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Journal of Materials Science & Technology 2023年第10期141卷 257-268页

作者： wenyao Sun Minghui chen Fuhui Wang Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang 110819China

Nanocrystalline coating with the same chemical composition as the nickel-based superalloys was proved to possess high resistance to oxidation and scale spallation,meanwhile avoid notable elements inter-diffusion.It opens up a new direction for the development of protective coatings.However,in a worse environment containing chlorine and water vapor,the ultrafine grains act like a double-edged sword,which can promote the formation of a protective scale of Al_(2)O_(3)or Cr_(2)O_(3),but also favor the inward dif-fusion of Cl and H_(2)O to accelerate corrosion.In order to solve this problem,moderate amount of oxygen was doped into nanocrystalline coating during magnetron sputtering.Then,corrosion behavior of the two nanocrystalline coatings with or without oxygen doping was studied in the O_(2)+38%H_(2)O environment with solid NaCl deposit.Results indicated that the doped oxygen can attract active elements of Ti and Al to form TiO_(2)andθ-Al_(2)O_(3),which pinned at grain boundaries to keep the ultrafine grains stable at high temperature while prevent inward diffusion of the corrosive media.Accordingly,a dense and pure chromia scale was formed quickly at surface,ensuring that the oxygen-doped nanocrystalline coating provided the highest corrosion resistance under the synergy of solid NaCl deposit and water vapor.In contrast,the coating without oxygen doping suffered from severe internal corrosion.

关键词： High-temperature corrosion Nickel-based superalloys Coatings Chlorination Water vapor

Effects of particle shape and packing style on ethylene oxidation reaction using particle-resolved CFD simulation

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Particuology 2023年第11期82卷 87-97页

作者： Yao Shi Hao chen Wenyao Chen Guanghua Ye Jin Qu Jinbing Li Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai200237China Yanshan Branch of Beijing Research Institute of Chemical Industry China Petroleum&Chemical Company(Sinopec Corp.)Beijing102500China

Gaining in-depth insights into the effects of particle shapes and packing style on ethylene oxidation reaction is of paramount industrial importance.In this work,reactor models of five packing structures with different particle shapes and three packing structures with different packing styles are established by employing software Blender and COMSOL Multiphysics to explore how the reaction-diffusion behaviors affect ethylene oxidation process.The reliabilities of rigid body dynamics model and particle-resolved reactor model are verified by comparing simulated and experimental pressure drops and ethylene conversions.In all the five packing structures with laminar flow conditions,the high bed porosity and low total particle surface area for the trilobe packing structure give rise to the lowest pressure drop of 27.8 Pa/m,while the internal voids cutting mode provides the excellent heat transfer capacity for the Raschig ring packing structure and the highest ethylene conversion and thereby the highest bed temperature rise of 25.1 K for the four-hole cylinder packing structure.Based on these analyses,changing the packing style to the bottom-up Raschig ring-four hole cylinder packing structure would be a good strategy for the effectively lowered reactor temperature rise by 4.8 K together with the slightly reduced ethylene conversion.

关键词： Ethylene oxidation Particle shape Packing style Heat transfer

Towards a molecular understanding of the electronic metal-support interaction(EMSI)in heterogeneous catalysis

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Green Energy & Environment 2023年第3期8卷 619-625页

作者： Keng Sang Ji Zuo Xiangxue Zhang Qianhong Wang Wenyao Chen Gang Qian Xuezhi Duan State Key Laboratory of Chemical Engineering East China University of Science and Technology130 Meilong RoadShanghai200237China

Tailoring the electronic metal-support interaction(EMSI)has attracted considerable interests as one of the most efficient approaches to improve both the activity and stability of metal catalysts in heterogeneous catalysis.In this viewpoint,we illustrate the methodology and relevant fundamentals on the disentanglement,characterization,and interpretation of EMSI.Under the choice of monometallic catalyst over inert support,a combination of optimal experiment design,multimodal techniques,in situ characterization,with a comprehensive understanding of the underlying measurement protocols is highly desirable for a reliable determination of EMSI.Accordingly,not only the d-band filling but also d-band energy within the EMSI should be taken into consideration for providing general principles to guide the electron-promoting catalytic reaction.

关键词： EMSI Disentanglement Characterization Interpretation d-band

Taming Electrons in Pt/C Catalysts to Boost the Mesokinetics of Hydrogen Production

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Engineering 2022年第7期8卷 124-133页

作者： Wenyao Chen Wenzhao Fu Xuezhi Duan Bingxu chen Gang Qian Rui Si Xinggui Zhou Weikang Yuan De chen State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai 201204China Department of Chemical Engineering Norwegian University of Science and TechnologyTrondheim N-7491Norway

Taming the electron transfer across metal–support interfaces appears to be an attractive yet challenging methodology to boost catalytic properties.Herein,we demonstrate a precise engineering strategy for the carbon surface chemistry of Pt/C catalysts—that is,for the electron-withdrawing/donating oxygencontaining groups on the carbon surface—to fine-tune the electrons of the supported metal nanoparticles.Taking the ammonia borane hydrolysis as an example,a combination of density functional theory(DFT)calculations,advanced characterizations,and kinetics and isotopic analyses reveals quantifiable relationships among the carbon surface chemistry,Pt charge state and binding energy,activation entropy/enthalpy,and resultant catalytic activity.After decoupling the influences of other factors,the Pt charge is unprecedentedly identified as an experimentally measurable descriptor of the Pt active site,contributing to a 15-fold increment in the hydrogen generation rate.Further incorporating the Pt charge with the number of Pt active sites,a mesokinetics model is proposed for the first time that can individually quantify the contributions of the electronic and geometric properties to precisely predict the catalytic performance.Our results demonstrate a potentially groundbreaking methodology to design and manipulate metal–carbon catalysts with desirable properties.

关键词： Mesokinetics model Catalyst descriptor Pt charge state Carbon surface chemistry Hydrogen generation activity

Kinetics and mechanistic insights into the active sites of Au catalysts for selective propylene oxidation

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Nano Research 2023年第5期16卷 6220-6227页

作者： Qianhong Wang Zhihua Zhang Keng Sang Wenyao Chen Gang Qian Jing Zhang Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Identification of the catalytically active sites emerges as the prerequisite for an atomic-level comprehensive understanding and further rational design of highly efficient catalysts.Here,we demonstrate a kinetics strategy to identify the active sites of Au catalyst for the disentanglement of geometric and electronic effects on the selective oxidation of propylene to acrolein.Both the Ti-containing titanium-silicalite-1(TS-1)and Ti-free silicalite-1(S-1)were employed as supports to immobilize Au catalysts,which were investigated by a combination of multiple characterization,kinetics analysis,crystal structure modelling.The Au(111)sites are identified as the main active site for acrolein formation,while their electronic effects are highly relevant to the presence or absence of Ti.Moreover,propylene epoxide(PO)formation mainly involves the co-participation of Au and Ti sites,the proximity between Au and Ti sites is found to have less influences on PO formation in a certain distance.In comparison,acrolein is very likely to generate over Au(111)sites via the hydrogen-assisted O_(2) activation to oxygenated species for its oxidizing propylene.The insights gained here could guide the design and preparation of Au catalysts for selective propylene oxidation.

关键词： propylene oxidation Au catalysts active site geometric and electronic effects Au-Ti proximity

Mechanistic insights into propylene oxidation to acrolein over gold catalysts

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Chinese Journal of Chemical Engineering 2023年第5期57卷 39-49页

作者： Bin Lin Wenyao Chen Nan Song Zhihua Zhang Qianhong Wang Wei Du Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

Direct epoxidation of propylene with H_(2)/O_(2),being the dream reaction for propylene oxide(PO)production,has raised wide scientific and industrial interests.Fundamentally understanding the formation mechanism of acrolein,as the main by-product of this epoxidation process,is very important to achieve the high yield of PO.In this study,we perform the spin-polarized density functional theory(DFT)calculations to investigate the reaction pathway from propylene to acrolein over two representative Au surfaces,that is,Au(111)and Au(100),which incorporates propylene adsorption,methyl hydrogen activation and acrolein formation.The results show that the oxygenated species(mainly O^(*),OH^(*)and OOH^(*))are able to stabilize the adsorption of propylene to decrease the energy barrier for its activation.It is demonstrated that the OOH^(*)on Au(111)surface emerges as the most easily formed oxygenated species via the H-assisted O_(2) dissociation,which is also the most active for the cleavage of methyl CAH bond in propylene.Furthermore,three pathways of acrolein formation activated by O^(*)/OH^(*)/OOH^(*)are analyzed,in which O^(*)is found as the key species to form acrolein.Finally,Bader charge analysis was conducted to explore the reasons behind the promotion effect of the oxygenated species.The insights reported here could be valuable in the design and optimization of gold catalysts for the direct epoxidation of propylene.

关键词： Acrolein formation Oxygenated species DFT calculations Au surfaces Reaction mechanism

Improving high-temperature wear resistance of NiCr matrix self-lubricating composites by controlling oxidation and surface texturing

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Journal of Materials Science & Technology 2022年第36期131卷 253-263页

作者： Xuan Kong wenyao Sun Qunchang Wang Minghui chen Tao Zhang Fuhui Wang Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang 110819China

Self-lubricating composites(SLCs)are widely used in the fields of aerospace and marine,but the conventional NiCr matrix SLCs with sulfide as solid lubricant often suffer from low wear resistance at high temperatures.In view of its high affinity with oxygen and also the high oxidation rate,appropriate amount of nano Ti was added to NiCr-WS_(2)composites prepared by spark plasma sintering(SPS)to adjust the oxidation behavior and surface texture.When exposed to high temperature,Ti was preferentially oxidized in comparison to Ni and Cr,resulting in abundant TiO_(2)protrusions and microdimples on the surface,i.***.in situ surface texturing.Besides,TiO_(2)was of high chemical activity and readily to react with other oxide debris during high temperature sliding process to form compounds of NiTiO_(3)and CrTi_(2)O_(5).The high chemical activity of oxide debris that was conducive to sintering,combining with the special surface texture that stores as many wear debris as possible,promoted the rapid formation of a protective glaze layer on the sliding surface.The NiCr-WS_(2)-Ti composite exhibited low friction coefficient but high wear resistance at elevated temperatures.Especially at 800℃,it presented a wear rate of as low as(2.1±0.3)×10^(-5)mm^3N-1m^(-1),accounting for only 2.7%of that of NiCr-WS_(2)composite.

关键词： Self-lubricating composites High temperature oxidation Glaze layer Surface texturing

Polyoxometalates-engineered hydrogen generation rate and durability of Pt/CNT catalysts from ammonia borane

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Journal of Energy Chemistry 2020年第2期29卷 142-148页

作者： Wenzhao Fu chen Han Dali Li Wenyao Chen Jian Ji Gang Qian Weikang Yuan Xuezhi Duan Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Department of Chemical Engineering and Applied Chemistry University of TorontoToronto.Ontario M5S 3E5Canada

Heterogeneously catalyzed hydrolytic dehydrogenation of ammonia borane is a remarkable structure sensitive reaction. In this work, a strategy by using polyoxometalates(POMs) as the ligands is proposed to engineer the surface and electronic properties of Pt/CNT catalysts toward the enhanced hydrogen generation rate and durability. Three kinds of POMs, i.e., silicotungstic acid(STA), phosphotungstic acid(PTA)and molybdophosphoric acid(PMA), are comparatively studied, among which the STA shows positive effects on the catalytic activity and durability. A catalyst structure-performance relationship is established by a combination of kinetic and isotopic analyses with multiple characterization techniques, such as HAADF-STEM, EDS, Raman spectroscopy and XPS. It is shown that the STA compared to the other two POMs can increase the Pt binding energy and thus promote the reaction. The insights demonstrated here could open a new avenue for boosting the reaction by employing the POMs as the ligands to engineer the catalyst electronic properties.

关键词： Polyoxometalates Pt/CNT Electronic properties Hydrogen generation Durability

Active sites of Pt/CNTs nanocatalysts for aerobic base-free oxidation of glycerol

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Green Energy & Environment 2020年第1期5卷 76-82页

作者： Minjian Pan Jingnan Wang Wenzhao Fu Bingxu chen Jiaqi Lei Wenyao Chen Xuezhi Duan De chen Gang Qian Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and Technology130 Meilong RoadShanghai200237China Department of Chemical Engineering Norwegian University of Science and TechnologyTrondheim7491Norway

Understanding the nature of Pt active sites is of great importance for the structure-sensitive base-free oxidation of glycerol. In the present work, the remarkable Pt particle size effects on glycerol conversion and products formation from the oxidation of the primary and the secondary hydroxyl groups are understood by combining the model calculations and DFT calculations, aiming to discriminate the corresponding dominant Pt active sites. The Pt(100) facet is demonstrated to be the dominant active sites for the glycerol conversion and the products formation from the two routes. The insights revealed here could shed new light on fundamental understanding of the Pt particle size effects and then guiding the design and optimization of Pt-catalyzed base-free oxidation of glycerol toward targeted products.

关键词： Base-free oxidation of glycerol Pt/CNTs catalyst Active sites Model calculations DFT calculations

Platelet carbon nanofibers as support of Pt-CoO electrocatalyst for superior hydrogen evolution

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Journal of Energy Chemistry 2021年第1期30卷 33-40,I0002页

作者： Jie Gan Zikun Huang Wei Luo Wenyao Chen Yueqiang Cao Gang Qian Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Exploration of cost-effective Pt/C catalysts has been a significant issue for electrochemical hydrogen evolution reaction(HER) toward sustainable energy conversion and storage.Herein,we report a fabrication strategy by employing platelet carbon nanofibers(p-CNF) as the support to immobilize Pt-CoO HER electrocatalyst using atomic layer deposition method.The edge-rich p-CNF support is found to act as the anchoring sites of Pt nanoparticles and favorably capture electrons from Pt to yield electron-deficient Pt surfaces for the boosted HER.Additionally,the sequential growth of CoO onto the Pt/p-CNF catalyst elaborately constructs the Pt-CoO interface and facilitates the electron transfer from Pt to CoO,which further enhances the HER activity.These advantages endow the fabricated Pt-CoO/p-CNF catalyst with the superior HER activity,e.g.,a very low overpotential of 26 mV at the current density of 10 mA·cm-2 and a mass activity of 4.42 A·mgPt-1at the overpotential of 30 mV,18.8 times higher than that of the commercial20 wt% Pt/C catalyst.The insights reported here could shed light on for the fabrication of cost-effective Pt-based composite HER catalysts.

关键词： Hydrogen evolution Electrocatalysts Platelet carbon nanofibers Pt-CoO catalyst Atomic layer deposition