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化学链重整反应中含氧空位α-Fe_(2)O_(3)(001)表面CO反应行为的密度泛函理论研究

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Chinese Journal of Chemical Physics 2024年第1期37卷 116-124,I0112-I0116,I0119页

作者：张慧欣黄正清班涛苏雪杨伯伦常春然西安交通大学化学工程与技术学院陕西省能源化工过程强化重点实验室西安710049 榆林学院化学与化工学院陕西省低变质煤洁净利用重点实验室榆林719000

化学链甲烷重整是利用甲烷制备合成气(CO和H_(2))具有广阔前景的方法之一,其中CO在氧载体表面上的进一步反应对CO选择性起主要决定作用.本文采用密度泛函理论系统地研究了α-Fe_(2)O_(3)(001)氧空位对CO脱附、CO氧化和CO解离的影响.计... 详细信息

化学链甲烷重整是利用甲烷制备合成气(CO和H_(2))具有广阔前景的方法之一,其中CO在氧载体表面上的进一步反应对CO选择性起主要决定作用.本文采用密度泛函理论系统地研究了α-Fe_(2)O_(3)(001)氧空位对CO脱附、CO氧化和CO解离的影响.计算结果表明,增加氧空位浓度会导致Fe原子中的电子局域化增强,从而削弱Fe位点上CO的脱附能力.此外,氧空位浓度从1/12 ML增加到1/6 ML会导致CO氧化能垒从0.64 eV增加到1.10 eV.增加氧空位浓度虽有利于CO解离,但由于解离反应的高能垒(大于3.00 eV),CO的解离仍然很难发生.综合考虑三条反应途径,CO脱附可以在高于900K的反应温度下自发进行.增加氧空位浓度可以提高合成气选择性,因为在高氧空位浓度(1/6 ML)下,相比于CO脱附,CO氧化的竞争性减弱.这项研究揭示了在Fe_(2)O_(3)的还原程度增加时,化学链甲烷重整中CO选择性增强的微观机制.

关键词：化学链重整甲烷 Fe_(2)O_(3) 氧空位密度泛函理论

Theoretical Investigations of the Catalytic Role of Water in Propene Epoxidation on Gold Nanoclusters： A Hydroperoxyl- Mediated Pathway

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Nano Research 2011年第1期4卷 131-142页

作者： chun-ran chang Yang-Gang Wang Jun Li Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education TsinghuaUniversity Beijing 100084 China

We report a comprehensive theoretical investigation of the catalytic reaction mechanisms of propene epoxidation on gold nanoclusters using density functional theory （DFT）. We have shown that water acts as a catalytic promoter for propene epoxidation on gold catalysts. Even without reducible supports, hydroperoxyl （OOH） and hydroxyl （OH） radicals are readily formed on small-size gold clusters from co-adsorbed H20 and 02, with energy barriers as low as 4-6 kcal/mol （1 cal = 4.186 J）. Propene epoxidation occurs easily through reactions between C3H6 and the weakened O-O bond of the OOH radicals on the surfaces of gold clusters.

关键词： Gold nanocluster propene epoxidation hydroperoxyl radical density functional theory

Hydrogenation of molecular oxygen to hydroperoxyl： An alternative pathway for O2 activation on nanogold catalysts

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Nano Research 2015年第11期8卷 3737-3748页

作者： chun-ran chang Zheng-Qing Huang Jun Li School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an 710049 China Department of Chemistry and Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education Tsinghuo University Beijing 100084 China

Activation of molecular O2 is the most critical step in gold-catalyzed oxidation reactions; however, the underlying mechanisms of this process remain under debate. In this study, we propose an alternative O2 activation pathway with the assistance of hydrogen-containing substrates using density functional theory. It is demonstrated that the co-adsorbed H-containing substrates （R-H） not only enhance the adsorption of O2, but also transfer a hydrogen atom to the adjacent O2, leading to O2 activation by its transformation to a hydroperoxyl （OOH） radical species. The activation barriers of the H-transfer from 16 selected R-H compounds （H2O, CH3OH, NH2CHCOOH, CH3CH=CH2, （CH3）2SiH2, etc.） to the co-adsorbed O2 are lower than 0.50 eV in most cases, indicating the feasibility of the activation of O2 via OOH under mild conditions. The formed OOH oxidant, with an increased O-O bond length of -1.45 A, either participates directly in oxidation reactions through the end-on oxygen atom, or dissociates into atomic oxygen and hydroxyl （OH） by crossing a fairly low energy barrier of 0.24 eV. Using CO oxidation as a probe, we have found that OOH has superior activity than activated O2 and atomic oxygen. This study reveals a new pathway for the activation of O2, and may provide insight into the oxidation catalysis of nanosized gold.

关键词： O2 activation gold cluster adsorption dissociation hydroperoxyl

Role of surface frustrated Lewis pairs on reduced CeO2(110)in direct conversion of syngas

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Chinese Journal of Catalysis 2020年第12期41卷 1906-1915页

作者： Zheng-Qing Huang Teng-Hao Li Bolun Yang chun-ran chang Shaanxi Key Laboratory of Energy Chemical Process Intensification School of Chemical Engineering and TechnologyXi’an Jiaotong UniversityXi’an 710049ShaanxiChina

Direct syngas conversion to light olefins on bifunctional oxide-zeolite(OX-ZEO)catalysts is of great interest to both academia and industry,but the role of oxygen vacancy(Vo)in metal oxides and whether the key intermediate in the reaction mechanism is ketene or methanol are still not *** address these two issues,we carry out a theoretical study of the syngas conversion on the typical reducible metal oxide,CeO2,using density functional theory *** results demonstrate that by forming frustrated Lewis pairs(FLPs),the VOs in CeO2 play a key role in the activation of H2 and *** activation of H2 on FLPs undergoes a heterolytic dissociative pathway with a tiny barrier of 0.01 eV,while CO is activated on FLPs by combining with the basic site(O atom)of FLPs to form CO2^2-.Four pathways for the conversion of syngas were explored on FLPs,two of which are prone to form ketene and the other two are inclined to produce methanol suggesting a compromise to resolve the debate about the key intermediates(ketene or methanol)in the *** constant calculations showed that the route initiating with the coupling of two CO*into OCCO*and ending with the formation of ketene is the dominant pathway,with the neighboring FLPs playing an important role in this ***,our study reveals the function of the surface FLPs in the activation of H2 and CO and the reaction mechanism for the production of ketene and methanol for the first time,providing novel insights into syngas conversion over OX-ZEO catalysts.

关键词： Syngas conversion Light olefins Oxide-zeolite Frustrated Lewis pairs CeO2

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Reaction Mechanism of One-Step Conversion of Ethanol to 1,3-Butadiene over Zn-Y/BEA and Superior Catalysts Screening

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Chinese Journal of Chemical Physics 2022年第4期35卷 600-610,I0004-I0009,I0149页

作者： Shu-Xuan Dang Han-Xuan Liu Tao Ban Xin Gao Zheng-Qing Huang Dong-Yuan Yang chun-ran chang Shaanxi Key Laboratory of Energy Chemical Process Intensification School of Chemical Engineering and TechnologyXi’an Jiaotong UniversityXi’an 710049China Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization School of Chemistry and Chemical EngineeringYulin UniversityYulin 719000China Shaanxi Yanchang Petroleum(Group)Corp.Ltd. Xi’an 710065China

The one-step conversion of ethanol to 1,3-butadiene has achieved a breakthrough with the development of beta zeolite supported dual metal ***,the reaction mechanism from ethanol to butadiene is complex and has not yet been fully elucidated,and no catalyst screening effort has been done based on central metal *** this work,density functional theory(DFT)calculations were employed to study the mechanism of one-step conversion of ethanol to butadiene over ZnY/BEA *** results show that ethanol dehydrogenation prefers to proceed on Zn site with a reaction energy of 0.77 eV in the rate-determining step,and the aldol condensation to produce butadiene prefers to proceed on Y site with a reaction energy of 0.69 eV in the rate-determining *** on the mechanism revealed,six elements were selected to replace Y for screening superior combination of Zn-M/BEA(M=Sn,Nb,Ta,Hf,Zr,Ti;BEA:beta polymorph A)for this *** a result,Zn-Y/BEA(0.69 eV)is proven to be the most preferring catalyst compared with the other six ones,and Zn-Zr/BEA(0.85 eV),Zn-Ti/BEA(0.87 eV),and Zn-Sn/BEA(0.93 eV)can be potential candidates for the conversion of ethanol to *** work not only provides mechanistic insights into one-step catalytic conversion of ethanol to butadiene over Zn-Y/BEA catalyst but also offers more promising catalyst candidates for this reaction.

关键词： Ethanol 1,3-Butadiene Zn-Y/BEA Aldol condensation Density functional theory

Activation of Molecular Oxygen via a Hydroperoxyl(OOH) Intermediate on Gold Catalysts

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Activation of Molecular Oxygen via a Hydroperoxyl(OOH) Inter...

Mechanical and damping performances of TPMS lattice metamaterials fabricated by laser powder bed fusion

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作者： chun-ran chang Jin-Cheng Liu Jun Li Institute of Industrial Catalysis School of Chemical Engineering and Technology Xi'an Jiaotong University Department of Chemistry Tsinghua University

Activation of molecular O is the most critical step in gold-catalyzed oxidation *** it is generally accepted that O is activated at the interface between Au nanoparticles and supports[1]or at the oxygen defects of reducible oxides[2],an overall understanding of the activation of O is still elusive due to the neglect of catalytic ***,the presence of co-adsorbates,including the reactants

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China Foundry 2024年第4期21卷 327-333页

作者： Yan-peng Wei Huai-qian Li Jing-jing Han Ying-chun Ma Hao-ran Zhou Jing-chang Cheng Jian Shi Zhi-quan Miao Bo Yu Feng Lin National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Space Physics Beijing 100076China

Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ***,its vibration and noise reduction,and damping properties have not been fully ***,in this study,the TPMS structures with parameterization were designed by the method of surface migration,and the TPMS structures with high forming quality was manufactured by laser powder bed fusion(LPBF).The mechanical properties and energy absorption characteristics of the beam and TPMS structures were studied and compared by quasi-static *** modal shapes of the beam lattice structures and TPMS structures were obtained by the free modal analysis,and the damping properties of two structures were obtained by modal *** the two structures after heat treatment with the same porosity of 70%,the yield strength of the beam lattice structure reaches 40.76 MPa,elastic modulus is 20.38 GPa,the energy absorption value is 32.23 MJ·m^(-3),the damping ratio is 0.52%.The yield strength,elastic modulus,energy absorption value,and damping ratio of the TPMS structure are 50.74 MPa,25.37 GPa,47.34 MJ·m^(-3),and 0.99%,*** results show that TPMS structures exhibit more excellent mechanical properties and energy absorption,better damping performance,and obvious advantages in structural load and vibration and noise reduction compared with the beam lattice structures under the same porosity.

关键词： lattice metamaterials TPMS energy absorption damping laser powder bed fusion

Advancements in machine learning for material design and process optimization in the field of additive manufacturing

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China Foundry 2024年第2期21卷 101-115页

作者： Hao-ran Zhou Hao Yang Huai-qian Li Ying-chun Ma Sen Yu Jian shi Jing-chang Cheng Peng Gao Bo Yu Zhi-quan Miao Yan-peng Wei National Key Laboratory of Advanced Casting Technologies Shenyang Research Institute of Foundry Co.Ltd.CAMShenyang 110022China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Space Physics Beijing 100076China School of Materials Science and Engineering Nanyang Technological University639798Singapore

Additive manufacturing technology is highly regarded due to its advantages,such as high precision and the ability to address complex geometric ***,the development of additive manufacturing process is constrained by issues like unclear fundamental principles,complex experimental cycles,and high *** learning,as a novel artificial intelligence technology,has the potential to deeply engage in the development of additive manufacturing process,assisting engineers in learning and developing new *** paper provides a comprehensive overview of the research and applications of machine learning in the field of additive manufacturing,particularly in model design and process ***,it introduces the background and significance of machine learning-assisted design in additive manufacturing *** then further delves into the application of machine learning in additive manufacturing,focusing on model design and process ***,it concludes by summarizing and forecasting the development trends of machine learning technology in the field of additive manufacturing.

关键词： additive manufacturing machine learning material design process optimization intersection of disciplines embedded machine learning

Effect of Platelet-rich Plasma in Stimulating Macrophage Transformation into M2 Type under AMPK Signaling Pathway

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Chinese Journal of Biomedical Engineering 2024年第02期33卷 85-92页

作者： ZHONG chang-rui FU chun-hua Longyan First Affiliated Hospital of Fujian Medical University The Second Hospital of Longyan

Objective: To explore the effect of platelet-rich plasma(RPR) in stimulating the transformation of pro-inflammatory(M1) macrophages into antiinflammatory(M2) under the adenosine-monophosphate-dependent protein kinase(AMPK) signaling pathway. Methods: Rat peritoneal macrophages(RAW264.7) were cultured and randomly divided into 8 groups: blank control group, LPS group, RPR group A, RPR group B, LPS+RPR(12 h) group, LPS+RPR(24 h) group A, LPS+RPR(24 h)group B, LPS+RPR(24 h) group C. RPR was prepared based on blood donors. The expressions of AMPK signaling pathway-related proteins(AMPK, ULK1, m TOR) and macrophage markers(i NOS, Arg-1) in the blank control group, LPS group, LPS+RPR(12 h)group and LPS+RPR(24 h) group were observed and compared. The expressions of macrophage markers in LPS+RPR(24 h) B and C groups were compared, and the expressions of AMPK and TGF-β in RPR A and B groups were compared. Results: The gray values of AMPK and ULK1 in LPS cells decreased significantly, while those in LPS+RPR(12 h) and LPS+RPR(24 h) A cells increased significantly. The gray values of AMPK and ULK1 in LPS+RPR(24 h) A cells were higher than those in LPS+RPR(12 h)cells(P<0.05). The m TOR gray value of LPS cells was significantly higher than that of LPS+RPR(24 h) A cells, and the m TOR gray value of LPS+RPR(24 h) A cells was significantly lower than that of LPS+RPR(12 h) cells(P<0.05). The expression of i NOS in LPS cells was significantly decreased, the expression of i NOS in LPS+RPR(12 h) and LPS+RPR(24 h) cells was significantly increased, and the expression of i NOS in LPS+RPR(24 h) cells was higher than that in LPS+RPR(12 h) cells(P<0.05). The expression of Arg-1 in LPS cells was significantly decreased, the expression of Arg-1 in LPS+RPR(12 h) and LPS+RPR(24 h) A cells was significantly increased, and the expression of Arg-1 in LPS+RPR(24 h) A cells was higher than that in LPS+RPR(12 h)cells(P<0.05). The i NOS expression level of LPS+PRP(24 h) C cells was significantly higher

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