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A novel insight into enhanced propane combustion performance on PtUSY catalyst

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Rare Metals 2017年第1期36卷 1-9页

作者： Hui Luo Xiao-Dong Wu Duan Weng Shuang Liu rui ran State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China The Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua University Beijing 100084 China

Platinum was supported on c-AlOand ultrastable Y zeolite(USY) by an incipient wetness impregnation method. The catalysts were characterized by nitrogen physisorption, transmission electron microscopy(TEM),CO/CHisothermal oxidations, NHtemperature-programmed desorption(NH–TPD) and infrared(IR) spectroscopy of adsorbed probe molecules(CO, CHand CH+ O). Compared with Pt/AlO, Pt USY catalyst shows obviously higher activity for the combustion of propane. After estimating the size effect of Pt particles and propane adsorption capacity of USY, the excellent activity of Pt USY is also attributed to the strong interactions between the precious metal and the acidic zeolite. It inhibits the oxidation of Pt in an oxygen-rich atmosphere at high temperatures, which facilitate the initial oxidation step involving the C–H bond activation on metallic Pt as reflected by in situ diffuse reflectance infrared Fouriertransformed(DRIFT) spectra.

关键词： Platinum Zeolite Propane combustion Adsorption Metallic state Acidity

Highly effective La-deficient La1-xCexMnO3 mixed oxides for the complete oxidation of methane

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Progress in Natural Science:Materials International 2021年第3期31卷 373-378页

作者： Jiancai Ding rui ran Jingbo Jia Duan Weng Zhigang Yang Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University Beijing Key Laboratory of Energy Environmental Catalysis Beijing University of Chemical Technology

La-deficient LaCeMnOmixed oxides, obtained by selective dissolution in 1 M nitric acid, were employed in methane complete oxidation. The majority of the La cations in these perovskites were removed, resulting in increased specific surface areas, better reducibility and greater activity. Incorporation of a small amount of Ce stabilized the structure and a perovskite phase persisted in La-deficient LaCeMnOmixed oxides after 12 h of acid dissolution. LaCeMnOafter the acid treatment exhibited satisfactory catalytic activity, with T50 and T90 values of 365 and 459℃, respectively, which was even comparable to that previously reported 1% Pd/AlOcatalysts. And it showed excellent long-term activity even in the presence of COand HO.

关键词： LaMnO 3 Perovskite Selective acid dissolution Methane oxidation

Comparative study of La(1-x)CexMnO(3+δ) perovskites and Mn-Ce mixed oxides for NO catalytic oxidation

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Journal of Rare Earths 2020年第8期38卷 863-872,I0002页

作者： Baohuai Zhao rui ran Liu Yang Xiaodong Wu Zhichun Si Duan Weng Institute of Engineering Technology SINOPEC Catalyst CompanyBeijing 101111China Key Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Advanced Materials Institute Graduate School at ShenzhenTsinghua UniversityShenzhen 518055China

A series of La1-xCexMnO3+δ(x=D,0.05,0.1,0.2,and 0.3)perovskites and Mn-Ce mixed oxides were *** physico-chemical properties were systematically characterized and the NO oxidation activities of the catalysts were *** La0.9Ce0.1MnO3+δhas the best activity among all of the catalysts,with a maximum NO conversion of 85%at 300℃.The characterization results indicate that the doping of Ce improves the properties of the perovsidtes in terms of the specific surface area,the average valence state of Mn ions,the number of reactive oxygen species and the NOx desorption *** Mn-Ce mixed oxide calcined at 500℃shows a similar NO oxidation activity with La0.9Ce0.1MnO3+δ.However,the activity of the mixed oxide obtained at 750℃decreases a lot,which results from the loss of active sites and active oxygen species.

关键词： NO oxidation La1-xCexMnO3+δ Mn-Ce mixed Oxide NOx desorption Thermal stability Rare earths

Progress on metal-support interactions in Pd-based catalysts for automobile emission control

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Journal of Environmental Sciences 2023年第3期125卷 401-426页

作者： Yidan Cao rui ran Xiaodong Wu Zhichun Si Feiyu Kang Duan Weng Institute of Materials Research Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Tsinghua-Berkeley Shenzhen Institute Tsinghua UniversityShenzhen 518055China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

The interactions between metals and oxide supports,so-called metal-support interactions(MSI),are of great importance in heterogeneous ***-based automotive exhaust control catalysts,especially Pd-based three-way catalysts (TWCs),have received considerable research attention owing to its prominent oxidation activity of HCs/CO,as well as excellent thermal *** Pd-based TWCs,the dispersion,chemical state and thermal stability of Pd species,which are crucial to the catalytic performance,are closely associated with interactions between metal nanoparticles and their supporting *** on the research about MSI and utilization of MSI in advanced Pd-based three-way catalysts are reviewed *** with the development of advanced synthesis approaches and engine control technology,the study on MSI would play a notable role in further development of catalysts for automobile exhaust control.

关键词： Palladium Three-way catalysts(TWCs) Metal-support interaction Oxide supports

Deactivation of Cu-SAPO-34 by urea-related deposits at low temperatures and the regeneration

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Journal of Environmental Sciences 2019年第7期31卷 43-51页

作者： Yue Ma Xiaodong Wu Junyu Zhang rui ran Zhichun Si Duan Weng The Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and Engineering Tsinghua University School of Environment Tsinghua University Graduate School at Shenzhen Tsinghua University

Selective catalytic reduction(SCR) with urea catalyzed by Cu-SAPO-34 is an effective method to eliminate NO_x from diesel exhaust. However, urea-related deposits may form during cold-start and urban driving due to low exhaust temperatures. The activity of CuSAPO-34 at 175°C is significantly degraded by urea exposure, and 300°C is required for regeneration. Through in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) and temperature-programmed hydrolysis studies, the dominant stable deposit at 175°C is identified as biuret, which can be eliminated at 300°C. The urea-derived deactivation and regeneration mechanisms of Cu-SAPO-34 were compared with those of anatase-supported catalysts.

关键词： SCR Urea Biuret Cu-SAPO-34 Deactivation

Application of silica-alumina as hydrothermally stable supports for Pt catalysts for acid-assisted soot oxidation

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Rare Metals 2023年第5期42卷 1614-1623页

作者： Shu-ran Liu Shu-Ting Luo Xiao-Dong Wu Tao-Jin Wang rui ran Duan Weng Zhi-Chun Si Shuang Liu Key Laboratory of Advanced Materials of Ministry of Education of China School of Materials Science and EngineeringTsinghua UniversityBeijing100084China International Graduate School at Shenzhen Tsinghua UniversityShenzhen518055China School of Materials Science and Engineering Ocean University of ChinaQingdao266100China

In this work,silica-alumina mixed oxides with different SiO_(2)contents(5%and 30%)were adopted as acidic supports for platinum catalysts for soot *** obtained catalysts were hydrothermally aged in 10%H_(2)0/air at 750℃for 20 *** catalysts were characterized by X-ray diffraction(XRD),N_(2)adsorption,inductively coupled plasma(ICP),CO chemisorption,NH3temperature-programmed desorption(TPD),infrared(IR)spectroscopy of CO adsorption,temperature-programmed oxidation(TPO)of NO,and TPD of NO_(x).The surface acidity of catalyst was positive correlated with the content of SiO_(2),which kept platinum in metallic and partially oxidized states in an oxidizing *** with sulfation treatment on the alumina support,the application of SiO_(2)-Al_(2)O_(3)mixed oxides does not result in the coverage of Pt active sites and the prepared catalysts exhibit excellent activity for NO *** promote NOxpreferential adsorption on soot and decomposition of surface oxygenated compounds(SOCs)as the sulfated Pt/Al_(2)O_(3)catalyst does.

关键词： Platinum Acidic support Diesel soot Hydrothermal aging

ZrO2-supported α-MnO2:Improving low-temperature activity and stability for catalytic oxidation of methane

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Progress in Natural Science:Materials International 2018年第3期28卷 296-300页

作者： Jingbo Jia rui ran ruiqi Guo Xiaodong Wu Duan Weng Key Laboratory of Advanced Materials (MOE) School of Materials Science and EngineeringTsinghua University School of Transportation Science and Engineering Beihang University State Key Laboratory of New Ceramic and Fine Processing School of Materials Science and EngineeringTsinghua University

The single phaseα-Mn O2and in-situ supportedα-Mn O2/Zr O2with different ratios of Mn/Zr were synthesized by one-pot hydrothermal *** showed superior activity for catalytic oxidation of methane and even better than that of 1%Pt/*** T50of Mn O2/Zr O2catalysts with different ratios of Mn/Zr were located in the range of 315–335°C at a WHSV of 90 L g-1h-1,whereas that of Pt/Al2O3was 380°*** sulfur ageing,the Mn O2/Zr O2catalysts with Mn/Zr ratio of 2:1(2Mn O2/1Zr O2)and 1:1(1Mn O2/1Zr O2)exhibited satisfying sulfur resistance in comparison to the pure Mn *** 2Mn O2/1Zr O2catalyst also showed acceptable catalytic stability,and the addition of 10 vol%CO2had no obvious negative effect on its stability,whereas the addition of2.6 vol%H2O caused slight but reversible decreasing methane oxidative activity.

关键词： MnO2 ZrO2 support Methane oxidation Sulfur tolerance Stability

Size effect of Pt nanoparticles in acid-assisted soot oxidation in the presence of NO

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Journal of Environmental Sciences 2020年第8期32卷 64-71页

作者： Shuting Luo Xiaodong Wu Baofang Jin Shuang Liu rui ran Zhichun Si Duan Weng Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Graduate School at Shenzhen Tsinghua UniversityShenzhen 518055China

Pt/Al2O3 catalysts with mean Pt particle size ranged from 2.7 to 7.1 nm were synthesized by chemical reduction method,and the sulfated counterparts were prepared by impregnation of sulfuric *** turnover frequency of platinum for soot oxidation under loose contact conditions in a feed flow containing NO and O2 are positively correlated with the size of *** sulfated Pt/Al2O3 exhibits higher catalytic activity for soot oxidation in the presence of NO despite their reduced ability for NO2 *** a contradiction is more significant for those catalysts with smaller platinum ***,the catalysts were characterized by X-ray diffraction(XRD),Brunauer-Emmett-Teller(BET),transmission electron microscopy(TEM),inductive coupled plasma(ICP)emission spectrometry,CO chemisorption,thermogravimetric analysis(TGA),NH3 temperature-programmed desorption(NH 3-TPD),NO temperature-programmed oxidation(TPO)and NO x temperatureprogrammed desorption(TPD).Possible effect of Pt particle size for the catalytic oxidation of soot in the presence of NO was presented based primarily on the promoted NO2 transfer efficiency onto the soot pushed by the acidic catalysts.

关键词： Pt/Al2O3 Sulfation Soot oxidation Particle size effect NO 2 transfer

Controlled pore size of Pt/KIT-6 used for propane total oxidation

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Rare Metals 2018年第2期37卷 123-128页

作者： Yu-Sheng Chen Yi-Dan Cao rui ran Xiao-Dong Wu Duan Weng Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua University State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University

Mesoporous silica KIT-6 with different pore sizes was controllably synthesized by hydrothermal meth- ods. The same contents of Pt were loaded on KIT-6 sup- ports to apply for propane total oxidation. Low-angle X-ray diffraction （XRD）, nitrogen adsorption-desorption, CO chemisorption and transmission electron microscopy （TEM） were carried out to investigate the physicochemical properties of the catalysts. The results reveal that different pore sizes of KIT-6 supports could affect the Pt particle sizes on KIT-6. The mesopores on KIT-6-80 and KIT-6- 130 effectively confine the size of the inside Pt nanopar- ticles during calcining. Pt/KIT-6-80 with the appropriate pore size as well as the Pt particle size exhibits the best catalytic performance with T50 （the temperature at which hydrocarbon （HC） conversion reaches 50%） of only 237 ℃. However, Pt particles prefer dispersing on the external surface of KIT-6-40 due to those too small pores.

关键词： Mesoporous silica KIT-6 Pore size Propanetotal oxidation