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Influence of NO_(x) on the activity of Pd/θ-Al_(2)O_(3) catalyst for methane oxidation: Alleviation of transient deactivation

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Journal of Environmental Sciences 2022年第2期34卷 38-47页

作者： Chang Cui Yan Zhang Wenpo Shan Yunbo Yu Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Ningbo Research Center for Urban Environment Chinese Academy of SciencesNingbo 315800China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China

Alumina supported Pd catalyst(Pd/Al_(2)O_(3)) is active for complete oxidation of methane, while often suffers transient deactivation during the cold down process. Herein, heating and cooling cycle tests between 200 and 900 ℃ and isothermal experiments at 650 ℃ were conducted to investigate the influence of NO_(x) on transient deactivation of Pd/θ-Al_(2)O_(3) catalyst during the methane oxidation. It was found that the co-fed of NO alleviated transient deactivation in the cooling ramp from 800 to 500 ℃, which was resulted from the in situ formation of NO_(2) during the process of methane oxidation. Over the Pd/θ-Al_(2)O_(3), thermogravimetric analysis and O_(2) temperature programmed oxidation measurements confirmed that transient deactivation was due to the decomposition of Pd O particles and the hysteresis of Pd reoxidation, while the metal Pd entities were less active for methane oxidation than the Pd O ones. CO pulse chemisorption and scanning transmission electron microscopy characterizations rule out the NO_(2) effect on Pd size change. Powder X-ray diffraction and X-ray photoelectron spectroscopy characterizations were used to obtain palladium status of Pd/θ-Al_(2)O_(3) before and after reactions, indicating that in lean conditions at 650 ℃, the presence of NO_(2) increases the content of active Pd O on the catalyst surface, thus benefits methane oxidation. Homogeneous reaction between CH 4, O_(2), and NO_(x) may be partially responsible for the alleviation above 650 ℃. The interesting research of alleviation in transient deactivation by NO_(x), the components co-existing in exhausts, are of great significance for the application.

关键词： Methane Catalytic oxidation Palladium NO_(x)influence

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Shape dependence of support for NO_x storage and reduction catalysts

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Journal of Environmental Sciences 2019年第1期31卷 396-407页

作者： Wen Xie Yunbo Yu Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of Sciences University of Chinese Academy of Sciences Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences

Pt/BaO/Al_2O_3 catalysts with different BaO loadings prepared from Al_2O_3 nanorods(Pt/BaO/Al_2O_3-nr) and irregular Al_2O_3 nanoparticles(Pt/BaO/Al_2O_3-np) were investigated for NOx storage and reduction(NSR). The Pt/BaO/Al_2O_3 materials derived from Al_2O_3 nanorods always exhibited much higher NOx storage capacity(NSC) over the whole temperature range of 100–400°C than the corresponding Pt/BaO/Al_2O_3-np samples containing the same BaO loading, giving the maximum NSC value of 966.9 μmol/gcatat 400°C, 1.4 times higher than that of Pt/BaO/Al_2O_3-np. Higher catalytic performance of nanorod-supported NSR samples was also observed during lean-rich cyclic conditions(90 sec vs. 5 sec), giving more than 98% NOx conversion at 300–450°C over the Pt/BaO/Al_2O_3-nr sample with 15% BaO loading. To reveal this dependence on the shape of the support during the NSR process, a series of characterization techniques including the Brunauer–Emmett–Teller(BET) method,X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), H_2 temperature programmed reduction(H2-TPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) were also conducted. It was found that intimate contact of Ba–Al and Ba–Pt sites was achieved over the Pt/BaO/Al_2O_3 surface when using Al_2O_3-nr as a support.This strong interaction among the multi-components of Pt/BaO/Al_2O_3-nr thus triggered the formation of surface nitrite and nitrate during the lean period, and also accelerated the reverse spillover of ad-NOxspecies onto the Pt surface, enhancing their reduction and leading to high NSR performance.

关键词： NOx storage and reduction Pt/BaO/Al2O3 Nanorod Morphology effect Strong interaction

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Efficient Pt/KFI zeolite catalysts for the selective catalytic reduction of NOxby hydrogen

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Journal of Environmental Sciences 2024年第4期138卷 102-111页

作者： Ligang Zhang yulong Shan Zidi Yan Zhongqi Liu Yunbo Yu Hong He School of Rare Earths University of Science and Technology of ChinaHefei 230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341119China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

Aiming at purification of NO_(x)from hydrogen internal combustion engines(HICEs),the hydrogen selective catalytic reduction(H_(2)-SCR)reaction was investigated over a series of Pt/KFI zeolite catalysts.H_(2)can readily reduce NO_(x)to N_(2)and N_(2)O while O_(2)inhibited the deNO_(x)efficiency by consuming the reductant H_(2).The Pt/KFI zeolite catalysts with Pt loading below 0.1wt.% are optimized H_(2)-SCR catalysts due to its suitable operation temperature window since high Pt loading favors the H_(2)-O_(2)reaction which lead to the insufficient of reactants.Compared to metal Pt^(0)species,Pt^(δ+)species showed lower activation energy of H_(2)-SCR reaction and thought to be as reasonable active sites.Further,Eley-Rideal(E-R)reaction mechanism was proposed as evidenced by the reaction orders in kinetic studies.Last,the optimized reactor was designed with hybrid Pt/KFI catalysts with various Pt loading which achieve a high NO_(x)conversion in a wide temperature range.

关键词： Pt/KFI zeolite Pt loading H_(2)-SCR Reaction conditions Kinetics studies

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Investigation of the common intermediates over Fe-ZSM-5 in NH 3-SCR reaction at low temperature by in situ DRIFTS

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Journal of Environmental Sciences 2020年第8期32卷 32-39页

作者： Xiaoyan Shi Yingjie Wang yulong Shan Yunbo Yu Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

The surface species formed in the reaction of NO and NO2 with pre-adsorbed NH 3 over a Fe-ZSM-5 catalyst(1.27 wt.%Fe,SiO2/Al2O3=25)at low temperature(140°C)were studied by in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS).Through using a background spectrum of NH3-saturated Fe-ZSM-5,we clearly observed the formation of common intermediates resulting from the reaction of NO2 or NO+O2 with pre-adsorbed NH3.This presents strong evidence that the oxidation of NO to form surface nitrates and nitrites is the key step for standard SCR at low temperature.In addition,the results suggest that in the SCR reaction at low temperature,the NH^4+ions absorbed on Brønsted acid sites are less active than NH3 adsorbed on Lewis acid sites related to Fe species.

关键词： Fe-ZSM-5 NH 3-SCR SCR mechanism Intermediates In situ DRIFTS

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Alkali resistance promotion of Ce-doped vanadium-titanic- based NH3-SCR catalysts

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Journal of Environmental Sciences 2018年第11期30卷 155-161页

作者： Zidi Yan Xiaoyan Shi Yunbo Yu Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China University of Chinese Academy of Sciences Beijing 100049 China Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China

The effect of K deactivation on V2OJWO3-TiO2 and Ce-doped V2O5/WO3-TiO2 catalysts in the selective catalytic reduction （SCR） of NOx by NH3 was studied. Ce-doped V2O5/WO3-TiO2 showed significantly higher resistance to K deactivation than V2O5/WO3-TiO2. Ce-doped V2O5/WO3-TiO2 with K/V = 4 （molar ratio） showed 90% NOx conversion at 350℃, whereas in this case V2O5/WO3-TiO2 showed no activity. The fresh and K-poisoned V2O5/WO3-TiO2 and Ce-doped V2O5/WO3-TiO2 catalysts were investigated by means of in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）, NH3-temperature progress decomposition （NH3-TPD）, X-ray photoelectron spectroscopy （XPS） and H2-temperature program reduction （H2-TPR）. The effect of Ce doping on the improving resistance to K of V2O5/WO3- TiO2were discussed.

关键词： Selective catalytic reduction Ammonia Nitrogen oxides V2O5/WO3-TiO2 Alkali deactivation

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Theoretical and experimental study on the inhibition of jet fuel oxidation by diarylamine

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Chinese Journal of Chemical Engineering 2023年第4期56卷 225-232页

作者： Tinghao Jia Yunbo Yu Qing Liu Yao Yang Ji-Jun Zou Xiangwen Zhang Lun Pan Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou 311200China Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

Antioxidants addition is believed as a facile and effective way to improve jet fuel thermal oxidation stability.However,amine antioxidants,as one of the most important antioxidants,have not received sufficient attention in the field of jet fuel autoxidation yet.Herein,the inhibition efficiency and mechanism of decane and exo-tetrahydrodicyclopentadiene(THDCPD)oxidation by di-4-tert-butylphenylamine(diarylamine)was experimentally and theoretically investigated.The results show that diarylamine can significantly inhibit decane oxidation but is less efficient for THDCPD oxidation,which is attributed to the higher energy barrier of retro-carbonyl-ene reaction(rate-determining step)in THDCPD than that in decane during diarylamine regeneration.However,the addition of diarylamine will cause undesirable color change after accelerated oxidation and produce slightly more deposits during high-temperature thermal oxidative stress for both decane and THDCPD.The results provide significant implications for the future design of effective antioxidant additives for high-performance jet fuel.

关键词： Jet fuel Thermal oxidation stability High-energy-density fuel Diarylamine Antioxidation mechanism

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An artificial intelligence-aided design (AIAD) of ship hull structures

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Journal of Ocean Engineering and Science 2023年第1期8卷 15-32页

作者： yu Ao yunbo Li Jiaye Gong Shaofan Li College Of Shipbuilding Engineering Harbin Engineering UniversityChina Department of Civil and Environmental Engineering University of CaliforniaBerkeleyCA 94720USA College of Ocean Science and Engineering Shanghai Maritime UniversityChina

Ship-hull design is a complex process because the any slight local alteration in ship hull structure may significantly change the hydrostatic and hydrodynamic performances of a ship.To find the optimum hull shape under the design requirements,the state-of-art of ship hull design combines computational fluid dynamics computation with geometric modeling.However,this process is very computationally intensive,which is only suitable at the final stage of the design process.To narrow down the design parameter space,in this work,we have developed an AI-based deep learning neural network to realize a real-time prediction of the total resistance of the ship-hull structure in its initial design process.In this work,we have demonstrated how to use the developed DNN model to carry out the initial ship hull design.The validation results showed that the deep learning model could accurately predict the ship hull’s total resistance accurately after being trained,where the average error of all samples in the testing dataset is lower than 4%.Simultaneously,the trained deep learning model can predict the hip’s performances in real-time by inputting geometric modification parameters without tedious preprocessing and calculation processes.The machine learning approach in ship hull design proposed in this work is the first step towards the artificial intelligence-aided design in naval architectures.

关键词： Artificial intelligence Deep learning neural network Hull deformation Machine learning Ship hull design Total resistance

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Robust Nonsingular Fixed Time Terminal Sliding Mode Control for Atmospheric Pollution Detection Lidar Scanning Mechanism

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Journal of Systems Science & Complexity 2023年第2期36卷 500-523页

作者： KANG yu YANG yuxiao CHEN Cai LüWenjun ZHAO yunbo Department of Automation University of Science and Technology of ChinaHefei 230027China Institute of Advanced Technology University of Science and Technology of ChinaHefei 230027China State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230027China

A robust nonsingular fixed time terminal sliding mode control scheme with a time delay disturbance observer is proposed for atmospheric pollution detection lidar scanning mechanism(APDL-SM)system.Distinguished from the conventional terminal sliding mode control methods,the authors design a novel fixed-time terminal sliding surface,the convergence time of sliding mode phase of which has a constant upper bound that is designable by adjusting only one parameter.Moreover,in order to overcome the problem of unknown upper bound of lumped uncertainty including model uncertainty,friction effect and external disturbances from the port environment,the authors propose a time delay disturbance observer to provide an estimation for the system lumped uncertainty.By using the Lyapunov synthesis,the explicit analysis of the convergence time upper bound are performed.Finally,simulation studies are conducted on the APDL-SM system to show the fast convergence rate and strong robustness of the proposed control scheme.

关键词： Atmospheric pollution detection lidar fixed time terminal sliding mode time delay disturbance observer tracking control

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Design of Ca-type todorokite catalysts with highly active for the selective reduction of NO_(x) by NH_(3) at low temperatures

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Journal of Environmental Sciences 2024年第4期138卷 697-708页

作者： Chuang Chang Zidi Yan Chunlei Zhang Yanshuang Zhang Miao Jiang Luna Ruan Min Xiao Yunbo Yu Hong He School of Rare Earths University of Science and Technology of ChinaHefei 230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

Ca-type todorokite catalysts were designed and prepared by a simple redox method and applied to the selective reduction of NO_(x) by NH_(3)(NH_(3)-SCR)for the first time.Compared with the Na-type manjiroite prepared by the same method,the todorokite catalysts with different Mn/Ca ratios showed greatly improved catalytic activity for NO_(x) reduction.Among them,Mn8Ca4 catalyst exhibited the best NH_(3)-SCR performance,achieving 90%NO_(x) conversion within temperature range of 70-275℃ and having a high sulphur resistance.Compared to the Na-type manjiroite sample,Ca-type todorokite catalysts possessed an increased size of tunnel,resulting in a larger specific surface area.As increased the amounts of Ca doping,the Na content in Ca-type todorokite catalysts significantly decreased,providing larger amounts of Bronsted acid sites for NH_(3) adsorption to produce NH_(4)^(+).The NH_(4)^(+)species were highly active for reaction with NO+O_(2),playing a determining role in NH_(3)-SCR process at low temperatures.Meanwhile,larger amounts of surface adsorbed oxygen contained over the Ca-doping samples than that over Na-type manjiroite,promoting the oxidation of NO and fast SCR processes.Over the Ca-type todorokite catalysts,furthermore,nitrates produced during the flow of NO+O_(2),were more active for reaction with NH_(3) than that over Na-type manjiroite,benefiting the occurrence of NH_(3)-SCR process.This study provides novel insights into the design of NH_(3)-SCR catalysts with high performance.

关键词： NO_(x) NH_(3)-SCR Mn-based oxides Ca-type todorokite Bronsted acid sites

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Self-Tuning Asynchronous Filter for Linear Gaussian System and Applications

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IEEE/CAA Journal of Automatica Sinica 2018年第6期5卷 1054-1061页

作者： Wenjun Lv yu Kang yunbo Zhao Department of Automation University of Science and Technology of ChinaHefei 230027China State Key Laboratory of Fire Science Department of Automation and Institute of Advanced TechnologyUniversity of Science and Technology of ChinaHefei 230027China Key Laboratory of Technology in GeoSpatial Information Processing and Application System Chinese Academy of SciencesBeijing 100190China College of Information Engineering Zhejiang University of TechnologyHangzhou 310023China

In this paper, optimal filtering problem for a class of linear Gaussian systems is studied. The system states are updated at a fast uniform sampling rate and the measurements are sampled at a slow uniform sampling rate. The updating rate of system states is several times the sampling rate of measurements and the multiple is constant. To solve the problem,we will propose a self-tuning asynchronous filter whose contributions are twofold. First, the optimal filter at the sampling times when the measurements are available is derived in the linear minimum variance sense. Furthermore, considering the variation of noise statistics, a regulator is introduced to adjust the filtering coefficients adaptively. The case studies of wheeled robot navigation system and air quality evaluation system will show the effectiveness and practicability in engineering.

关键词：最优滤波噪声统计量机器人自动化系统

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