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Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

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Journal of Energy Chemistry 2024年第1期88卷 1-9,I0001页

作者： Inhyeok Cho Jiwon Yun Boseok Seong Junseok Kim Sun Hee Choi Ho-Il Ji Sihyuk Choi Department of Mechanical Engineering Kumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Department of Aeronautics Mechanical and Electronic Convergence EngineeringKumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Center for Energy Materials research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Center for Hydrogen and Fuel Cell research Clean Technology Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Department of Energy and Environmental Engineering University of Science and TechnologySeoul 02792Republic of Korea Nanomaterials Science and Engineering Korea University of Science and Technology(UST)KIST CampusSeoul 02792Republic of Korea

PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

关键词： Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy

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An effective strategy of constructing multi-metallic oxides of ZnO/ CoNiO_(2)/CoO/C microflowers for improved supercapacitive performance

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Chinese Journal of Chemical Engineering 2024年第3期67卷 1-8页

作者： Wei Guo Yan Zhang Xiaxin Lei Shuang Wang College of Physics Taiyuan University of TechnologyJinzhong 030600China College of Environmental Science and Engineering Taiyuan University of TechnologyJinzhong 030600China Shanxi Key Laboratory of Gas Energy Efficient and clean Utilization Taiyuan University of TechnologyTaiyuan 030024China

In this work,a new ZnO/CoNiO_(2)/CoO/C metal oxides composite is prepared by cost-effective hydrothermal method coupled with annealing process under N_(2) ***,the oxidation-defect annealing environment is conducive to both morphology and component of the composite,which flower-like ZnO/CoNiO_(2)/CoO/C is *** from good chemical stability of ZnO,high energy capacity of CoNiO_(2) and CoO and good conductivity of C,the as-prepared sample shows promising electrochemical behavior,including the specific capacity of 1435 C·g^(-1) at 1 A·g^(-1),capacity retention of 87.3%at 20 A·g^(-1),and cycling stability of 90.5%for 3000 cycles at 5 A·g^(-1),***,the prepared ZnO/CoNiO_(2)/CoO/C/NF//AC aqueous hybrid supercapacitors device delivers the best specific energy of 55.9 W·h·kg^(-1) at 850 W·kg^(-1).The results reflect that the as-prepared ZnO/CoNiO_(2)/CoO/C microflowers are considered as high performance electrode materials for supercapacitor,and the strategy mentioned in this paper is benefit to prepare mixed metal oxides composite for energy conversion and storage.

关键词： Composites Electrochemistry Hydrothermal Transition metal oxides Structural control Supercapacitors

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Elucidating the enhancement of kaolinite flotation by iron content through density functional theory: A study on sodium oleate adsorption efficiency

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International Journal of Mining Science and technology 2024年第6期34卷 855-866页

作者： Lingyun Liu Chuilei Kong Hongyu Zhao Fangqin Lu Joint National-Local Engineering research Centre for Safe and Precise coal Mining Huainan 232001China Department of Materials Science and Engineering Anhui University of Science and TechnologyHuainan 232001China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

This study delves into the intricate relationship between iron(Fe)content in kaolinite and its impact on the adsorption behavior of sodium *** effects of different iron concentrations on adsorption energy,hydrogen bond kinetics and adsorption efficiency were studied through simulation and experimental *** results show that the presence of iron in the kaolinite structure significantly improves the adsorption capacity of sodium *** samples with high iron content have better adsorption properties,lower adsorption energy levels and shorter and stronger hydrogen bonds than pure *** optimal concentration of oleic acid ions for achieving maximum adsorption efficiency was identified as 1.2 mmol/L across different kaolinite *** this concentration,the adsorption rates and capacities reach their peak,with Fe-enriched kaolinite samples exhibiting notably higher flotation recovery *** optimal concentration represents a balance between sufficient oleic acid ion availability for surface interactions and the prevention of self-aggregation phenomena that could hinder *** study offers promising avenues for optimizing the flotation process in mineral processing applications.

关键词： Iron Influence Sodium Oleate Adsorption Kaolinite Surfaces Molecular Interaction Analysis Flotation Efficiency Optimization

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A High-Linear Radio Frequency Quadrature Modulator with Improved Sideband Suppression and Carrier Leakage Performance

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Tsinghua Science and technology 2024年第3期29卷 635-643页

作者： Yingdan Jiang Zongguang Yu Shutong Wu Li Li Xuelian Liu School of Electronic Science and Engineering Nanjing UniversityNanjing 210093China The 58th research Institute of China Electronic technology group Corporation Wuxi 214072China

The quadrature modulator is a crucial block in transmitters that upconverts baseband signals to theRadio Frequency(RF)band of interest using local oscillator *** this paper,non-ideal factors thatinfluence the performance of the quadrature modulator are considered,and solutions are accordingly taken inthe quadrature modulator design.A high-linear RF quadrature modulator with improved sideband suppressionand carrier leakage performance is presented in this *** quadrature modulator implemented in the0.18-μm SiGe process uses the current bleeding technique to improve the general performance of the doublebalanced active Gilbert *** on-chip prescaler followed by two cascaded limiting amplifiers is designed toprovide accurate quadrature local oscillator *** at quadrature baseband signal input ports areproposed to eliminate DC *** measured sideband suppression achieves a performance of better than−43 dBc and carrier leakage is less than−38 dBm over the output RF frequency range of 30 MHz to 2.15 *** output 1 dB compression point equals 11.4 dBm at 800 MHz.

关键词： Radio Frequency(RF) quadrature modulator sideband suppression carrier leakage linearity

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Electron engineering of nickel phosphide for Ni^(δ+) in electrochemical nitrate reduction to ammonia

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Nano research 2024年第6期17卷 4864-4871页

作者： Jie Hu Hao Huang Miao Yu Shuang Wang Jinping Li College of Environmental Science and Engineering Taiyuan University of TechnologyJinzhong 030600China School of Sustainable Energy Materials and Science Jinhua Advanced Research InstituteJinhua 321000China Shanxi Key Laboratory of Gas Energy Efficient and clean Utilization Taiyuan University of TechnologyTaiyuan 030024China

The electrochemical reduction of nitrate to ammonia(ENRA)provides an efficient approach to remove nitrate pollution and achieve ammonia production ***,inspired by bio-enzyme in denitrifying bacteria,a carbon-coated nickel phosphide(NiPC)nanosheet derived from metal-organic frameworks(MOFs)is proposed as an efficient catalyst for *** electron engineering,controllable Ni^(δ+)in nickel phosphide is achieved by regulating the degree of phosphating,which enhances its activity for the hydrogenation of *** the result,Niδ+becomes one of dominating factors determining the efficiency of the ENRA reaction in nickel *** optimal NiPC catalyst exhibits impressive property toward ENRA:NH_(4)^(+)Faraday efficiency of 96.68%,NH4+selectivity of 99.04%,and nitrate conversion rate of 90.43%under low nitrate concentration(200 mg·L^(−1)).This work opens a new avenue for the design of next-generation catalysts through electron engineering for ENRA.

关键词： electron engineering transition metal phosphide nitrate reduction ammonia production metal-organic frameworks

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Theoretical study on the effective thermal conductivity of silica aerogels based on a cross-aligned and cubic pore model

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Chinese Physics B 2024年第6期33卷 28-36页

作者：郑坤灿李震东曹豫通刘犇胡君磊 School of Energy and Environment Inner Mongolia University of Science and TechnologyBaotou 014010China Inner Mongolia Key Laboratory of Efficient and clean Combustion Baotou 014010China

Aerogel nanoporous materials possess high porosity, high specific surface area, and extremely low density due to their unique nanoscale network structure. Moreover, their effective thermal conductivity is very low, making them a new type of lightweight and highly efficient nanoscale super-insulating material. However, prediction of their effective thermal conductivity is challenging due to their uneven pore size distribution. To investigate the internal heat transfer mechanism of aerogel nanoporous materials, this study constructed a cross-aligned and cubic pore model(CACPM) based on the actual pore arrangement of SiO_(2) aerogel. Based on the established CACPM, the effective thermal conductivity expression for the aerogel was derived by simultaneously considering gas-phase heat conduction, solid-phase heat conduction, and radiative heat transfer. The derived expression was then compared with available experimental data and the Wei structure model. The results indicate that, according to the model established in this study for the derived thermal conductivity formula of silica aerogel, for powdery silica aerogel under the conditions of T = 298 K, a_(2)= 0.85, D_(1)= 90 μm, ρ = 128 kg/m^(3), within the pressure range of 0–10^(5)Pa, the average deviation between the calculated values and experimental values is 10.51%. In the pressure range of 10^(3)–10^(4)Pa, the deviation between calculated values and experimental values is within 4%. Under these conditions, the model has certain reference value in engineering verification. This study also makes a certain contribution to the research of aerogel thermal conductivity heat transfer models and calculation formulae.

关键词： silica aerogel effective thermal conductivity two pore-size structure model porous medium heat transfer

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Experimental investigation on coal pore-fracture variation and fractal characteristics synergistically affected by solvents for improving clean gas extraction

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International Journal of Mining Science and technology 2024年第3期34卷 413-425页

作者： Feilin Han Sheng Xue Chunshan Zheng Zhongwei Chen Guofu Li Bingyou Jiang Key Laboratory of Safe and Effective coal Mining of Ministry of Education Anhui University of Science and TechnologyHuainan 232001China School of Safety Science and Engineering Anhui University of Science and TechnologyHuainan 232001China School of Mechanical and Mining Engineering University of QueenslandQLD 4072Australia State Key Laboratory of coal and coalbed Methane Co-Mining Jincheng 048012China

Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction ***,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully *** testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal *** model between permeability,fractal dimension and porosity were *** indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to *** decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,*** treatments could lead to increasing amount of both mesopores and *** ratio of fractal dimension dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to ***,combined solvent could dissolve coal polar and non-polar small molecules and expand flow *** could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.

关键词： clean gas extraction Chemical solvent Experimental investigation Fractal characteristics Pore fracture

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Flotation separation of scheelite from calcite using luteolin as a novel depressant

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 462-472页

作者： Xiaokang Li Ying Zhang Haiyang He Yu Wu Danyu Wu Zhenhao Guan Faculty of Land and Resources Engineering Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of clean Utilization of Complex Non-Ferrous Metal Resources Kunming University of Science and TechnologyKunming 650093China

This paper proposes luteolin(LUT)as a novel depressant for the flotation-based separation of scheelite and calcite in a sodium oleate(NaOL)*** suitability of LUT as a calcite depressant is confirmed through micro-flotation *** pH=9,with LUT concentration of 50 mg·L^(-1) and NaOL concentration of 50 mg·L^(-1),scheelite recovery reaches 80.3%.Calcite,on the other hand,exhibits a recovery rate of 17.6%,indicating a significant difference in floatability between the two ***,the surface modifica-tions of scheelite and calcite following LUT treatment are characterized using adsorption capacity testing,Zeta potential analysis,Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),and atomic force microscopy(AFM).The study in-vestigates the selective depressant mechanism of LUT on *** capacity testing and Zeta potential analysis demonstrate sub-stantial absorption of LUT on the surface of calcite,impeding the further adsorption of sodium oleate,while its impact on scheelite is ***-IR and XPS analyses reveal the selective adsorption of LUT onto the surface of calcite,forming strong chemisorption bonds between the hydroxyl group and calcium ions *** directly illustrates the distinct adsorption densities of LUT on the two miner-al ***,LUT can effectively serve as a depressant for calcite,enabling the successful separation of scheelite and calcite.

关键词： scheelite calcite luteolin flotation depressant separation

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Nickel-modified In_(2)O_(3) with inherent oxygen vacancies for CO_(2) hydrogenation to methanol

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Science China Chemistry 2024年第5期67卷 1715-1728页

作者： Zixuan Zhou Yuchen Wang Yuanjie Bao Haiyan Yang Jiong Li Chunran Chang Shenggang Li Peng Gao CAS Key Laboratory of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China University of Chinese Academy of Sciences Beijing 100049China School of Physical Science and technology ShanghaiTech UniversityShanghai 201210China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Shaanxi Key Laboratory of Low Metamorphic coal clean Utilization School of Chemistry and Chemical EngineeringYulin UniversityYulin 719000China

Methanol synthesis is one of the most important industrially-viable approaches for carbon dioxide(CO_(2)) utilization, as the produced methanol can be used as a platform chemical for manufacturing green fuels and chemicals. The In_(2)O_(3) catalysts are ideal for sustainable methanol synthesis and have received considerable attention. Herein, Co-, Ni-and Cu-modified In_(2)O_(3) catalysts were fabricated with high dispersion and high stability to improve the hydrogenation performance. The Ni-promoted In_(2)O_(3) catalyst in the form of high dispersion possessed the largest amount of oxygen vacancies and the strongest ability for H_(2) activation, leading to the highest CO_(2) conversion and space time yield of methanol of 0.390 g_(Me OH)g_(cat)^(-1)h^(-1) with CH_(3)OH selectivity of 68.7%. In addition, the catalyst exhibits very stable performance over 120 h on stream, which suggests the promising prospect for industrial applications. Further experimental and theoretical studies demonstrate that surface Ni doping promotes the formation of oxygen defects on the In_(2)O_(3) catalyst, although it also results in lower methanol selectivity. Surprisingly, subsurface Ni dopants are found to be more beneficial for methanol formation than surface Ni dopants, so the Nipromoted In_(2)O_(3)catalyst with a lower surface Ni content at the similar Ni loading can reach higher methanol selectivity and productivity. This work thus provides theoretical guidance for significantly improving the CO_(2) reactivity of In_(2)O_(3)-based catalysts while maintaining high methanol selectivity.

关键词： carbon dioxide hydrogenation methanol synthesis indium oxides Ni doping sites transition metal promoters

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Study of plasma parameters of coaxial plasma source using triple Langmuir probe and Faraday cup diagnostics

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Plasma Science and technology 2024年第4期26卷 94-100页

作者： Sunil KANCHI Rohit SHUKLA Archana SHARMA Pulsed Power and Electromagnetics Division Bhabha Atomic Research CentreVisakhapatnam 531011India Homi Bhabha National Institute Mumbai 400085India Beam technology Development group Bhabha Atomic Research CentreMumbai 400085India

Coaxial plasma guns are a type of plasma source that produces plasma which propagates radially and axially controlled by the shape of the ground electrode, which has attracted much interest in several applications. In this work, a 120° opening angle of CPG nozzle is used as a plasma gun configuration that operates at the energy of 150 J. The ionization of polyethylene insulator between the electrodes of the gun produces a cloud of hydrogen and carbon *** triple Langmuir probe and Faraday cup are used to measure plasma density and plasma temperature. These methods are used to measure the on-axis and off-axis plasma divergence of the coaxial plasma gun. The peak values of ion densities measured at a distance of 25 mm on-axis from the plasma gun are(1.6±0.5)×10^(19)m^(-3)and(2.8±0.6)×10^(19)m^(-3)for hydrogen and carbon plasma respectively and the peak temperature is 3.02±0.5 eV. The mean propagation velocity of plasma is calculated using the transit times of plasma at different distances from the plasma gun and is found to be 4.54±0.25 cm/μs and 1.81±0.18 cm/μs for hydrogen and carbon plasma respectively. The Debye radius is obtained from the measured experimental data that satisfies the thin sheath approximation. The shot-to-shot stability of plasma parameters facilitates the use of plasma guns in laboratory experiments. These types of plasma sources can be used in many applications like plasma opening switches, plasma devices, and as plasma sources.

关键词： coaxial plasma source triple Langmuir probe Faraday cup plasma density plasma temperature

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