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Chinese Chemical Letters 2024年第4期35卷 160-165页

作者： Wengao Zeng Yuchen Dong Xiaoyuan Ye Ziying Zhang Tuo Zhang Xiangjiu Guan Liejin Guo International Research Center for renewable energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

Achieving a high carrier migration efficiency by constructing built-in electric field is one of the promising approaches for promoting photocatalytic activity. Herein, we have designed a donor-acceptor(D-A) crystalline carbon nitride(APMCN) with 4-amino-2,6-dihydroxypyrimidine(AP) as electron donor, in which the pyrimidine ring was well embedded in the heptazine ring via hydrogen-bonding effect during hydrothermal process. The APMCN shows superior charge-transfer due to giant built-in electric field(5.94times higher than pristine carbon nitride), thereby exhibiting excellent photocatalytic H_(2) evolution rate(1350 μmol/h) with a high AQY(62.8%) at 400 nm. Mechanistic analysis based on detailed experimental investigation together with theoretical analysis reveals that the excellent photocatalytic activity is attributed to the promoted charge separation by the giant internal electric field originated from the D–A structure.

关键词： Crystalline carbon nitride Built-in electric field Donor-acceptor structure Photocatalysis Hydrogen production

Stable α-CsPbI3 with extremely red emission for expanding the color gamut

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Science China(Information Sciences) 2024年第5期67卷 311-317页

作者： Yong ZHANG Xin WEI Lei GAO Weijie ZHAO Changjiu SUN Junli WEI Mingjian YUAN Zhenhua NI Junpeng LU Hongwei LIU School of Physics and key laboratory of MEMS of the Ministry of Education Southeast University key laboratory of Advanced energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage Center (RECAST) College of Chemistry Nankai University Jiangsu key Lab on Opto-Electronic Technology School of Physics and TechnologyNanjing Normal University

The wider color gamut represents the better reproducibility of the real natural colors. Perovskite materials exhibit promising potential in full-color wide-gamut displays because of the wide tunability and high saturability of their photon emission. However, the full-color wide gamut(>100% Rec.2020) has not been constructed due to the lack of the extreme red primary color(～700 nm). Herein, the widest color gamut is realized, whereinα-CsPbI3 is used to generate the extreme red primary color. An in-situ encapsulation approach is advised to stabilizeα-CsPbI3 at room temperature by means of polyvinylpyrrolidone(PVP).Theα-CsPbI3 encapsulated by PVP(denoted as P-CPI) shows highly saturated(FWHM(full width at half maximum) ～28 nm) and extremely(～697 nm) red emission. The green emission is provided by P-CPBr(CsPbBr3 with PVP) which is also synthesized using the universal in-situ encapsulation approach. With the assistance of a commercial Ga N chip, the RGB gamut is extended to the widest(151% NTSC, 113%Rec.2020).

关键词： all-inorganic perovskite wide color gamut LED display carrier recombination

A spatiotemporal evolution model of a short-circuit arc to a secondary arc based on the improved charge simulation method

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Plasma Science and Technology 2024年第1期26卷 62-73页

作者：丛浩熹王宇轩乔力盼苏文晶李庆民 State key laboratory of Alternate Electrical Power System with renewable energy Sources North China Electric Power UniversityBeijing 102206People’s Republic of China

The initial shape of the secondary arc considerably influences its subsequent shape.To establish the model for the arcing time of the secondary arc and modify the single-phase reclosing sequence,theoretical and experimental analysis of the evolution process of the short-circuit arc to the secondary arc is critical.In this study,an improved charge simulation method was used to develop the internal-space electric-field model of the short-circuit arc.The intensity of the electric field was used as an independent variable to describe the initial shape of the secondary arc.A secondary arc evolution model was developed based on this model.Moreover,the accuracy of the model was evaluated by comparison with physical experimental results.When the secondary arc current increased,the arcing time and dispersion increased.There is an overall trend of increasing arc length with increasing arcing time.Nevertheless,there is a reduction in arc length during arc ignition due to short circuits between the arc columns.Furthermore,the arcing time decreased in the range of 0°-90°as the angle between the wind direction and the x-axis increased.This work investigated the method by which short-circuit arcs evolve into secondary arcs.The results can be used to develop the secondary arc evolution model and to provide both a technical and theoretical basis for secondary arc suppression.

关键词： short-circuit arc secondary arc stochasticity improved charge simulation method arc time

Amino acids modified nanoscale zero-valent iron:Density functional theory calculations,experimental synthesis and application in the Fenton-like degradation of organic solvents

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Journal of Environmental Sciences 2024年第1期135卷 296-309页

作者： Xingchen Yang Fucheng Ming Jianlong Wang Lejin Xu Department of Nuclear Engineering and Technology School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China China-EU Institute for Clean and renewable energy Huazhong University of Science and TechnologyWuhan 430074China Institute of Nuclear and New energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China Beijing key laboratory of Radioactive Wastes Treatment Tsinghua UniversityBeijing 100084China

To improve the adsorption and catalytic performance of heterogeneous Fenton-like catalysts for oil wastes,amino acids were used to modify nanoscale zero-valent iron(AA@Fe^(0)),which were applied in the Fenton-like degradation of organic solvents(tributyl phosphate and n-dodecane,named TBP and DD).Twelve amino acids,i.e.,glycine(Gly),alanine(Ala),leucine(Leu),proline(Pro),phenylalanine(Phe),methionine(Met),cysteine(Cys),asparagine(Asn),serine(Ser),glutamic acid(Glu),lysine(Lys)and arginine(Arg),were selected and calculated by density functional theory(DFT).The optimized structure,charge distribution,the highest occupied molecular orbital(HOMO),the lowest unoccupied molecular orbital(LUMO),interaction region indicator(IRI)isosurface map and adsorption energy of AA@Fe^(0),AA@Fe^(0)-TBP and AA@Fe^(0)-DD were studied,which indicated that Fe is more likely to approach and charge transfer with-COO and-NH_(3) on theα-carbon of amino acids.There is strong attraction between Fe and–COO,and Van der Waals force between Fe and-NH_(3),respectively.In the interaction of AA@Fe^(0)with TBP and DD,Van der Waal force plays an important role.AA@Fe^(0)was synthesized in laboratory and characterized to investigate physicochemical properties.In Fenton-like degradation of organic solvents,the change of COD in water phase during the degradation process as well as the volume of the organic phase after the reaction were investigated.The results of calculations combined with experiments showed that Ser-modified Fe^(0)performed the best in these amino acids,with 98%removal of organic solvents.A possible catalytic mechanism was proposed in which amino acids acted a linking role between Fe and organic solvents,activating H_(2)O_(2)to generate hydroxyl radicals for the degradation of organic solvents.

关键词： Amino acids Nanoscale zero-valent iron Density functional theory Organic solvents Fenton-like degradation

Intramolecular Hydrogen Bond Improved Durability and Kinetics for Zinc‑Organic Batteries

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Nano-Micro Letters 2024年第3期16卷 138-148页

作者： Tianjiang Sun Jun Pan Weijia Zhang Xiaodi Jiang Min Cheng Zhengtai Zha Hong Jin Fan Zhanliang Tao key laboratory of Advanced energy Materials Chemistry(Ministry of Education) Renewable Energy Conversion and Storage CenterCollege of ChemistryNankai UniversityHaihe Laboratory of Sustainable Chemical TransformationsTianjin 300071People’s Republic of China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore Shanghai key laboratory of Special Artificial Microstructure Materials and Technology School of Physics Science and EngineeringTongji UniversityShanghai 200092People’s Republic of China

Organic compounds have the advantages of green sustainability and high designability,but their high solubility leads to poor durability of zinc-organic batteries.Herein,a high-performance quinone-based polymer(H-PNADBQ)material is designed by introducing an intramolecular hydrogen bonding(HB)strategy.The intramolecular HB(C=O⋯N-H)is formed in the reaction of 1,4-benzoquinone and 1,5-naphthalene diamine,which efficiently reduces the H-PNADBQ solubility and enhances its charge transfer in theory.In situ ultraviolet-visible analysis further reveals the insolubility of H-PNADBQ during the electrochemical cycles,enabling high durability at different current densities.Specifically,the H-PNADBQ electrode with high loading(10 mg cm^(-2))performs a long cycling life at 125 mA g^(-1)(>290 cycles).The H-PNADBQ also shows high rate capability(137.1 mAh g^(−1)at 25 A g^(−1))due to significantly improved kinetics inducted by intramolecular HB.This work provides an efficient approach toward insoluble organic electrode materials.

关键词： Zn-organic batteries H-PNADBQ polymer Intramolecular hydrogen bond Reduced solubility Improvedπ-conjugated level

Function-reversible facets enabling SrTiO_(3)nanocrystals for improved photocatalytic hydrogen evolution

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Frontiers in energy 2024年第1期18卷 101-109页

作者： Bin WANG Bei AN Xiaoqian LI Shaohua SHEN School of Physics Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter(Ministry of Education)Key Laboratory of Shaanxi for Advanced Materials and Mesoscopic PhysicsXi’an Jiaotong UniversityXi’an 710049China International Research Center for renewable energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

It has been widely reported that,for faceted nanocrystals,the two adjacent facets with different band levels contribute to promoted charge separation,and provide active sites for photocatalytic reduction and oxidation reaction,respectively.In such cases,only one family of facets can be used for photocatalytic hydrogen evolution.Herein,by using SrTiO_(3)nanocrystals enclosed by{023}and{001}facets as a model photocatalyst,this paper proposed a strategy to achieve the full-facets-utilization of the nanocrystals for photocatalytic hydrogen via chemically depositing Pt nanoparticles on all facets.The photo-deposition experiment of CdS provided direct evidence to demonstrate that the{023}facets which were responsible for photooxidation reaction can be function-reversed for photocatalytic hydrogen evolution after depositing Pt nanoparticles,together with the{001}facets.Thus,the full-facets-utilization led to a much-improved activity for photocatalytic hydrogen,in contrast to those SrTiO_(3)nanocrystals with only{001}facets deposited by Pt nanoparticles via a photo-deposition method.

关键词： SrTiO_(3)nanocrystals crystal facets photocatalysis hydrogen evolution

Effects of baffle position in serpentine flow channel on the performance of proton exchange membrane fuel cells

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Chinese Journal of Chemical Engineering 2024年第5期69卷 250-262页

作者： Guodong Xia Xiaoya Zhang Dandan Ma MOE key laboratory of Enhanced Heat Transfer and energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of TechnologyBeijing 100124China

This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstream(Case 3),downstream(Case 4),and the entire cathode flow channel(Case 5)to study the effects of baffle position on mass transport,power density,net power,etc.Moreover,the effects of back pressure and humidity on the voltage were investigated.Results showed that compared to smooth channels,the oxygen and water transport facilitation at the diffusion layer-channel interface were added 11.53%-20.60%and 7.81%-9.80%at 1.68 A·cm^(-2)by adding baffles.The closer the baffles were to upstream,the higher the total oxygen flux,but the lower the flux uniformity the worse the water removal.The oxygen flux of upstream baffles was 8.14%higher than that of downstream baffles,but oxygen flux uniformity decreased by 18.96%at 1.68 A·cm^(-2).The order of water removal and voltage improvement was Case 4>Case 5>Case 3>Case 2>Case *** power of Case 4 was 9.87%higher than that of the smooth channel.To the Case 4,when the cell worked under low back pressure or high humidity,the voltage increments were higher.The potential increment for the back pressure of 0 atm was 0.9%higher than that of 2 atm(1 atm=101.325 kPa).The potential increment for the humidity of 100%was 7.89%higher than that of 50%.

关键词： Proton exchange membrane fuel cell Baffle position Mass transfer Net power Uniformity Voltage increment

Structural Optimization of the Inlet Header of Supercritical Carbon Dioxide Printed Circuit Board Heat Exchanger

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Journal of Thermal Science 2024年第4期33卷 1458-1467页

作者： WANG Yanquan LU Yuanwei WANG Yuanyuan HAN Xinlong WU Yuting GAO Qi MOE key laboratory of Enhanced Heat Transfer and energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of Technology

Supercritical carbon dioxide printed circuit board heat exchangers are expected to be applied in third-generation solar thermal power generation.However,the uniformity of supercritical carbon dioxide entering the heat exchanger has a significant impact on the overall performance of the heat exchanger.In order to improve the uniformity of flow distribution in the inlet header,this article studies and optimizes the inlet header of a printed circuit board heat exchanger through numerical simulation.The results indicate that when supercritical carbon dioxide flows through the header cavity,eddy currents will be generated,which will increase the uneven distribution of flow rate,while reducing the generation of eddy currents will improve the uniform distribution of flow rate.When the dimensionless factor of the inlet header is 6,the hyperbolic configuration is the optimal structure.We also reduced the eddy current region by adding transition segments,and the results showed that the structure was the best when the dilation angle was 10°,which reduced the non-uniformity by 21% compared to the hyperbolic configuration,providing guidance for engineering practice.

关键词： third-generation solar thermal power generation inlet header PCHE numerical simulation

Numerical Study on Heat Transfer and Frictional Resistance of Two Types of Molten Salts in Straight Channels and Supercritical Carbon Dioxide in Airfoil Channels

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Journal of Thermal Science 2024年第4期33卷 1443-1457页

作者： WANG Yanquan LU Yuanwei GAO Qi LI Feng MA Yancheng WANG Yuanyuan WU Yuting MOE key laboratory of Enhanced Heat Transfer and energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of Technology

Molten salt and supercritical carbon dioxide（sCO2） are considered to be one of the most promising combined heat transfer refrigerants for third-generation solar thermal power generation.To evaluate the potential of chloride salts and carbonates in third-generation solar thermal power generation,this paper uses molten salts and sCO2as the working media of printed circuit board heat exchangers（PCHE）,and uses numerical simulation to study the heat transfer and friction of PCHE channels with different molten salts and sCO2,and establishes predictive correlations respectively.A local heat transfer and friction study was conducted on the sCO2side of the airfoil channel,and it was found that the inlet mass flow rate has a significant impact on it,while the inlet temperature has a relatively small impact.A comprehensive comparison was made between the heat transfer and friction of two molten salts,and the comprehensive performance of chloride salts was 70%-80% higher than that of carbonates.The results indicate that the potential of chloride salts in third-generation solar thermal power generation is much greater than that of carbonates.

关键词： third generation solar thermal power generation sCO 2 PCHE molten salt

Vinyltrimethylsilane as a novel electrolyte additive for improving interfacial stability of Li-rich cathode working in high voltage

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Chinese Chemical Letters 2024年第2期35卷 534-538页

作者： Bing Jiang Hao Li Bi Luo Lehao Liu Lihua Chu Qiaobao Zhang Meicheng Li State key laboratory of Alternate Electrical Power System with renewable energy Sources School of New EnergyNorth China Electric Power UniversityBeijing 102206China State key laboratory of Physical Chemistry of Solid Surfaces College of MaterialsXiamen UniversityXiamen 361005China

Boosting the interfacial stability between electrolyte and Li-rich cathode material at high operating voltage is vital important to enhance the cycling stability of Li-rich cathode materials for high-performance Li-ion batteries.In this work,vinyltrimethylsilane as a new type of organic silicon electrolyte additive is studied to address the interfacial instability of Li-rich cathode material at high operating voltage.The cells using vinyltrimethylsilane additive shows the high capacity retention of 73.9%after 300 cycles at 1 C,whereas the cells without this kind of additive only have the capacity retention of 58.9%.The improvement of stability is mainly attributed to the additive helping to form a more stable surface film for Li-rich cathode material,thus avoiding direct contact between the electrolyte and the cathode material,slowing down the dissolution of metal ions and the decomposition of the electrolyte under high operating voltage.Our findings in this work shed some light on the design of stable cycling performance of Li-rich cathode toward advanced Li-ion batteries.

关键词： Vinyltrimethylsilane Electrolyte additive Li-rich cathode Interfacial stability Capacity retention