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Aligned Carbon-Doping to Modulate Thermal and Electrical Conductivity of Boron Carbon Nitride Grown from Chemical Vapor Deposition

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SSRN 2023年

作者： Galligan, Patrick Ryan Xu, Yixin Tang, Tsz Wing Liu, Hongwei Tamtaji, Mohsen Zhou, Yanguang Luo, Zhengtang Department of Chemical and Biological Engineering William Mong Institute of Nano Science and Technology The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong Hong Kong Quantum AI Lab Limited Pak Shek Kok Hong Kong HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute Futian Guangdong Shenzhen China Hong Kong University of Science and Technology Shenzhen Research Institute No. 9 Yuexing first RD Hi-Tech Park Nanshan Shenzhen518057 China

Hexagonal boron carbon nitride (hBCN) thin films with a wide range of carbon doping are synthesized in a chemical vapor deposition (CVD) process by varying 3 distinct precursors. Utilizing the optothermal method, the highest thermal conductivities of hBCN thin films is measured experimentally as 460±149 W/m·K, for the hBCN with the highest carbon doping, surpassing the measured hBN conductivity of 313±86 W/m·K. Moreover, we demonstrate that the electrical conductivity retains the insulative properties of hBN with lower carbon doping levels. Additionally, insights of how increasing amounts of carbon increase the conductivity by forming graphene like channels integrated into the hBN networks have been examined by molecular dynamics simulations. These simulations confirm a greater increase in high frequency phonon group velocities contribute to higher thermal conductivity, when aligning carbon rather than simply increasing the quantity of carbon. The aligned carbon channels are effective in overcoming the additional phonon scattering, that occurs especially in the LA mode, when adding carbon to the hBN network. By varying the carbon doping to maximize the thermal conductivity while minimizing the electrical conductivity, we have discovered an effective method of producing optimized hBCN thin films, which are ideal to be utilized in thermal interface material applications as a lower cost alternative to hBN. © 2023, The Authors. All rights reserved.

关键词： Chemical vapor deposition

Efficient photocatalytic degradation of ciprofloxacin using floating α-NiMoO4/mpg-C3N4/EP under visible light

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Chemosphere 2024年 366卷 143413页

作者： Truong, Hai Bang Dao, Duy Quang Do, Ha Huu Van Tran, Vinh Nguyen, Chi Van Rabani, Iqra Hur, Jin Optical Materials Research Group Science and Technology Advanced Institute Van Lang University Ho Chi Minh City Viet Nam Faculty of Applied Technology School of Technology Van Lang University Ho Chi Minh City Viet Nam Institute of Research and Development Duy Tan University Da Nang550000 Viet Nam School of Engineering and Technology Duy Tan University Da Nang550000 Viet Nam NTT Hi-Tech Institute Nguyen Tat Thanh University Ho Chi Minh City700000 Viet Nam Department of Mechanical Engineering Gachon University Seongnam13120 Korea Republic of Center for Innovative Materials and Architectures Ho Chi Minh City Viet Nam Vietnam National University Ho Chi Minh City Viet Nam Department of Nanotechnology and Advanced Materials Engineering Sejong University Seoul05006 Korea Republic of Department of Environment and Energy Sejong University Seoul05006 Korea Republic of

Conventional water treatment processes often fail to effectively remove antibacterial drugs, necessitating advanced strategies. This study presents the synthesis of novel floating, visible light-active α-NiMoO4/mpg-C3N4/EP composites for the removal of ciprofloxacin (CFX), a widely used quinolone antibiotic, from water. These composites are easily recoverable, highly stable, and demonstrate excellent reusability. The optimal photocatalyst, NC-101/EP (α-NiMoO4/mpg-C3N4 = 10:1), achieved 96.2 ± 1.1% degradation of CFX at 1.6 g L−1 within 80 min under visible light, significantly outperforming previous benchmarks. This high efficiency is attributed to the formation of interfacial junctions and a built-in electric field, which enhanced charge transfer and hydroxyl radical generation through an S-scheme mechanism. Fluorescence spectroscopy provided precise monitoring of CFX degradation without interference from coexisting intermediates. Density functional theory (DFT) calculations revealed that hydroxyl radicals initiated highly favorable and spontaneous oxidation of CFX, with a reaction rate constant of 6.04 × 109 M−1 s−1. The preferred oxidation pathway followed the sequence: HO-addition > H-abstraction > single electron transfer. Four degradation pathways were identified, with key intermediates confirmed by high-resolution mass spectrometry. The process also significantly reduced CFX toxicity, ensuring minimal environmental impact. These findings position NC-101/EP as a promising photocatalyst for large-scale water treatment applications targeting antibiotic contamination. © 2024 Elsevier Ltd

关键词： Rate constants

Solution Blending Preparation of Polyurethane/Graphene Composite: Improving the Mechanical and Anti-Corrosive Properties of the Coating on Aluminum Surface

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SSRN 2023年

作者： Pham, Gia Vu Pham, Duc Linh Nguyen, The Duy Do, Ha Huu Hui, Kwun Nam Pham, Gia Khanh Dinh, Duc Anh Institute for Tropical Technology Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Cau Giay Hanoi10000 Viet Nam NTT Hi-Tech Institute Nguyen Tat Thanh University Ho Chi Minh City700000 Viet Nam Faculty of Materials Science and Technology University of Science – VNUHCM Ho Chi Minh City700000 Viet Nam Institute of Applied Physics and Materials Engineering University of Macau 999078 China Munich University of Applied Sciences Lothstr. 34 Munich80335 Germany

Graphene-based polyurethane composites (PU/G) are prepared by using a simple and scalable solution blending method to disperse graphene flakes into the polyurethane matrix. The PU/G composite with 1wt% of graphene flakes performs the significant improvement (~50%) of the impact strength and adhesion behavior with respect to that of pristine PU. The PU/G coating with 2 wt% of graphene achieves the highest long-term anti-corrosion performance with the stable impedance modulus of ~2.7x1010 Ω.cm2 after 150 immersed days and 2500 hours of salt spray exposure in 3 wt% NaCl solution. © 2023, The Authors. All rights reserved.

关键词： Graphene

Research and Development Progress of Domestic Polypropylene Capacitor Film

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Gaodianya Jishu/high Voltage engineering 2025年第5期51卷 2234-2245页

作者： Wang, Ke Liu, Gang Meng, Sen Xie, Zilong Yao, Lulu Wei, Qi College of Polymer Science and Engineering Sichuan University Chengdu610065 China Electric Power Research Institute CSG Guangzhou510663 China National Engineering Research Center of UHV Technology and Novel Electrical Equipment Basis Kunming651705 China FSPG Hi-Tech Co. Ltd. Foshan528000 China

Polypropylene film capacitors are widely used in power transmission and transformation engineering, civil home appliances and new energy equipment. With the development of ultra-high voltage smart grid and other emerging industries, the demands for high-performance film capacitors are increasing. However, at present, the ultra-clean polypropylene raw materials involved in polypropylene film capacitors are completely dependent on import from abroad. Although domestic substitute polypropylene resin raw materials have been developed in China, the processing stability and comprehensive performance are poor when making capacitor films. Once the raw material is out of supply in foreign countries, the polypropylene film capacitor will become a jammed problem. It is urgent to develop the capacitor film production technology suitable for domestic materials and form an independent supporting process. In this paper, along with the process of film-forming technology of domestic capacitive films, the problems found and the progress achieved in the process of experimental verification of the in-depth cooperation between manufacturers and scientific research institutes in related fields are discussed. Firstly, the development status of polypropylene capacitor film is summarized, especially the development progress of domestic capacitor film and its comparison with imported capacitor film. At present, by optimizing the tensile process, chain structure regulation and crystal structure regulation, the domestic crude film reaches or exceeds the level of similar imports in terms of porosity, roughness and dielectric strength, while the metallized film shows better performance in terms of loss and breakdown field strength. The influence of the stretching temperature on the oriented crystal structure of the capacitor film and the relationship between the structural evolution of the film and the electrical properties under different stretching methods (synchronous and asynchronous) are al

关键词： Stretching

A Simple Approach to Achieve Organic Radicals with Unusual Solid-State Emission and Persistent Stability

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CCS Chemistry 2022年第6期4卷 1912-1920页

作者： Xueqian Zhao Junyi Gong Parvej Alam Chao Ma Yanpei Wang Jing Guo Zebin Zeng Zikai He Herman H.Y.Sung Ian D.Williams Kam Sing Wong Sijie Chen Jacky W.Y.Lam Zheng Zhao Ben Zhong Tang Department of Chemistry Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and ReconstructionInstitute for Advanced Study and Guangdong-Hong Kong-Macro Joint Laboratory of Optoelectronic and Magnetic Functional MaterialsHong Kong University of Science and TechnologyClear Water BayKowloonHong Kong 999077 Department of Physics Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong 999077 State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangshaHunan Province 410082 School of Science Harbin Institute of TechnologyShenzhenHIT Campus of University TownShenzhenGuangdong Province 518055 Ming Wai Lau Centre for Reparative Medicine Karolinska InstitutetHong Kong 999077 School of Science and Engineering Chinese University of Hong KongShenzhenGuangdong Province 518172 HKUST-Shenzhen Research Institute South Area Hi-Tech ParkNanshanShenzhenGuangdong Province 518057 Center for Aggregation-Induced Emission SCUTHKUST Joint Research InstituteState Key Laboratory of Luminescent Materials and DevicesSouth China University of TechnologyGuangzhouGuangdong Province 510640 AIE Institute Guangzhou Development DistrictHuangpuGuangzhouGuangdong Province 510530

Sable organic radicals are promising materials for information storage,molecular magnetism,electronic devices,and biological *** organic radicals have been prepared,but most are non-or weakly emissive and degrade easily upon *** remains challenging to produce stable and efficient luminescent radicals because of the absence of general guidelines for their ***,we present a photoactivation approach to generate a stable luminescent radical from tris(4-chlorophenyl)phosph ine(TCPP)with red emission in the crystal *** mechanistic study suggests that the molecular symmetry breaking in the crystal causes changes of molecular conformation,redox properties,andmolecular packing that facilitates radical generation and *** design strategy demonstrates a straightforward approach to develop stable organic luminescent radicals that will open new doors to photoinduced luminescent radical materials.

关键词： luminescent radicals symmetry breaking tris(4-chlorophenyl)phosphine anticounterfeiting photoinduced electron transfer

Analyzing Characteristic and Modeling of high-Temperature Proton Exchange Membrane Fuel Cells with Co Poisoning Effect

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SSRN 2023年

作者： Lei, Gang Zheng, Hualin Zhang, Jun Chin, Cheng Siong Xu, Xinhai Zhou, Weijiang Zhang, Caizhi School of Mechatronic Engineering Southwest Petroleum University Chengdu610500 China College of Mechanical and Vehicle Engineering The State Key Laboratory of Mechanical Transmissions Chongqing Automotive Collaborative Innovation Centre Chongqing University Chongqing400044 China School of Mechanical Engineering Zhejiang University Hangzhou310027 China Faculty of Science Agriculture and Engineering Newcastle University in Singapore 599493 Singapore School of Mechanical Engineering and Automation Harbin Institute of Technology Guangdong Shenzhen China Sinocat Environmental Technology Co Ltd Chengdu Hi-tech Industrial Development Zone Chengdu611731 China

high-temperature proton exchange membrane fuel cells (HT-PEMFC) have strong resistance to CO poisoning. However, the published CO poisoning models for HT-PEMFC are based on the finite element analysis method, which are difficult to use for the performance prediction and development of system control strategy due to a large amount of calculation. In the beginning, a semi-empirical model of HT-PEMFC is deduced based on the analysis of the CO poisoning characteristics. Then the key parameters of ohmic impedance and concentration polarization advance correction factor are obtained by fitting the polarization curves, dissociation and adsorption activation energy of H2 and CO are obtained by the calculation, respectively. The slope of the straight line segment in the ohmic polarization interval of the polarization curve is linearly related to ln[H2/CO]. The change of limiting current density is the main factor for the advance of concentration polarization. The fitted ohmic impedance varies with temperature and CO concentration, but changes little above 175 oC. CO coverage depends primarily on dissociation and adsorption activation energy of CO. Subsequently, the proposed model is validated with experimental data and shows high similarity. The model can be used for studying the systematic control strategy development and performance monitoring of HT-PEMFC. © 2023, The Authors. All rights reserved.

关键词： Dissociation

Iron Magnetic Nanoparticles Coated with Various Pvp Loadings: Evaluation of Magnetic Properties and Morphology

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SSRN 2023年

作者： Shikh Zahari, S.M. Shahrul Nizan Weber, Cameron C. Puspitasari, Poppy Che Sam, Nur Fatin Izzati Muhamad Tajuddin, Nurul Hafizah Mohd Zainon, Nurazilah Elzaneen, Kholoud M.H. Industrial Chemical Technology Programme Faculty of Science and Technology Universiti Sains Islam Malaysia Bandar Baru Nilai Negeri Sembilan Nilai71800 Malaysia Department of Chemical Engineering South Kensington Campus Imperial College London LondonSWZ 2AZ United Kingdom Mechanical Engineering Department Engineering Faculty Malang State University Semarang Street 5 Malang East Java Indonesia School of Chemical Sciences University of Auckland Auckland1010 New Zealand MacDiarmid Institute of Advanced Materials and Nanotechnology Wellington6140 New Zealand Industrial Centre of Innovation in Biomedical SIRIM Industrial Research Lot 34 Jalan Hi-Tech 2/3 Kulim Hi-Tech Park Kulim Kedah 09000 Malaysia

Polyvinylpyrrolidone iron magnetic nanoparticles (PVP-Fe MNPs) have proven to be useful materials for the separation of oil-water mixtures. However, the relationship between the PVP loading and properties of these materials is not currently well understood. In this study, we examine the changes in the magnetic properties and morphology of PVP-Fe MNPs as a result of varying the PVP loading. The samples were synthesised by a co-precipitation technique in a homogeneous solution containing PVP and iron salts. Analysis revealed that the PVP loading had an inverse relationship with the magnetic properties (M s , M r and H c ), which was mainly impacted by the morphology of the resultant PVP-Fe MNPs. Thermogravimetric and CNS analyses were used to characterise the proportion of PVP bound to these materials. These results suggest that the properties of these PVP-Fe MNPs can be tuned by the PVP loading used in their synthesis, allowing these materials to be tailored for the targeted application. © 2023, The Authors. All rights reserved.

关键词： Magnetic properties

Regulating the Aspect Ratio of Bulk Graphene to Improve the Field Emission Performance

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SSRN 2023年

作者： Zhang, Yihui Ding, He Liu, Chenxu Zhang, Jiacheng Wang, Chengbao Guo, Wenhua Ji, Qianyu Zhao, Jiyuan Zi, Yanyang School of Mechanical Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China School of Materials Science and Engineering Zhengzhou University of Aeronautics Zhengzhou450046 China School of Future Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China National Innovation Institute of Additive Manufacturing #997 Shanglinyuan 8th Road Hi-tech District Shaanxi Xi’an710000 China School of Automation Beijing Information Science and Technology University Beijing100192 China

Graphene is a promising material for field emission owing to its excellent electrical conductivity and local electric field enhancement capability from abundant electron tunneling edges. However, graphene thin-film emitters mostly emitted in planar structures. And due to the flexibility of the thin film, it is difficult to achieve vertical structure emission with large aspect ratio. Therefore, the emission performance of current graphene field emitters is difficult to meet the requirements of high current applications. In this study, bulk graphene cathodes were formed by cold pressing to achieve upright structural field emission, and the emission performance was enhanced by regulating the aspect ratio. The obtained bulk graphene emitters have a higher conductivity of 2498 S/cm and tensile strength of 4.64 MPa. The turn-on electric field (at 50 mA/cm2) and threshold electric field (at 100 mA/cm2) values were determined to be 2.14 V/μm and 3.24 V/μm, respectively, with a maximum current density of 1167 mA/cm2 (at 6.74 V/μm) and a maximum field enhancement factor 14499. Excellent emission stability was observed over a continuous period of 110h at a 5mA @ 526 mA/cm2. With the increase of emission current, the bulk graphene with large aspect ratio has better emission stability. This work provides insights into the appication of graphene-based field emitters at large current. © 2023, The Authors. All rights reserved.

关键词： Graphene

An anti-freezing biomineral hydrogel of high strain sensitivity for artificial skin applications

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Nano Research 2022年第7期15卷 6655-6661页

作者： Junda Shen Peng Du Binbin Zhou Guobin Zhang Xinxue Tang Jie Pan Bo Li Jingyang Zhang Jian Lu Yang Yang Li Hong Kong Branch of National Precious Metals Material Engineering Research Centre(NPMM) City University of Hong KongKowloonHong Kong 999077China Department of Material Science and Engineering City University of Hong KongKowloonHong Kong 999077China Center of Super-Diamond and Advanced Films(COSDAF) City University of Hong KongKowloonHong Kong 999077China Shenzhen Geim Graphene Center Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Center for Advanced Structural Materials City University of Hong Kong Shenzhen Research InstituteGreater Bay Joint DivisionShenyang National Laboratory for Materials Science8 Yuexing 1st RoadShenzhen Hi-Tech Industrial ParkNanshan DistrictShenzhen 518000China CityU-Shenzhen Futian Research Institute 3rd Binlang RoadShenzhen-Hong Kong International Science and Technology ParkFutian DistrictShenzhen 518000China

Mineral hydrogels have caught a lot of attention for their strong competency as artificial skin-like ***,it remains a great difficulty in fulfilling in one hydrogel system a range of key functionalities that are needed for practical artificial skin applications,i.e.,to be biocompatible,strain-sensitive,ion-conductive,elastic and robust,anti-swelling,and *** we present a such type of versatile hydrogel that is not only capable to deliver all the above-mentioned key functionalities but also highly *** novel hydrogel is constructed by introducing a gelatinous and amorphous multi-ionic biomineral(denoted as Mg-ACCP,containing Mg^(2+),Ca^(2+),CO_(3)^(2−),and PO_(4)^(3−))into the network of biocompatible polyvinyl alcohol(PVA)and sodium alginate(SA).The presence of Mg^(2+)and PO_(4)^(3−)in this hydrogel helps prohibit the crystallization of the biominerals,leading to significantly improved *** hydrogel thus obtained delivers excellent mechanical performance due to the chelation between the mineral ions and the organic matrix,and high sensitivity even to subtle pressure and strain applied,such as slight finger bending and gentle ***,the novel hydrogel features high ionic conductivity,high resistance to swelling,and extraordinary anti-freezing property,holding great promise for applications in different practical scenarios,particularly in aqueous or cold environments.

关键词： mineral hydrogel artificial skin biominerals mechanical performance