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Influence of sulfuric-acid-bath pretreatment and soaked in sulfuric acid on surface morphology and photocatalytic activity of titania coatings

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Science China(Technological Sciences) 2020年第12期63卷 2657-2663页

作者： GUAN SuJun HAO Liang KASUGA Shota YOSHIDA Hiroyuki cheng YanLing LU Yun Department of Physics Tokyo University of ScienceTokyo 162-8601Japan College of Mechanical Engineering Tianjin University of Science and TechnologyTianjin 300222China Department of Mechanical Engineering Chiba UniversityChiba 263-8522Japan Chiba Industrial Technology Research Institute Chiba 263-0016Japan Beijing Key Laboratory of Biomass Waste Resource Utilization Beijing Union UniversityBeijing 100023China

Titania(TiO2) photocatalyst coatings have been fabricated by the low-cost approach of sulfuric-acid-bath pretreatment(SAP)followed soaked in sulfuric acid(SA) at room temperature then oxidated in air. The influence of the SAP and soaked conditions on the surface morphology and photocatalytic activity of TiO2 on Ti coatings was investigated. With different SAP conditions,the surface morphologies of the TiO2 on Ti coatings clearly show the formed porous-like structure. With higher SA concentration,the porous-like structure becomes obviously. With extending soaked time,the porous-like structure tends to disappear. Raman spectroscopy reveals that the formed TiO2 coatings are with mixed-phase of anatase and rutile. Compared with those of SA concentration and SAP time,the influence of the soaked time on the phase transformation is obvious. Notably,the photocatalytic activity of TiO2 on Ti coatings had been efficiently enhanced by extending the soaked time,compared with those of higher SA concentration and longer SAP time. The enhanced photocatalytic activity of TiO2 on Ti coatings could be related with the changed surface morphology,mixed-phase of anatase and rutile,and formed hydroxyl groups.

关键词： TiO2 coatings sulfuric-acid-bath pretreatment mixed-phase photocatalytic activity surface morphology

single-atom Cu anchored on N-doped graphene/carbon nitride heterojunction for enhanced photocatalytic H_(2)O_(2) production

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Journal of Materials Science & Technology 2023年第30期161卷 192-200页

作者： Han Li Bicheng Zhu Bei cheng Guoqiang Luo Jingsan Xu Shaowen Cao State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Laboratory of Solar Fuel Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430078China School of Chemistry and Physics Queensland University of TechnologyBrisbaneQLD 4000Australia

Photocatalytic production of H_(2)O_(2) by polymeric carbon nitride has been regarded as a promising ap-proach for the conversion of solar energy into valuable ***,the efficiency of pristine car-bon nitride is limited by the rapid charge recombination and the lack of suitable active ***,we introduce single-atom Cu anchored on N-doped graphene(Cu-NG)as a cocatalyst coupled with carbon nitride via covalent bonding to enhance photocatalytic H_(2)O_(2) *** Cu-NG/carbon nitride could broaden the light absorption from UV to near-infrared region,contributing to the photocatalytic ***,NG containing electron-rich N atoms could serve as anchoring sites for stabilizing single-atom ***,the single-atom Cu acts not only as an electron sink to steer the interfacial charge sep-aration but also as an active site for molecular oxygen adsorption and *** the synergistic effect of the enhanced interfacial charge separation and suitable active sites,Cu-NG/carbon nitride ex-hibits improved photocatalytic performance with an H_(2)O_(2) generation rate of 2856μmol g^(−1)h^(−1),which is 2.6 times that of pristine carbon *** work provides a protocol for high-performance photocat-alytic H_(2)O_(2) production using a single-atom cocatalyst.

关键词： single-atom catalysis Interfacial charge separation Photocatalytic H_(2)O_(2)production

Regulating the oxidation state of Pd to enhance the selective hydrogenation for 5-hydroxymethylfurfural

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Chinese Journal of Chemical Engineering 2024年第8期72卷 60-68页

作者： Xin Li Yue Ma Xuning Wang Jianguo Wu Dong Cao Daojian cheng State Key Laboratory of Organic-Inorganic Composites and College of Chemical Engineering Beijing University of Chemical TechnologyBeijing 100029China

The highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran is an important reaction in the field of biomass hydrogenation,because it is a bridge between biomass resources and chemical ***,we precisely constructed carbon nitride supported Pd-based catalysts by a simple impregnation-reduction *** changing the reduction temperature,catalysts with different oxidation state could be precisely ***,the important correlation between the ratio of Pd^(0)/Pd^(2+)and catalytic activity is revealed during the selective hydrogenation of *** Pd/g—C_(3)N_(4)—300 catalyst with a Pd^(0)/Pd^(2+)ratio of 3/2 showed the highest catalytic activity,which could get 96.9%5-hydroxymethylfurfural conversion and 90.3%2,5-dihydroxymethylfuran *** density functional theory calculation revealed that the synergistic effect between Pd0and Pd2+in Pd/g—C_(3)N_(4)—300 system could boost the adsorption of the substrate and the dissociation of *** this work,we highlight the important correlation between metal oxidation state and catalytic activity,which provides valuable insights for the rational design of precious metal catalysts for hydrogenation reactions.

关键词： Pd/g-C_(3)N_(4) Selective hydrogenation 5-hydroxymethylfurfural 2,5-dihydroxymethylfuran Oxidation state

A Novel Braking Control Strategy for Hybrid Electric Buses Based on Vehicle Mass and Road Slope Estimation

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 340-350页

作者： Zijun Liu Shuo cheng Jinzhao Liu Qiong Wu Liang Li Huawei Liang State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China Beijing Forestry University Beijing 100091China University of Science and Technology Hefei 230026China Institute of Applied Technology Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230088China

Proper braking force distribution strategies can improve both stability and economy performance of hybrid electric vehicles,which is prominently proved by many *** achieve better dynamic stable performance and higher energy recovery efficiency,an effective braking control strategy for hybrid electric buses(HEB)based on vehicle mass and road slope estimation is proposed in this ***,the road slope and the vehicle mass are estimated by a hybrid algorithm of extended Kalman filter(EKF)and recursive least square(RLS).Secondly,the total braking torque of HEB is calculated by the sliding mode controller(SMC),which uses the information of brake intensity,whole vehicle mass,and road ***,comprehensively considering driver’s braking intention and regulations of the Economic Commission for Europe(ECE),the optimal proportional relationship between regenerative braking and pneumatic braking is ***,related simulations and experiments are carried out on the hardware-in-the-loop test *** show that the proposed strategy can effectively improve the braking performance and increase the recovered energy through precise control of the braking torque.

关键词： Hybrid electric bus Vehicle mass estimation Road slope estimation Braking control strategy Regenerative braking

In-situ conversion growth of carbon-coated MoS_(2)/N-doped carbon nanotubes as anodes with superior capacity retention for sodium-ion batteries

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Journal of Materials Science & Technology 2022年第7期102卷 8-15页

作者： Yadong Liu cheng Tang Weiwei Sun Guanjia Zhu Aijun Du Haijiao Zhang Institute of Nanochemistry and Nanobiology Shanghai UniversityShanghai 200444China School of Chemistry Physics and Mechanical EngineeringScience and Engineering FacultyQueensland University of TechnologyBrisbaneQLD 4001Australia School of Environmental and Chemical Engineering Shanghai UniversityShanghai 200444China

Layered structure MoS_(2) nanosheets have shown great potential for energy storage ***,the methodology for elaborately controllable growth of MoS_(2) onto carbonaceous matrix for promoting the electrochemical performance is highly ***,a high-effective,all-in-one in-situ conversion growth strategy has been proposed to construct a stable sandwich-type *** formation of the optimized C-MoS_(2)/NCNTs product undergoes a dissolution-recrystallization process,in which ultra-thin carbon layer-coated MoS_(2) nanosheets densely assembled onto the surface of polyimide(PI)derived N-doped carbon nanotubes(CNTs).Theoretical simulation reveals that MoS_(2) nanosheets possessing an expanded interlayer spacing of 0.92 nm can greatly reduce the barrier energy of Na ions ***-cordingly,the as-made C-MoS_(2)/NCNTs anode delivers superior cycling stability(82%capacity retention after 400 cycles at 1 A g^(−1))and rate performance(348 mAh g^(−1) at 2 A g^(−1)).The results demonstrate that the expanded MoS_(2) interlayer distance,ultrathin outer carbon coating,and N-doped CNTs matrix together accounts for the outstanding sodium storage capability for the C-MoS_(2)/NCNTs electrode.

关键词： MoS_(2)nanosheets In-situ conversion Carbon coating Expanded interlayer spacing Sodium-ion batteries

Heat transfer and flow structure of two-dimensional thermal convection over ratchet surfaces

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Journal of Hydrodynamics 2021年第5期33卷 970-978页

作者： cheng Wang Lin-feng Jiang He-chuan Jiang Chao Sun Shuang Liu Center for Combustion Energy Key Laboratory for Thermal Science and Power Engineering of Ministry of EducationDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of Engineering Mechanics School of Aerospace EngineeringTsinghua UniversityBeijing 100084China Yau Mathematical Sciences Center Tsinghua UniversityBeijing 100084China

This paper presents a numerical study of the Rayleigh-Benard convection(RBC)in two-dimensional cells with asymmetric(ratchet)roughness distributed on the top and bottom *** consider two aspect ratios of roughness y=1,... 详细信息

关键词： Turbulent convection ratchet roughness heat transfer flow structure

Room temperature phosphorescence achieved by aromatic/perfluoroaromatic interactions

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Science China Chemistry 2022年第5期65卷 918-925页

作者： Qunhua Zhang Yuanyuan Fan Qiuyan Liao cheng Zhong Qianqian Li Zhen Li Hubei Key Lab on Organic and Polymeric Opto-Electronic Materials Sauvage Center for Molecular SciencesDepartment of ChemistryWuhan UniversityWuhan 430072China Institute of Molecular Aggregation Science Tianjin UniversityTianjin 300072China

Room temperature phosphorescence(RTP) has attracted much attention for the applications in information encryption,bioimaging,displaying,and so *** this work,persistent RTP emission is mainly achieved by the compact face-to-face packing modes with aromatic/perfluoroaromatic ***,it can be further optimized by halogen substitutions with heavy atom effect,electron-withdrawing property,and steric hindrance,resulting in the prolonged RTP ***,the multiple fluorine substitutions endowed these luminogens with the water-resistant property,resulting in the maintained RTP emission with water ***,the aromatic/perfluoroaromatic interactions are not only the efficient approach to achieve persistent RTP,but also extend their application to a humid environment or even in water.

关键词： room temperature phosphorescence aromatic/perfluoroaromatic interaction face-to-face packing

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Heterostructure design of MOFs derived Co_(9)S_(8)/FeCoS_(2)/C composite with efficient microwave absorption and waterproof functions

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Journal of Materials Science & Technology 2022年第34期129卷 15-26页

作者： Runrun cheng Yan Wang Xiaochuang Di Zhao Lu Ping Wang Xinming Wu School of Materials and Chemical Engineering Xi’an Technological UniversityXi’an 710021China

At present, the problem of electromagnetic wave(EMW) pollution is critical, and the design of highperformance absorbers is of great significance. Based on the synergy between dielectric and magnetic losses, and between multicomponents in heterostructures, the development of light-weight absorbers with a strong absorption capability and multiple scattering is a promising strategy to achieve highperformance absorbers. In this work, CoFe-MOF precursors with a bouquet-like structure were prepared via the hydrothermal method, and Co_(7)Fe_(3)/C and Co_(9)S_(8)/FeCoS_(2)/C composites were obtained through a carbonization and sulfuration treatment during the high-temperature pyrolysis process, respectively. The experimental and theoretical results show that the Co_(9)S_(8)/FeCoS_(2)/C composite has a better EMW absorption performance, and its optimal reflection loss(RL) value is-53.9 d B at a low filler loading of 20 wt.%,which is due to the S doping that enhances the interface polarization relaxation process and improves the impedance matching characteristics. Moreover, the Co_(9)S_(8)/FeCoS_(2)/C composite can be as candidates of high-efficiency absorbers in extreme application environments.

关键词： Electromagnetic absorption Metal-organic frameworks(MOFs) Bouquet-like CoFe-MOF Sulfur doping

Enhance the activity of multi-carbon products for Cu via P doping towards CO_(2) reduction

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Science China Chemistry 2021年第7期64卷 1096-1102页

作者： Xiangdong Kong cheng Wang Han Zheng Zhigang Geng Jun Bao Jie Zeng Hefei National Laboratory for Physical Sciences at the Microscale Key La boratory of Strongly-Coupled Quantum Matter Physics of Chinese Academy of SciencesKey Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesDepartment of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230026China

Electronic structure engineering is a powerful method to tailor the behavior of adsorbed intermediates on the surface of catalysts,thus regulating catalytic activity towards CO_(2)***,we prepared a series of P-doped Cu catalysts for CO_(2)electroreduction into multi-carbon(C_(2+))products by regulating the surface electronic structure of *** introduction of P could stabilize the surface Cu^(δ+)species,enhancing the activity for C_(2+)products via adjusting the adsorbed strength of the CO intermediates(~*CO).When the molar ratio of P to Cu was 8.3%,the catalyst exhibited a Faradaic efficiency of 64%for C_(2+)products,which was 1.9 times as high as that(33%)for Cu catalysts at the applied current density of 210 m A cm^(-2).Notably,at the applied current density of 300 mA cm^(-2),the P-doped Cu catalyst with the molar ratio of P to Cu of 8.3%exhibited the highest partial current density for C_(2+)products of 176 mA cm^(-2),whereas the partial current density for C_(2+)products over the Cu catalyst was only 84 mA cm^(-2).Mechanistic studies revealed that modulating the molar ratios of P to Cu regulated the adsorbed strength of~*CO.A moderate adsorbed strength of *CO induced by appropriate P doping was responsible for the facilitated C–C coupling process.

关键词： P-doped Cu catalysts C^(2+)products ~*CO adsorption CO_(2)electroreduction