化物的去除效果。因此,采用对催化剂进行金属氧化物修饰或合成载体的方法,提高催化剂的抗中毒能力是当下研究的热点。本文总结了提高催化剂低温抗中毒性能的机理,并对催化剂的进一步发展进行了展望。 展开更多
关键词 nh_(3)-scr 氮氧化物 水中毒 硫中毒
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Praseodymium effects on greatly improving low-temperature hydrothermal stability of Cu/SAPO-34 NH_(3)-SCR catalysts
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作者 Xiaojie Yu Xinyu Li +4 位作者 Chen Wang Jianqiang Wang Meiqing Shen M.D.Tarikul Islam Gurong Shen 《Journal of Rare Earths》 2025年第4期707-718,I0003,共13页
Based on the previous findings that the presence of hydroxyl groups on the outer surface is crucial for maintaining skeletal stability,we propose a strategy modified Cu/SAPO-34 using Pr ions in this study.Therefore,we... Based on the previous findings that the presence of hydroxyl groups on the outer surface is crucial for maintaining skeletal stability,we propose a strategy modified Cu/SAPO-34 using Pr ions in this study.Therefore,we conducted several measurements to investigate the effect of Pr ions on the lowtemperature hydrothermal stability of Cu/SAPO-34.We find that Pr exists only on the surface of Cu/SAPO-34 as ions and oxides,with Pr^(3+)ions playing a protective role in occupying surface acidic sites.The addition of small amounts of Pr leads to the re-dispersion of Cu,resulting in improved lowtemperature selective catalytic reduction(SCR)activity in the as-synthesized samples.Furthermore,it enhances the resistance to decomposition of the Si-(OH)-Al framework during low-temperature hydrothermal aging,thereby preserving the framework structure and allowing detached active Cu species to return to exchangeable positions,ultimately restoring SCR activity.However,as the Pr content increases,the enhanced acidity causes some structural damage,gradually weakening the protective effect.Our work demonstrates that Pr modification is a simple and effective solution to the issue of poor lowtemperature hydrothermal stability in Cu/SAPO-34,providing a promising way for the application of light rare earth elements. 展开更多
关键词 nh_(3)-scr Pr modification Cu/SAPO-34 Low-temperature hydrothermal stability Rare earths
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Remarkable Enhancement of the Activity and Hydrothermal Stability of a CeO_(2)-Based NH_(3)-SCR Catalyst by Sn Modification
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作者 Ying Zhu Jingjing Liu +5 位作者 Guangzhi He Shaohua Xie Wenpo Shan Zhihua Lian Fudong Liu Hong He 《Engineering》 2025年第5期141-150,共10页
Catalytic activity and hydrothermal stability are both crucial for the application of the selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR)catalyst in diesel vehicles.In this study,a tin(Sn)-modified Ce-N... Catalytic activity and hydrothermal stability are both crucial for the application of the selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR)catalyst in diesel vehicles.In this study,a tin(Sn)-modified Ce-Nb mixed-oxide catalyst was synthesized as an NH_(3)-SCR catalyst for NO_(x)emission control.After the intro-duction of Sn,both the NH_(3)-SCR activity and the hydrothermal stability of the catalyst were remarkably promoted.Even after hydrothermal aging at 1000℃,the developed Ce_(1)Sn_(2)Nb_(1)O_(x)catalyst achieved more than 90%NO_(x)conversion at 325-500℃.Various methods,including N2-physisorption,X-ray diffraction,in-situ high-temperature X-ray diffraction,high-resolution transmission electron microscopy,X-ray pho-toelectron spectroscopy,X-ray absorption fine-structure spectroscopy,temperature-programmed reduc-tion of hydrogen,temperature-programmed desorption of ammonia,and density functional theory calculations were used to investigate the promotional effects induced by the Sn species.The characteri-zation results showed that the addition of Sn not only promoted the formation of the Ce-Nb active phase but also improved its thermal stability,contributing to the excellent NH_(3)-SCR performance and hydrothermal stability.This study provides an excellent sintering-resistance catalyst for the application of diesel engine NO_(x)emission control. 展开更多
关键词 SnO_(2) CeO_(2)-based catalyst nh_(3)-scr Hydrothermal stability NO_(x)emission control
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Towards rational design of Cu-SSZ-13 catalysts with less N_(2)O formation in NH_(3)-SCR reaction:The effect of BrФsted acid sites
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作者 Jianqi Liu Jinpeng Du +9 位作者 Jingyi Wang Shichao Han Yulong Shan Yan Zhang Xuanhao Wu Shan Gao Yunbo Yu Zhongbiao Wu Wenpo Shan Hong He 《Journal of Environmental Sciences》 2025年第11期546-557,共12页
Ammonia Selective Catalytic Reduction(NHs-SCR)technology has been employed to eliminate NO_(x) from diesel engine exhaust,with Cu-SSZ-13 serving as the commercial catalyst.The greenhouse gas N_(2)O is produced as a by... Ammonia Selective Catalytic Reduction(NHs-SCR)technology has been employed to eliminate NO_(x) from diesel engine exhaust,with Cu-SSZ-13 serving as the commercial catalyst.The greenhouse gas N_(2)O is produced as a byproduct when using Cu-SSZ-13 as the NH_(3)-SCR catalyst.To achieve synergistic control of pollutants and greenhouse gases in diesel engine exhaust,rational design of Cu-SSZ-13 catalysts is required.In this study,the effect of Brønsted acid sites in Cu-SSZ-13 catalysts on the formation of N_(2)O was investigated.Mild thermal treatmentwas innovatively employed to prepare Cu-SSZ-13 catalysts with different amounts of Brønsted acid sites.EPR,H_(2)-TPR,NH_(3)-TPD,NMR were utilized to determine that the Brønsted acid sites were modified while the Cu species remained unchanged.Thereby an accurate assessment of the influence of Brønsted acid sites on N_(2)O formation could be achieved.Our results showed that Cu-SSZ-13 with more Brønsted acid sites produced less N_(2)O during the NH_(3)-SCR reaction.In the low-temperature region,the presence of framework acid sites facilitates the decomposition of the NH_(4)NO_(3)assisted by NO to form N_(2)and H_(2)O,reducing the formation of N_(2)O.In the high-temperature region,the Brønsted acid sites promote the decomposition of NH_(2)NO into N_(2)and H_(2)O.Meanwhile,the N_(2)O-SCR reaction can also be promoted by Brønsted acid sites,thereby decreasing N_(2)O emissions.This study suggests that in the future design and synthesis of Cu-SSZ-13 zeolites,attention should be paid to creating more Brønsted acid sites in Cu-SSZ-13 to reduce N_(2)O emissions. 展开更多
关键词 nh_(3)-scr NO_(x)abatement N_(2)O emission control Cu-SSZ-13 zeolite Brønsted acid sites
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K^(+)诱导Mn-Ce固溶体增强酸性和活性氧协同促进NH_(3)-SCR 被引量:1
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作者 陈曦 王小燕 +2 位作者 李巧艳 王梦雪 梁美生 《中国环境科学》 EI CAS CSCD 北大核心 2024年第11期6036-6046,共11页
本文采用水热驱动将K离子引入制备的Mn-Ce固溶体晶格中(MnCeOx),优化其结构特征并用于NH_(3)-SCR反应.H_(2)-TPR和O_(2)-TPD结果表明,K的加入极大的弱化了Mn-O键,进而导致催化剂的还原性和氧脱附能力的提升;XPS,NH_(3)-TPD和原位红外(in... 本文采用水热驱动将K离子引入制备的Mn-Ce固溶体晶格中(MnCeOx),优化其结构特征并用于NH_(3)-SCR反应.H_(2)-TPR和O_(2)-TPD结果表明,K的加入极大的弱化了Mn-O键,进而导致催化剂的还原性和氧脱附能力的提升;XPS,NH_(3)-TPD和原位红外(insitu DRIFTs)结果表明,K的引入可以增强Mn/Ce元素间的电子转移,同时提高催化剂中氧缺陷的数量以及BrФnsted酸性位对NH_(3)的吸附能力.因此,在增强的酸性位点与缺陷吸附活性氧的协同作用下,促进了催化剂MnCeK_(y)O_(x)在NH_(3)-SCR反应中的活性和反应速率.当K、Ce、Mn元素的比例为1:5:5时,在较低温度(120℃)下,MnCeK_(1)O_(x)催化剂的NO转化率为94.6%,在40~260℃的较宽温度范围内可以实现NO的高效转化.采用in situ FTIR对NH_(3)和NO原位吸附和反应过程进行分析,结果表明NH_(3)的吸附比NO更敏感.对于MnCeO_(x),NH_(3)首先吸附在Lewis酸位点上,然后结合在BrФnsted酸位点上,导致单配位基和双配位基硝酸盐同时聚集;对于Mn CeK_(1O)_(x),NH_(3)同时吸附在Lewis和BrФnsted酸性位上,其中间产物仅为单配位基硝酸盐.结果表明K离子的添加可以有效的提升Mn-Ce固溶体在NH_(3)-SCR反应中的效率. 展开更多
关键词 nh_3-scr 钾离子 Mn-Ce固溶体 酸性 活性氧
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过渡金属改性锰金属有机骨架催化剂低温NH_(3)-SCR脱硝活性研究 被引量:2
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作者 李海霞 杨昌泽 +2 位作者 张安超 孙志君 张新民 《煤炭学报》 EI CAS CSCD 北大核心 2022年第S01期356-364,共9页
采用过渡金属硝酸盐溶液浸渍Mn-MOF(金属有机骨架)前驱体材料,经过煅烧后获得了3种掺杂型锰基催化剂:MnFeO_(x),MnNiO_(x)和MnCeO_(x)。对MnMeO_(x)催化剂进行低温氨气选择性催化还原(NH_(3)-SCR)活性及抗硫性能测试。结果表明,在空速(G... 采用过渡金属硝酸盐溶液浸渍Mn-MOF(金属有机骨架)前驱体材料,经过煅烧后获得了3种掺杂型锰基催化剂:MnFeO_(x),MnNiO_(x)和MnCeO_(x)。对MnMeO_(x)催化剂进行低温氨气选择性催化还原(NH_(3)-SCR)活性及抗硫性能测试。结果表明,在空速(GHSV)为30000 h^(-1)下,MnFeO_(x)和MnNiO_(x)催化剂表现出最佳的低温NH_(3)-SCR脱硝性能和抗硫性能,脱硝效率大于90%的工作窗口范围分别为100~250℃和125~275℃。铈元素的掺杂未能显著提高催化剂的脱硝性能。不同空速测试结果表明,空速对催化剂性能有显著影响,空速越大催化剂脱硝效率越低,但对N_(2)O的生成量影响较小。通过X-射线粉末衍射(XRD)、扫描电子显微镜(SEM)、N_(2)吸附-脱附、X射线光电子能谱(XPS)、氢气程序升温还原性能测试(H_(2)-TPR)、氨气程序升温脱附测试(NH_(3)-TPD)等对掺杂催化剂的理化性质进行研究。结果表明,铁或镍的掺杂增大了催化剂的比表面积,改变了Mn-MOF烧结过程中MnO_(x)晶体的成型过程,增加了催化剂表面Mn^(4+)和表面氧(Oα)含量,改善了催化剂的氧化还原性能,增加了催化剂的活性位点。相比之下,铈元素的掺杂降低了催化剂的比表面积和表面氧含量,抑制了催化剂的氧化还原性能和表面活性位点的形成,导致其脱硝活性较差。研究表明,适当的硝酸盐浸渍Mn-MOF能够制备高效的低温NH_(3)-SCR脱硝催化剂。 展开更多
关键词 Mn-MOF MnO_(x)基 nh_(3)-scr 浸渍法 低温
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氟碳铈精矿矿物学分析及负载锰的NH_(3)-SCR脱硝性能的研究 被引量:3
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作者 李娜 陈泽东 +4 位作者 李华 武文斐 侯丽敏 王晶晶 张凯 《中国稀土学报》 CAS CSCD 北大核心 2021年第6期890-902,I0002,共14页
利用X射线荧光光谱分析仪(XRF)、扫描电镜(SEM)、矿物特征自动定量分析系统(AMICS)对氟碳铈精矿的元素组成,矿物间连生关系以及粒度分布、表面形貌等进行了分析。结果表明:氟碳铈精矿中的矿物组成复杂,矿物粒度呈细小颗粒状,主要以氟碳... 利用X射线荧光光谱分析仪(XRF)、扫描电镜(SEM)、矿物特征自动定量分析系统(AMICS)对氟碳铈精矿的元素组成,矿物间连生关系以及粒度分布、表面形貌等进行了分析。结果表明:氟碳铈精矿中的矿物组成复杂,矿物粒度呈细小颗粒状,主要以氟碳铈矿和独居石矿相为主,稀土元素(Ce,La,Nd)也主要赋于二者之中。为了研究氟碳铈精矿的NH_(3)-SCR的脱硝性能,及其作为载体的优势,采用过量浸渍法制备了一系列Mn/氟碳铈精矿催化剂,选用NH_(3)-SCR催化剂的常用载体Al_(2)O_(3)作为对比。通过XRD,BET,NH_(3)(NO)-TPD,H_(2)-TPR,活性测试等实验分析手段对所制备的催化剂进行物理化学性质分析。结果表明:Mn/氟碳铈精矿催化剂表现出最佳的脱硝性能,在150℃条件下NO转化率最高可达85%,这主要归因于Mn可以很好的与氟碳铈精矿相互作用,使得MnO_(3)物种的分散性更好。MnO_(3)物种多以无定形态分布在氟碳铈精矿表面,通过计算催化剂的晶胞常数可得氟碳铈精矿与Mn的结合效果最佳。Mn(NO_(3))_(3)溶液作为前驱体,为催化剂提供了更多的表面酸性位点。Mn^(n+),Ce^(n+)等离子价态的变化释放了更多氧空位有利于氧迁徙,相比于常规载体Al_(2)O_(3),氟碳铈精矿作为载体除了自身有着较多的酸性位点,其内部的稀土元素(Ce,La,Nd)以及部分过渡金属元素等均可以协同所负载的Mn参与氧化循环的反应,有利于催化活性的提高。 展开更多
关键词 氟碳铈精矿 工艺矿物学 低温nh_(3)-scr 脱硝 稀土
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Mn/Zr改性稀土尾矿催化剂NH_(3)-SCR脱硝机理分析 被引量:2
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作者 焦坤灵 焦晓云 +3 位作者 刘佳杰 李娜 侯丽敏 武文斐 《中国环境科学》 EI CAS CSCD 北大核心 2023年第11期5655-5662,共8页
采用溶胶凝胶法制备了Mn、Mn/Zr负载稀土尾矿的NH_(3)-SCR催化剂,通过催化剂活性评价系统,结合H_(2)-TPR、NH_(3)-TPD、XRD和DRIFT研究了催化剂脱硝过程和反应机理.结果表明:Mn、Mn/Zr改性稀土尾矿催化剂的脱硝活性显著增强,在200℃时6%... 采用溶胶凝胶法制备了Mn、Mn/Zr负载稀土尾矿的NH_(3)-SCR催化剂,通过催化剂活性评价系统,结合H_(2)-TPR、NH_(3)-TPD、XRD和DRIFT研究了催化剂脱硝过程和反应机理.结果表明:Mn、Mn/Zr改性稀土尾矿催化剂的脱硝活性显著增强,在200℃时6%Mn1%Zr/稀土尾矿催化剂脱硝活性可达96%.改性后催化剂表面氧空位、B酸性位点及吸附物种数量明显增加,催化剂还原峰面积增大,其氧化还原性能的提升是活性提高的主要原因.催化剂B酸位NH_(4)^(+)与气态NO_(2)的反应遵循E-R机理,NH_(4)^(+)与单齿、双齿硝酸盐物种的反应遵循L-H机理. 展开更多
关键词 稀土尾矿 Mn、Zr改性 催化剂 nh_(3)-scr 脱硝机理
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稀土尾矿催化剂 NH_(3)-SCR脱硝SO_(2)耐受和机制研究 被引量:2
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作者 焦坤灵 汪思瀛 +2 位作者 焦晓云 刘佳铭 武文斐 《中国稀土学报》 EI CAS CSCD 北大核心 2023年第6期1051-1060,I0001,共11页
稀土尾矿制备 NH_(3)-SCR脱硝催化剂可实现资源高值化利用,SO_(2)耐受性是评价催化剂脱硝性能的关键指标之一。通过球磨、微波焙烧处理白云鄂博稀土尾矿得到稀土尾矿催化剂,采用脱硝性能实验结合BET, SEM&EDS和XRD分析了催化剂 NH_(... 稀土尾矿制备 NH_(3)-SCR脱硝催化剂可实现资源高值化利用,SO_(2)耐受性是评价催化剂脱硝性能的关键指标之一。通过球磨、微波焙烧处理白云鄂博稀土尾矿得到稀土尾矿催化剂,采用脱硝性能实验结合BET, SEM&EDS和XRD分析了催化剂 NH_(3)-SCR脱硝SO_(2)耐受性,基于 NH_(3)-TPD和FT-IR进一步分析SO_(2)耐受过程,构建SO_(2)耐受机制方程式探讨了SO_(2)耐受关键步骤。结果表明:稀土尾矿催化剂SO_(2)耐受性良好,催化剂在脱硝前后的形貌、结构和化学组成较为稳定;催化剂表面SO_(2)吸附转化后S_(2)O_(7)^(2-)基团的生成和反应是提高催化剂脱硝性能的关键,增加了催化剂表面弱酸和中强酸酸性位点,增强了催化剂 NH_(3)吸附能力,并促进了还原物种-NH_2和NH_4~+的生成,从而提高了稀土尾矿催化剂脱硝性能,该机制遵循L-H机制和E-R机制共同作用。 展开更多
关键词 稀土尾矿催化剂 nh_(3)-scr SO_(2)耐受机制 催化剂活性
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