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low-temperature SCR activity and SO2 deactivation mechanism of Ce-modified V2O5–WO3/TiO2 catalyst

Progress in Natural Science:Materials International 2015年第4期25卷 342-352页

作者： Ziran Ma Xiaodong Wu Ya Feng Zhichun Si Duan Weng Lei Shi The Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua University National Institute of Clean-and-low-Carbon Energy(NICE) Advanced Materials Institute Graduate School at ShenzhenTsinghua University Redbud Innovation Institute

The promotion effect of ceria modi fi cation on the low-temperature activity of V2O5-WO3/TiO2 catalyst was evaluated for the selective catalytic reduction of NO with NH3(NH3-SCR). The catalytic activity of 1 wt% V2O5-WO3/TiO2 was signi fi cantly enhanced by the addition of 8 wt%ceria, which exhibited a NO x conversion above 80% in a broad temperature range 190–450 1C. This performance was comparable with 3 wt%V2O5-WO3/TiO2, indicating that the addition of ceria contributed to reducing the usage of toxic vanadia in developing low-temperature SCR catalysts. Moreover, V1 Ce WTi exhibited approximately 10% decrease in NOx conversion in the presence of 60 ppm SO2. The characterization results indicated that active components of V, W and Ce were well dispersed on TiO2 support. The synergetic interaction between Ce and V species by forming V–O–Ce bridges enhanced the reducibility of VCe WTi catalyst and thus improved the low-temperature activity. The sulfur poisoning mechanism was also presented on a basis of the designed TPDC(temperature-programmed decomposition) and TPSR(temperatureprogrammed surface reaction) experiments. The deposition of(NH4)2SO4on V1 Ce WTi catalyst was much smaller compared with that on V1 *** the other hand, the oxidation of SO2 to SO3was signi fi cantly promoted on the CeO2-modi fi ed catalyst, accompanied by the formation of cerium sulfates. Therefore, the deactivation of this catalyst was mainly attributed to the vanishing of the V–Ce interaction and the sulfation of active ceria.

关键词： V2O5-WO3/TiO2 Ceria NH3-SCR low-temperature activity SO2 poisoning

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Enhancement in activity of a Vanadium Catalyst for the Oxidation of Sulfur Dioxide by Radio Frequency Plasma During the Preparation Process

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Journal of Natural Gas Chemistry 2003年第3期12卷 195-200页

作者： Zhenxing Chen, Honggui Li, Lingsen WangState Key Laboratory for Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China State Key Laboratory for Powder Metallurgy College of Chemistry and Chemical Engineering Central South University

Radio frequency plasma was used to prepare a vanadium catalyst. The resultsshowed that activating time of the catalyst could be shortened quickly and the catalytic activitywas improved to some extent with the use of plasma. Catalyst Ls-9 was prepared under an optimalcondition of 40 W discharge power, 10 min discharge time and 8 Pa gas pressure. The catalyticactivity was up to 54.7% at 410℃, which was 2.2% higher than that of the Ls-8 catalyst. Only 10 minwas needed to activate the catalyst with plasma, which was 1/9 of the traditional calcination *** Ls-9, both the endothermic as well as the exothermic peaks detected by differential thermalanalysis shifted to higher temperatures obviously, indicating that its crystal phase could melteasily. There existed an apparent endothermic peak at 283℃. SEM photographs showed a uniform sizedistribution. It is inferred that the quadrivalent vanadium compound may exist mainly in the form ofVOSO_4.

关键词： plasma activation dispersion vanadium catalyst low-temperature activity

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Structures and catalytic performances of Me/SAPO-34(Me=Mn,Ni,Co)catalysts for low-tem perature SCR of NO_x by ammonia

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Journal of Environmental Sciences 2021年第6期33卷 137-149页

作者： Xuesong Liu Zhiming Sui Hongfeng Chen Yong Chen Haigang Liu Peng Jiang Zhongyun Shen Wensheng Linghu Xiaodong Wu College of Chemistry and Chemical Engineering Shaoxing UniversityShaoxing 312000China Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Zhejiang Hailiang Eco.Mater.Co. Ltd.Zhuji 311814China Shaoxing Testing Institute of Quality and Technical Supervision Shaoxing 312000China Chemical Design and Research Institute of Qinghai Province Xining 810008China

Me/SAPO-34(Me=Mn,Ni,Co)series of catalysts were prepared by a wetness impregnation method and investigated for the selective catalytic reduction of nitrogen oxides with ammonia(NH 3-SCR).Among them,Mn/SAPO-34 catalyst was found as the most promising candidate based on its superior low-temperature *** catalysts were characterized by X-ray diffraction(XRD),transmission electron microscopy images(TEM),nuclear magnetic resonance(NMR),X-ray photoelectron spectroscopy(XPS),temperature programmed reduction and desorption(TPR and TPD),and diffuse reflectance infrared Fourier transformed spectroscopy(DRIFTS)of NH_(3)/NO_(x)***/SAPO-34 is obviously different from Ni/SAPO-34 and Co/SAPO-34 in the active species state and *** MnO_(x)species which play an essential role in NO oxidation and NO_(2)adsorption,act as better active sites than nickel and cobalt mostly in the form of the aluminates and silicates.

关键词： SAPO-34 Transition metals low-temperature activity Fast SCR Surface species

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Deactivation induced by metal sulfate over MnCeOx catalyst in NH_(3)-SCR reaction at low temperature

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Journal of Rare Earths 2024年第6期42卷 1056-1065,I0002页

作者： Qiao Xie Dongqi An Linsen Zhou Tingzhen Li Zhenghua Hu Menghan Chen Menglan Ma Lei Zhang Jingfang Sun Lin Dong School of Environmental and Chemical Engineering Chongqing Three Gorges UniversityChongqing404000China Key Laboratory of Water Environment Evolution and Pollution Control in the Three Gorges Reservoir Chongqing Three Gorges UniversityChongqing.404000China Jiangsu Key Laboratory of Vehicle Emissions Control Center of Modern AnalysisSchool of EnvironmentNanjing UniversityNanjing210093China Institute of Materials China Academy of Engineering PhysicsMianyang621908China

Sulfate adsorption is one of the factors that cause the poisoning of catalyst in the low-temperature NH_(3) selective catalytic reduction reaction(NH_(3)-SCR).In this paper,by controlling the co-adsorption time of SO_(2) and O_(2) at 150℃,a range of sulfated MnCeOx catalysts with different contents of metal sulfate species were prepared to reveal the influence of metal sulfate species content on the catalytic performances and reaction mechanisms at low *** catalytic activity below 250℃rapidly decreases with increasing metal sulfate species *** results of characterizations shed light on the reduction of specific surface area,Mn^(4+)and Ce^(3+)content,and redox ability of MnCeOx owing to the formation of metal sulfate *** experiments reveal that metal sulfate species preferentially absorb on MnOx domains rather than on CeO_(2) domains,and the adsorbed metal sulfate species can suppress the Eley-Rideal and the Langmuir-Hinshelwood reaction mechanisms over the sulfated *** the above results are detrimental to the activity of sulfated MnCeOx in the low-temperature NH3-SCR reaction.

关键词： NH_(3)selective catalytic reduction MnCeOx catalyst Sulfation low-temperature activity SO_(2)poisoning Rare earths

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low-temperature deNO_(x)performance and mechanism:a novel FeVO_(4)/CeO_(2)catalyst for iron ore sintering flue gas

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Journal of Iron and Steel Research International 2024年第9期31卷 2110-2121页

作者： Long Ding He-xi Zhao Ke Cheng Li-xin Qian Peng-yu Qi Qi Shi Hong-ming Long School of Metallurgical Engineering Anhui University of TechnologyMa’anshan243002AnhuiChina Key Laboratory of Metallurgical Emission Reduction and Resources Recycling(Anhui University of Technology) Ministry of EducationMa’anshan243002AnhuiChina Engineering Technology Training Center Nanjing Vocational University of Industry TechnologyNanjing21000JiangsuChina

Developing deNO_(x)catalysts with lower activity temperatures range significantly reduces NH_(3)selective catalytic reduction(SCR)operating costs for low-temperature industrial flue ***,a novel FeVO_(4)/CeO_(2)catalyst with great low-temperature NH_(3)-SCR and nitrogen selectivity was synthesized using a dipping *** techniques such as X-ray diffraction,Raman spectroscopy,specific surface and porosity analysis,H2 temperature-programmed reduction,NH_(3)temperature-programmed desorption,X-ray photoelectron spectroscopy,and the in situ diffused reflectance infrared Fourier transform spectroscopy were used to investigate the catalytic *** appropriate addition for FeVO_(4)in the catalyst was 5 wt.%from the results,and the active substance content reached the maximum dispersal capacity of the *** NO_(x)conversion exceeded 90%,and the nitrogen selectivity was more than 98%over this catalyst at 200–350℃.The activity was kept at 88%after 7.5 h of reaction at 200℃ for 7.5 h in 35 mg m^(-3)SO_(2)*** remarkable deNO_(x)activity,nitrogen selectivity,and sulphur resistance performances are attributed to the low redox temperature,the abundance of medium-strong acid and strong acid sites,the sufficient adsorbed oxygen,and the superior Fe^(2+)content on the *** Langmuir–Hinshelwood mechanism was observed on the FeVO_(4)/CeO_(2)catalyst in the NH_(3)selective catalytic reduction of NO_(x).

关键词： FeVO_(4)/CeO_(2)catalyst NH_(3)-SCR deNO_(x) low-temperature activity Langmuir-Hinshelwood mechanism

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Modification of Ni/SiO_2 Catalysts by Means of a Novel Plasma Technology

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Plasma Science and Technology 2008年第5期10卷 551-555页

作者：李育亮刘改焕宋磊储伟戴晓雁印永祥 Department of Chemical Engineering Sichuan UniversityChengdu 610065China

Atmospheric high frequency cold plasma jet was applied to modify Ni/SiO2 catalysts. The catalysts prepared by two different methods with plasma jet were compared with conventional catalysts. BET, XRD, H2-TPD and high-resolution transmission electron microscopy （HRTEM） were used to characterize these catalysts. The results showed that the catalyst prepared with plasma jet had higher nickel dispersion, larger specific surface area and smaller nickel particle size, about 5 nanometres. Detailed analyses revealed that improved structure and characteristic of the plasma catalyst were benefited from the large amount of hydrogen atoms in the plasma jet, by which the catalyst reduction can be easily achieved in shorter period of time at lower temperature, thus avoiding sintering and conglomeration of the active particles and the support. The activity of catalysts was investigated in the methane reforming with CO2. It is shown that the conversions of CH4 and CO2, the yields of H2 and CO were all significantly increased for the plasma catalysts.

关键词： plasma-reduced nickel-based catalyst silica gel support low-temperature activity methane reforming with carbon dioxide

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Enhancing low-temperature NH_(3)-SCR performance of Fe-Mn/CeO_(2)catalyst by Al_(2)O_(3)modification

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Journal of Rare Earths 2022年第9期40卷 1454-1461,I0005页

作者： Lulu Li Jiawei Ji Wei Tan Wang Song Xin Wang Xiaoqian Wei Kai Guo Wanyu Zhang Changjin Tang Lin Dong School of Environmental and Chemical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210093China Jiangsu Key Laboratory of Vehicle Emissions Control School of EnvironmentCenter of Modern AnalysisNanjing UniversityNanjing 210093China School of Environment Nanjing Normal UniversityNanjing 210093China

In the work,supported catalysts of FeO_(x) and MnO_(x) co-supported on aluminum-modified CeO_(2)was synthesized for low-temperature NH_(3)-selective catalytic reduction(NH_(3)-SCR)of ***,the SCR activity of the obtained catalyst is markedly influenced by the adding amount of Al and the appropriate Ce/Al molar ratio is 1/*** activity tests demonstrate that Fe-Mn/Ce1 Al2 catalyst shows over 90%NO conversion at 75-250℃and exhibits better SO_(2)resistance compared to Fe-Mn/CeO_(2).Fe-Mn/Ce1 Al2 shows the expected physicochemical characters of the ideal catalyst including the larger surface and increased active reaction active sites by controlling the amount of Al ***,the better catalytic activity is well correlated with the present advantaged surface adsorption oxygen species,Mn^(4+)species,Ce^(3+)species and the enhanced reducibility of Fe-Mn/Ce1 Al2,which is superior to the Fe-Mn/CeO_(2)*** importantly,we further demonstrate that the amount and strength of surface acid sites are improved by Al-doping and more active intermediates(monodentate nitrate)is generated during NH_(3)-SCR *** work provides certain insight into the rational creation of simple and practical denitration catalyst environmental purification.

关键词： Selectivity catalytic reduction NO removal low-temperature activity Al doping Cerium dioxide Rare earths

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