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Multilayer nanocomposite films with enhanced piezoelectric properties doping PZT nanofibers

cERAMIcS INTERNATIONAL 2023年第17期49卷 28474-28483页

作者： Yuan, chongXiao Zhang, chao Xiao, Shibing Yang, cheng Zhang, Nannan Sun, Huajun Wuhan Univ Technol State Key Lab Silicate Mat Architectures Wuhan 430070 Peoples R China Wuhan Univ Technol Sch Mat Sci & Engn Wuhan 430070 Peoples R China Wuhan Univ Technol Sch Chem Chem Engn & Life Sci Wuhan 430070 Peoples R China Adv Ceram Inst Zibo New & High Tech Ind Dev Zone Zibo 255000 Peoples R China

Flexible electronics components, including wearable sensors, miniature energy supply devices, and energy harvesting systems based on polymer piezoelectric materials, have garnered extensive attention. This study focuses on the preparation of PZT nanofibers (PZT NFs) via electrospinning and their modification with polydopamine, the fabrication of PVDF/PZT NFs nanocomposite films through casting, and the production of tri-layer nanocomposite films using hot pressing. The alignment of the PZT NFs perpendicular to the electric field direction enhances the breakdown strength (Eb) and facilitates the polarization of the nanocomposite films. At the interlayer interfaces within the tri-layer structure, electron traps extend the breakdown path, attenuating charge concentration and mitigating the electric field concentration effect. consequently, the tri-layer films exhibit excellent electrical properties. Notably, the P4P tri-layer nanocomposite films have a high Eb of 290.47 kV/mm and a piezoelectric coefficient of -24 pc/N. This paper presents a promising strategy for enhancing the piezoelectric properties of polymer piezoelectric materials applied in sensors and energy harvesting systems.

关键词： A Tape casting B composites c Piezoelectric properties D PZT

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Methanol electro-oxidation on carbon-supported Pt and Au@Pt nanoparticles with quasi-spherical and polyhedral forms in acid aqueous medium

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JOURNAL OF SOLID STATE ELEcTROcHEMISTRY 2023年第11期27卷 2927-2936页

作者： Roque-de-la-O, N. Vazquez-Huerta, G. corona-Avendano, S. Arce-Estrada, E. M. Refugio-Garcia, M. E. Palomar-Pardave, M. Metropolitan Autonomous Univ Azc Dept Mat Mexico City Mexico Natl Polytech Inst ESIQIE Dept Met Engn Mexico City Mexico

In this work, monometallic Pt and bimetallic Au@Pt (core-shell) nanoparticles with different shapes are synthesized by adding Ag+ as a shape-modifying agent, polyhedral forms are obtained: Pt-0.02 (cubic form), bimetallic Au@Pt-0.1 (angulated polyhedral form), and Au@Pt-0.2 (polyhedral and cube forms). The nanoparticle's shape depends on the amount of Ag+ used during synthesis (subindex indicates the Ag/Pt ratio in all cases). Without Ag+, quasi-spherical Pt and Au@Pt nanoparticles are obtained. The polyhedral and angulated shapes of Pt-0.02/c and Au@Pt-0.1/c are more active for methanol oxidation (0.5 M methanol + 0.5 M H2SO4), in comparison with the quasi-spherical Pt/c, Au@Pt/c and polyhedral/cubic Au@Pt-0.2/c nanoparticles. From these results, it is found that the electrochemical response of the tested catalysts varies not only due to the nature of the electrocatalyst (Pt/c or Au@Pt/c) but on the nanoparticle's shape which is also associated with the dominant crystal plane on their surfaces.

关键词： Methanol oxidation Pt c Au@Pt Shaped nanoparticles

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Extraction and characterization of pectin from fruit peels of Irvingia gabonensis and pulp of cola milleni and Theobroma cacao as precursor for industrial applications

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BIOMASS cONVERSION AND BIOREFINERY 2023年第3期13卷 2125-2133页

作者： Oloye, Mariam T. Jabar, Jamiu M. Adetuyi, Abayomi O. Lajide, Labunmi Univ Med Sci Dept Chem Ondo City Ondo State Nigeria Fed Univ Technol Akure Dept Chem Akure Ondo State Nigeria

Pectin is a complex polysaccharide that makes up about one third of the cell wall of higher plants. It was extracted from fruit peels of Irvingia gabonensis and pulp of cola milleni and Theobroma cacao using acid extraction and alcohol precipitation methods. The effects of temperature and time on the yield and physicochemical properties of the extracted pectin were evaluated. Optimum yields of pectin from c. milleni, I. gabonensis, and T. cacao were 10.73%, 19.83%, and 11.73% respectively at extracting period of 150 min and temperature of 100 degrees c. Although there was significant difference in moisture content, degree of esterification, equivalent weight, and methoxyl content of the extracted pectins, there was no significant difference in yield, protein, and ash content at 95% confidence interval. The monosaccharide composition of the three pectins shows that the extracted pectin composed of galacturonic acid and minor neutral sugars. Major functional groups in the extracted pectin show peaks in the region between 1000 and 2000 cm(-1). The bands observed between 1627-1651 cm(-1) and 1739-1793 cm(-1) indicated the presence of the carbonyl group stretching. The surface morphologies of the extracted pectins show irregular shapes, non-smooth surfaces, and unequal sizes which also reveals more silica nodes in cocoa pulp pectin than in other pectins. Thermogravimetric analysis of the pectin samples shows multi-step stages of thermal decomposition, indicating wide range of thermal stability. The overall results specified that the pectins extracted from these plants are suitable for industrial applications.

关键词： c milleni I gabonensis T cacao Methoxyl content Anhydrouronic acid

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Biogas production from anaerobic co-digestion using kitchen waste and poultry manure as substrate-part 1: substrate ratio and effect of temperature

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BIOMASS cONVERSION AND BIOREFINERY 2023年第8期13卷 6635-6645页

作者： Rahman, Md Anisur Shahazi, Razu Nova, Syada Noureen Basher Uddin, M. Rakib Hossain, Md Shahadat Yousuf, Abu Shahjalal Univ Sci & Technol Dept Chem Engn & Polymer Sci Sylhet 3114 Bangladesh Univ Napoli Parthenope Dept Engn I-80143 Naples Italy

The rapidly declining fossil fuels are no longer able to meet the ever-increasing energy demand. Moreover, they are considered responsible for greenhouse gas (GHG) emission, contributing to the global warming. On the other hand, organic wastes, such as kitchen waste (KW) and poultry manure (PM), represent considerable pollution threat to the environment, if not properly managed. Therefore, anaerobic co-digestion of KW and PM could be a sustainable way of producing clean and renewable energy in the form of biogas while minimizing environmental impact. In this study, the anaerobic co-digestion of KW with PM was studied to assess the rate of cumulative biogas (cBG) production and methane percentage in four digester setups (D1, D2, D3, and D4) operated in batch mode. Each digester setup consisted of five parallelly connected laboratory-scale digesters having a capacity of 1 L each. The digester setups were fed with KW and PM at ratios of 1:0 (D1), 1:1 (D2), 2:1 (D3), and 3:1 (D4) at a constant loading rate of 300 mg/L with 50 gm cow manure (cM) as inoculum and were studied at both room temperature (28 degrees c) and mesophilic temperature (37 degrees c) over 24 days. The co-digestion of KW with PM demonstrated a synergistic effect which was evidenced by a 16% and 74% increase in cBG production and methane content, respectively, in D2 over D1. The D3 with 66.7% KW and 33.3% PM produced the highest cBG and methane percentage (396 +/- 8 mL and 36%) at room temperature. At mesophilic condition, all the digesters showed better performance, and the highest cBG (920 +/- 11 mL) and methane content (48%) were observed in D3. The study suggests that co-digestion of KW and PM at mesophilic condition might be a promising way to increase the production of biogas with better methane composition by ensuring nutrient balance, buffering capacity, and stability of the digester.

关键词： co-digestion Kitchen waste Poultry manure Biogas Degradation rate c N Mesophilic temperature

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Augmenting the discovery of computationally complex ceramics for extreme environments with machine learning

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JOURNAL OF MATERIALS RESEARcH 2023年第23期38卷 5055-5064页

作者： Bavdekar, Salil Hennig, Richard G. Subhash, Ghatu Univ Florida Dept Mat Sci & Engn Gainesville FL 32611 USA Univ Florida Quantum Theory Project Gainesville FL 32611 USA Univ Florida Dept Mech & Aerosp Engn Gainesville FL 32611 USA

We present a high-throughput, material-agnostic strategy to discover new compositionally complex ceramics (c3) for extreme environments by utilizing machine learning (ML) techniques to predict the stoichiometries and properties of structures within a given design space. This example study focuses on a well-understood design space (Si-c-N) so that predictions may be validated. Evolutionary structure searches coupled with density functional theory (DFT) calculations are applied to find structures with low energies (i.e., lying on or close to the convex hull), while also maximizing a targeted property (in this case, hardness). The structure-property relationship data obtained throughout these searches are exploited in ML algorithms to create an accurate and efficient surrogate model of the energy and hardness landscapes. The ML models serve to screen structures with optimal attributes and reduce computational costs associated with the property calculations, thereby accelerating the discovery of new structures and stoichiometries with desired traits.

关键词： Machine learning crystallographic structure Hardness Si c N

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Achieving Good Bonding Strength of the cu Layer on PET Films by Pretreatment of a Mixed Plasma of carbon and copper

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AcS APPLIED MATERIALS & INTERFAcES 2023年第9期15卷 12590-12602页

作者： Li, Yue Wang, Yongxin Wang, Ying Wu, Yutao Chinese Acad Sci Ningbo Inst Mat Technol & Engn Key Lab Marine New Mat & Related Technol Zhejiang Key Lab Marine Mat & Protect Technol Ningbo 315201 Peoples R China Changzhou Univ Jiangsu Collaborat Innovat Ctr Photovolt Sci & Eng Sch Mat Sci & Engn Jiangsu Prov Cultivat Base State Key Lab Photovolt Changzhou 213164 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

cu layers were fabricated on PET films with and without pretreatment by a mixed plasma composed of carbon and copper using a magnetron sputtering technique for potential application as the flexible copper-clad laminate (FccL) in 5G technology. In order to evaluate the effect of carbon plasma on the composited layer, the graphite target current was adjusted from 0.5 to 2.0 A. The microstructures and properties of cu layers on PET films with different treatments were measured by an X-ray powder diffractometer, X-ray photoelectron spectroscope, Raman spectro-scope, scanning electron microscope, transmission electron micro-scope, scratching test, indentation test, and four-probe detector. The results showed that the organic polymer carbon structure on the surface of PET films was changed to inorganic amorphous carbon due to the effect of the carbon plasma. At the same time, the active free radicals formed in the transition process react with metal copper ions to form organometallic compounds. Under the treatment of a mixed plasma of carbon and copper, the c/cu mixed layer was formed on the PET film at the top of the substrate. Due to the presence of c/cu mixed interlayers, the bonding strengths between the final cu layers and the PET film substrates were improved, and the strongest bonding strength appeared when the graphite target current was 1.0 A. In addition, the presence of the c/cu mixed interlayer enhanced the toughness of the cu layer on PET film. It was proposed that the good bonding strength in combination and the enhanced toughness for the cu layer on a PET film was due to the formation of a c/cu mixed interlayer induced by the pretreatment of a mixed plasma of carbon and copper.

关键词： copper-clad plate PET film pretreatment c cu layer bonding strength flexibility

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?Electrons-siphoning? of sulfate reducing bacteria biofilm induced sharp depletion of Al--Zn--In--Mg--Si sacrificial anode in the galvanic corrosion coupled with carbon steel

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cORROSION ScIENcE 2023年第1期216卷

作者： Zhang, Tiansui Wang, Zhengyun Qiu, Yubing Iftikhar, Tayyaba Liu, Hongfang Huazhong Univ Sci & Technol Hubei Engn Res Ctr Biomat & Med Protect Mat Hubei Key Lab Mat Chem & Serv Failure Sch Chem & Chem EngnKey Lab Mat Chem Energy Conve Wuhan 430074 Peoples R China

The microbiologically influenced corrosion (MIc) of Al--Zn--In--Mg--Si sacrificial anode coupled with X80 carbon steel induced by sulfate reducing bacteria (SRB) was investigated. Results revealed that SRB strongly promoted the galvanic current density between the aluminum anode and carbon steel by facilitating the cathodic process of the galvanic corrosion on carbon steel. In the medium with SRB, 73.7% of the corrosion loss of aluminum anode coupled to carbon steel was caused by the enhanced galvanic corrosion. SRB biofilm on the carbon steel continuously obtained electrons from the aluminum anode, which was like an "electrons-siphoning" process in the galvanic corrosion.

关键词： A Sacrificial anode carbon steel B Hilbert -Huang transform c Galvanic corrosion Microbiological corrosion

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Effect of green body annealing on microstructure and optical properties of Y2O3:Yb3+ceramics

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cERAMIcS INTERNATIONAL 2023年第17期49卷 29048-29054页

作者： Parkhomenko, Serhii Balabanov, Anton Kryzhanovska, Oleksandra Safronova, Nadiia Vorona, Ihor Doroshenko, Andrii Vovk, Olena Vashchenko, Olga Tolmachev, Alexander Yavetskiy, Roman NAS Ukraine Inst Single Crystals 60 Nauky Ave UA-61072 Kharkiv Ukraine NAS Ukraine Inst Scintillat Mat UA-61072 Kharkiv Ukraine

Influence of annealing temperature in the T = 600-1200 degrees c range on a mesostructure of Y2O3:Yb3+ green bodies and properties of obtained ceramics were studied. It was shown that annealing of green bodies should be carried out at the maximum possible temperatures when sintering occurs without approaching of particle centers. It was established that green bodies annealed at T = 800 degrees c are characterized by optimal mesostructure in terms of densification efficiency during subsequent vacuum sintering. Y2O3:Yb3+ ceramics prepared from green bodies which were previously annealed at 800 degrees c possess the highest optical quality and in-line optical transmittance of 72% at & lambda;= 1100 nm wavelength. Annealing at lower temperatures does not remove all the defects introduced by ball-milling of powder mixture, that hinders formation of pore-free ceramics. Green bodies annealing above T = 800 degrees c leads to partial compact densification that is accompanied with a decrease in sinterability during vacuum sintering.

关键词： A Sintering B Microstructure-prefiring Porosity c Optical properties E Functional applications

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Properties and mechanism of mullite whisker toughened ceramics

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cERAMIcS INTERNATIONAL 2023年第7期49卷 10238-10248页

作者： Zhao, Penglong Ma, Shuhua Wang, Xiaohui Wu, Wei Ou, Yanjun Beijing Univ Chem Technol Coll Chem Engn Beijing 100029 Peoples R China Chinese Acad Sci Inst Proc Engn CAS Key Lab Green Proc & Engn Beijing 100190 Peoples R China Chinese Acad Sci Innovat Acad Green Manufacture Beijing 100190 Peoples R China Chinese Acad Sci Natl Engn Res Ctr Green Recycling Strateg Met Reso Inst Proc Engn Beijing 100190 Peoples R China

High-strength ceramics were prepared from high alumina fly ash (HAFA) and activated alumina as raw materials with magnesia as a sintering additive. The growth kinetics and influence mechanism of secondary mullite whiskers were investigated. Meanwhile, the effects of the Al2O3/SiO2 mass ratio (A/S) and the amount of magnesia on the content and morphology of mullite in the green body were investigated, so as to emphasize the effect of the liquid phase in the sintering process on the growth of secondary mullite whiskers. The results showed that the aspect ratio of secondary mullite whiskers increased significantly after adding activated alumina to increase the A/S ratio of raw materials. When 30 wt% activated alumina was added, the mullite content increased by 5.39%, and the whisker length increased from 1.36 mu m to 4.18 mu m. The addition of magnesia improved the liquid phase formed during the sintering process and the K value method was used to determine the sintering liquid phase content under various conditions. It was observed that increasing the magnesia level by 1 wt% could raise the liquid phase content by 5-7%. When the total liquid content of the system was 30-40%, the growth activation energy in the diameter direction of the whisker reduced significantly, promoting the growth of secondary mullite whiskers along the c axis. The morphology of mullite gradually developed from fibrous to long columnar crystal, making it combine more densely with the green body matrix. Furthermore, the staggered long columnar mullite crystal structure changes the fracture mode of ceramics from intergranular to transgranular fracture, which fully uses the high mechanical strength of mullite. As a result, the fracture energy and strength of ceramics are significantly improved.

关键词： A Grain growth c Fracture D Mullite Liquid phase sintering MgO

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Selective formation of crystal polymorphs in Er3+-doped Bi2O3 thin films and their photoluminescence properties

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cERAMIcS INTERNATIONAL 2023年第6期49卷 9069-9089页

作者： Akazawa, Housei NTT Corp NTT Device Innovat Ctr 3-1 Morinosato Wakamiya Atsugi Kanagawa 2430198 Japan

The process conditions for selectively forming crystal polymorphs in Er3+-doped Bi2O3 films deposited on Si, SiO2, and c-plane sapphire substrates were systematically investigated. Bi2O3:Er films were deposited at either room temperature or 300 degrees c and subsequently post annealed to promote crystallization. The critical factor controlling the crystal polymorphs was Er content. When the Er content was less than 1.5 at.%, only alpha-Bi2O3 phase nucleated upon post annealing. Deposition at 300 degrees c somewhat lowered the oxidization state, under which beta-Bi2O3 structure appeared at lower temperatures and alpha-Bi2O3 structure appeared at higher temperatures. When the films were doped with over 2 at.% Er3+ ions, the excess Er2O3 stabilized the delta-Bi2O3 structure as the lowest temperature phase. The universal phase transition scheme with increasing annealing temperature was delta-Bi2O3 -> beta-Bi2O3 -> alpha-Bi2O3. The delta -> beta transition proceeded through splitting each diffraction peak of delta-Bi2O3 into two components of beta-Bi2O3, indicating a correlation between the structures of beta-Bi2O3 and delta-Bi2O3. The gamma-Bi2O3 phase appeared only in films on Si(100) substrates and after vacuum annealing, suggesting the formation of sillenite (Bi12SiO20). Deposition on c-plane sapphire by using H2O as the oxygen source gas produced a highly (111) -oriented delta-Bi2O3 structure, whereas deposition with O2 yielded a randomly oriented delta-Bi2O3 structure. At Er content exceeding 4 at.%, delta-Bi2O3 was the primary phase in the films on SiO2. The photoluminescence (PL) activity of dopant Er3+ under excitation at a wavelength of 532 nm strongly depended on the crystal polymorphs. alpha-Bi2O3:Er exhibited intense and stable PL spectra consisting of eight Stark splitting lines. PL from gamma-Bi2O3:Er exhibited much weaker two emission lines. delta-Bi2O3:Er and beta-Bi2O3:Er films were not emission-active at all. However, delta-Bi2O3:Er film on SiO2 with a

关键词： A Films B Spectroscopy c Optical properties E Functional applications

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