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An Isolated Zinc–Cobalt Atomic Pair for Highly Active and Durable Oxygen Reduction

Angewandte Chemie 2019年第9期131卷

作者： Ziyang Lu Bo Wang Yongfeng Hu Wei Liu Yufeng Zhao Ruoou Yang Zhiping Li Jun Luo Bin Chi Zheng Jiang Minsi Li Shichun Mu Shijun Liao Jiujun Zhang Xueliang Sun Key Laboratory of Applied Chemistry in Hebei Province Yanshan University Qinhuangdao 066004 China Canadian Light Source 44 Innovation Boulevard Saskatoon SK S7N 2 V3 Canada Center for Electron Microscopy and Tianjin Key Lab of Advanced Functional Porous Materials Institute for New Energy Materials School of Materials Tianjin University of Technology Tianjin 300384 China Institute of Sustainable Energy/College of Science Shanghai University Shanghai 200444 P. R. China Shanghai Synchrotron Radiation Facility Chinese Academy of Sciences Shanghai 201204 China The Key Laboratory of Fuel Cell Technology of Guangdong Province South China University of Technology Guangzhou 510641 China Department of Mechanical and Materials Engineering University of Western Ontario London Ontario N6A 5B9 Canada Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

A competitive complexation strategy has been developed to construct a novel electrocatalyst with Zn‐Co atomic pairs coordinated on N doped carbon support (Zn/CoN‐C). Such architecture offers enhanced binding ability of O 2 , significantly elongates the O−O length (from 1.23 Å to 1.42 Å), and thus facilitates the cleavage of O−O bond, showing a theoretical overpotential of 0.335 V during ORR process. As a result, the Zn/CoN‐C catalyst exhibits outstanding ORR performance in both alkaline and acid conditions with a half‐wave potential of 0.861 and 0.796 V respectively. The in situ XANES analysis suggests Co as the active center during the ORR. The assembled zinc–air battery with Zn/CoN‐C as cathode catalyst presents a maximum power density of 230 mW cm −2 along with excellent operation durability. The excellent catalytic activity in acid is also verified by H 2 /O 2 fuel cell tests (peak power density of 705 mW cm −2 ).

关键词： Cobalt Isolierte Atompaare Sauerstoffreduktion Zn-Luft-Batterie

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Effect of CaO on Phase Separation and Properties in Na2O-CaO-SiO2-P2O5 Opaque Glass

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IOP Conference Series: materials Science and Engineering 2019年第1期562卷

作者： Lida Luo Zihao Li Qingwei Wang Kaidong Lan Weizhong Jiang State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Donghua University Shanghai 201620 People's Republic of China Engineering Research Center of Advanced Glass Manufacturing Technology Ministry of Education Shanghai 201620 People's Republic of China Shanghai Jingcai New Materials Co.Ltd Shanghai 201800 China

In the Na2O-CaO-SiO2-P2O5 opaque glass system, the effects of CaO on the phase separation and properties were investigated by means of SEM, XRD, UV-VIS Spectro Photometer, Thermal dilatometer, etc. The results showed the size of the second phases enriched with phosphate became smaller from 200nm to 80nm with the increase of CaO concentration. CaO had clear influence on the transmittance of opal glass, and the glass was changed into semi opaque when the amount of CaO was 12%. It also affected the crystallization of the glass samples, especially in crystal peak intensity of the Na3Ca6(PO4)5 and Zn2P2O7. the coefficient of thermal expansion of sample was reduced but the density increased with the increase of CaO concentration. Results showed that Calcium ions in Na2O-CaO-SiO2-P2O5 system was good to bind with the P ions and boost the separation of the second phase and the crystallization.

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Stimuli‐Responsive Reversible Switching of Intersystem Crossing in Pure Organic Material for Smart Photodynamic Therapy

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Angewandte Chemie 2019年第32期131卷

作者： Wenbo Hu Tingchao He Hui Zhao Haojie Tao Runfeng Chen Lu Jin Junzi Li Quli Fan Wei Huang Alexander Baev Paras N. Prasad Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing University of Posts & Telecommunications Nanjing 210023 China Institute for Lasers Photonics and Biophotonics and the Department of Chemistry University at Buffalo State University of New York Buffalo NY 14260 USA Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 211816 China College of Physics Science & Technology Shenzhen University Shenzhen 518060 China Shaanxi Institute of Flexible Electronics Northwestern Polytechnical University Xi'an 710072 China

Photosensitizers (PSs) with stimuli‐responsive reversible switching of intersystem crossing (ISC) are highly promising for smart photodynamic therapy (PDT), but achieving this goal remains a tremendous challenge. This study introduces a strategy to obtain such reversible switching of ISC in a new class of PSs, which exhibit stimuli‐initiated twisting of conjugated backbone. We present a multidisciplinary approach that includes femtosecond transient absorption spectroscopy and quantum chemical calculations. The organic structures reported show remarkably enhanced ISC efficiency ( Φ ISC ), switching from nearly 0 to 90 %, through an increase in the degree of twisting, providing an innovative mechanism to promote ISC. This leads us to propose here and demonstrate the concept of smart PDT, where pH‐induced reversible twisting maximizes the ISC rate, and thus enables strong photodynamic action only under pathological stimulus (such as change in pH, hypoxia, or exposure to enzymes). The ISC process is turned off to deactivate PDT ability, when the PS is transferred or metabolized away from pathological region.

关键词： Intersystem Crossing Photodynamische Therapie Photosensibilisatoren Ultraschnelle Spektroskopie

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Reversible phase transition induced large piezoelectric response in Sm-doped BiFeO3 with a composition near the morphotropic phase boundary

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Physical Review B 2017年第21期95卷 214101-214101页

作者： Zhenyu Liao Fei Xue Wei Sun Dongsheng Song Qiqi Zhang Jing-Feng Li Long-Qing Chen Jing Zhu National Center for Electron Microscopy in Beijing State Key Laboratory of New Ceramics and Fine Processing Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University Beijing 100084 People's Republic of China Department of Materials Science and Engineering The Pennsylvania State University University Park Pennsylvania 16802 USA State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 People's Republic of China

materials with the morphotropic phase boundary (MPB) exhibit an ultrahigh mechanical response to electrical inputs, which has been widely used in applications such as sensors and actuators. Recently, the rare-earth element doped BiFeO3 (BFO) was found to possess a MPB between a rhombohedral polar phase and an orthorhombic antipolar phase with enhanced piezoelectric response, enabling it to be an attractive alternative to toxic Pb-based piezoelectric materials. Despite theoretical and experimental efforts, the phase transition behavior under electric fields has not been directly confirmed, leaving a gap in the understanding of the origin of enhanced piezoelectricity. Here, we have demonstrated an irreversible electric-field induced phase transition from the antipolar phase to the polar phase in Sm-doped BFO with the pre-MPB composition, and a reversible phase transition between the polar phase and the antipolar/nonpolar phase in Sm-doped BFO with the MPB composition. In situ transmission electron microscopy technique combined with thermodynamic calculation based on the Ginzburg-Landau-Devonshire theory indicates that the electric-field induced reversible phase transition leads to enhanced piezoelectric response and double P-E hysteresis loops. These results provide us a deep insight into the mechanism of exotic electromechanical response in the rare-earth element doped BFO system with the composition near the MPB.

关键词： Ferroelectricity Piezoelectricity Thin films High-resolution transmission electron microscopy

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Preparation and properties of polyurethane films with spent coffee grounds

Preparation and properties of polyurethane films with spent ...

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Chinese materials Congress on Functional and Functionally Structured materials, CMC 2015

作者： Li, Rui Xue Shen, Xiao Lin Zhou, Yi Wang, Hao Jiang, Shan Xu, Wei Lin College of Textile Science and Engineering Wuhan Textile University Wuhan China State Key Laboratory of New Textile Materials and Advanced Technology Wuhan Textile University Wuhan China

ISBN: (纸本)9783038357605

In this study, a method of recycling spent coffee grounds (SCG) is introduced. The SCG was dried and crushed into micron-sized coffee particles. The coffee particles could be used to prepared polyurethane (PU) films with different contents (0wt.%, 5wt.%, 10wt.%, 15wt.%, 20wt.%, 25wt.% and 30wt.%). The anti-ultraviolet property, thermal comfort performance and mechanical property of different PU films were measured. The results showed that after the blending of coffee particles, the films exhibited excellent anti-ultraviolet property and thermal comfort performance, and the mechanical properties were also retained. This study also provided an effective approach to reuse SCG, which is consistent with the environmental-friendly society principle. © 2016 Trans Tech Publications, Switzerland.

关键词： Blending

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Mussel Byssus Cuticle: Metal Coordination-Mediated Functional Grading and Self-Healing in Mussel Byssus Cuticle (Adv. Sci. 23/2019)

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advanced Science 2019年第23期6卷 1970138-1970138页

作者： Quan Xu Meng Xu Chun-Yu Lin Qiang Zhao Rui Zhang Xiaoxiao Dong Yida Zhang Shouceng Tian Yu Tian Zhenhai Xia State Key Laboratory of Heavy Oil Processing Beijing Key Laboratory of Biogas Upgrading Utilization Harvard SEAS-CUPB Joint Laboratory on Petroleum Science College of New Energy and Materials Science China University of Petroleum-Beijing Beijing 102249 China Department of Orthopedics General Hospital of Chinese People's Liberation Army Beijing 100853 China Department of Materials Science and Engineering University of North Texas Denton TX 76203 USA School of Chemistry and Chemical Engineering Huazhong University of Science&Technology Wuhan 435000 China State Key Laboratory of Tribology Tsinghua University Beijing 100084 China

In article number https://***/10.1002/advs.201902043 , Quan Xu, Yu Tian, Zhenhai Xia, and co‐workers present how mussel cuticle is a functionally‐graded material with high stiffness, extensibility, and self‐healing capacity and oxygen absorbs on metal ions, weakening the iron‐catecholate bonds in the cuticle and collagen core, but this process can be reversed by sea water.

关键词： density functional theory iron complex mussels self-healing tensile tests

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Enhanced mechanical properties in Al/diamond composites by Si addition

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Rare Metals 2016年第9期35卷 701-704页

作者： Jian-Hua Wu Hai-Long Zhang Yang Zhang Jian-Wei Li Xi-Tao Wang Shandong Engineering Research Center for Lightweight Automobiles Magnesium Alloy New MaterialsShandong Academy of Sciences State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

Diamond particles reinforced aluminum–silicon matrix composites,abbreviated as Al（Si）/diamond composites,were fabricated by squeeze *** effect of Si content on the microstructure and mechanical properties of the composites were *** mechanical properties are found to increase monotonically with Si content increasing up to 7.0 wt%.The Al-7.0 wt% Si/diamond composite exhibits tensile strength of 78 MPa,bending strength of 230 MPa,and compressive strength of426 ***–Si eutectic phases are shown to connect with Al matrix and diamond particles tightly,which is responsible for the enhancement of mechanical properties in the Al（Si）/diamond composites.

关键词： Composite materials Diamond particles Mechanical properties Interfaces

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Photocatalytic Water Splitting: Phase and Defect Engineering of MoS2Stabilized in Periodic TiO2Nanoporous Film for Enhanced Solar Water Splitting (advanced Optical materials 5/2019)

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advanced Optical materials 2019年第5期7卷

作者： Limin Guo Caifu Zhong Li Shi Licheng Ju Xiaohui Wang Daquan Yang Ke Bi Yanan Hao Yang Yang State Key Laboratory of Information Photonics and Optical Communications School of Science Beijing University of Posts and Telecommunications Beijing 100876 China NanoScience Technology Center Department of Materials Science and Engineering University of Central Florida 4000 Central Florida Blvd. Orlando FL 32816 USA Energy Research Institute National Development and Reform Commission Beijing 100038 China State Key Laboratory of New Ceramics and Fine Processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

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Unravelling charge carrier dynamics in protonated g-C3N4 interfaced with carbon nanodots as co-catalysts toward enhanced photocatalytic CO2 reduction： A combined experimental and first-principles DFT study

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Nano Research 2017年第5期10卷 1673-1696页

作者： Wee-Jun Ong Lutfi Kurnianditia Putri Yoong-Chuen Tan Lling-Lling Tan Neng Li Yun Hau Ng Xiaoming Wen Siang-Piao Chai Institute of Materials Research and Engineering (IMRE) Agency for Science Technology and Research (A'STAR) 2 Fusionopolis Way Innovis Singapore 138534 Singapore Multidisciplinary Platform of Advanced Engineering Chemical Engineering Discipline School of Engineering Monash University Jalan Lagoon Selatan Bandar Sunway 47500 Selangor Malaysia Chemical Engineering School of Engineering and Physical Sciences Heriot-Watt University Jalan Venna PS/2 Precinct 5 62200 Putrajaya Malaysia State Key Laboratory of Silicate Materials for Architectures Wuhan University of Technology 122 Luoshi Road Wuhan 430070 China Particles and Catalysis Research Group (PARTCAT) School of Chemical Engineering The University of New South Wales Sydney New South Wales 2052 Australia Australian Centre for Advanced Photovoltaics School of Photovoltaic and Renewable Energy Engineering The University of New South Wales Sydney New South Wales 2052 Australia

In this work, we demonstrated the successful construction of metal-free zero- dimensional/two-dimensional carbon nanodot （CND）-hybridized protonatedg=C3N4 （pCN）（CND/pCN） heterojunction photocatalysts b; means of electrostatic attraction. We experimentally found that CNDs with an average diameter of 4.4 nm were uniformly distributed on the surface of pCN using electron microscopy analysis. The CND/pCN-3 sample with a CND content of 3 wt.% showed thehighest catalytic activity in the CO2 photoreduction process under visible and simulated solar light. This process results in the evolution of CH4 and CO. Thetotal amounts of CH4 and CO generated by the CND/pCN-3 photocatalyst after 10 h of visible-light activity were found to be 29.23 and 58.82 molgcatalyst-1, respectively. These values were 3.6 and 2.28 times higher, respectively, than thearn＊ounts generated when using pCN alone. The corresponding apparent quantum efficiency （AQE） was calculated to be 0.076%. Furthermore, the CND/pCN-3 sample demonstrated high stability and durability after four consecutive photoreaction cycles, with no significant decrease in the catalytic activity.

关键词： protonated graphiticcarbon nitride carbon nanodots photocatalysis carbon dioxide reduction charge carrier dynamics density functional theory（DFT） calculations

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Regeneration of sintered Rh/ZrO2 catalysts via Rh re-dispersion and Rh–ZrO2 interaction

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Science China(Technological Sciences) 2016年第7期59卷 1023-1028页

作者： WAN Jie CAO YiDan RAN Rui LI Min XIAO Yi WU XiaoDong WENG Duan Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and Engineering Tsinghua University Beijing 100084 China Haier Group Technique R&D Center Qingdao 266101 China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China

Rh/ZrO2 catalyst was prepared by the impregnation method and then aged in N2 atmosphere with 10% steam at 1050℃ for 12 h. The regeneration of the aged catalyst was examined by slow cooling the catalyst in O2 following preheating at 950℃. The as-prepared, aged, and regenerated catalysts were characterized by X-ray diffraction, Brunauer–Emmett–Teller specific surface area analysis, and（CO＋NO） reaction activity tests, CO chemisorption, and transmission electron microscopy. The results revealed that the Rh species on ZrO2 that underwent severe sintering during the high-temperature aging process could be regenerated by the slow re-oxidation process employed herein. Owing to the remarkable increase in the degree of Rh dispersion after the regeneration process, the activity could be markedly recovered. Further investigations revealed that such a regeneration phenomenon, involving the re-dispersion of the Rh species during the slow cooling process in O2, was strongly related to the phase transformation of the ZrO2 support and the interaction between the Rh and tetragonal ZrO2 species.

关键词： Rhodium zirconia sintering regeneration re-dispersion Rh–Zr interaction

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