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Science China Materials 2025年第5期68卷 1561-1569页

作者：黄富霞刘一菲王峰刘亚郭烈锦 International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University

BiOI材料在光催化CO2还原领域展现出巨大潜力,但其较弱的CO2的活化能力与较差的载流子分离效率严重制约了光催化转化效率.本研究通过构建富含丰富晶体缺陷的BiOI基光催化剂有效地提高了其光催化性能.结合X射线衍射、拉曼、和高分辨透射... 详细信息

BiOI材料在光催化CO2还原领域展现出巨大潜力,但其较弱的CO2的活化能力与较差的载流子分离效率严重制约了光催化转化效率.本研究通过构建富含丰富晶体缺陷的BiOI基光催化剂有效地提高了其光催化性能.结合X射线衍射、拉曼、和高分辨透射电子显微镜表征,证实了BiOI-LD和BiOI-TC催化剂中分别存在晶格畸变和孪晶结构缺陷.紫外-可见光谱、微孔与化学吸附分析,以及光致发光光谱表征结果表明,晶体缺陷的引入显著增强了光催化剂的光吸收能力、CO2吸附能力、载流子传输效率及寿命.电子顺磁共振光谱进一步证实BiOI-TC中超氧自由基的生成量显著提升,表明晶体缺陷构筑有效增强了催化剂表面反应活性.因此, BiOI-TC催化剂实现了6.2μmol g-1h-1的CH3CH2OH生成速率,且选择性达到100%.通过原位FTIR研究识别了生成CH3CH2OH的关键中间体（*CO、*COCO、*CHO和*CH2）,并揭示BiOI-LD中C2H6的生成与*CH3中间体的形成密切相关.

关键词： photocatalysis CO2 reduction BiOI crystal defects CH3CH2OH C2H6

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Performance comparison investigation on different pulse tube position heat pumps with power recovery displacer

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International Journal of Refrigeration 2025年 176卷 1-16页

作者： Zhu, Shenglin Chen, Xi Zhu, Yifan Qi, Yingxia School of Energy and Power Engineering University of Shanghai for Science and Technology 516 Jungong Road Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology 516 Jungong Road Shanghai200093 China

Spacecraft waste heat is dissipated into space primarily by radiation. To improve the heat dissipation efficiency of spacecraft radiators in high-temperature environments and reduce heat wastage in spaceflight thermal control systems, thermoacoustic heat pumps (TAHP) are considered a viable method for increasing radiator cooling temperatures and recovering waste heat. In this study, one-dimensional simulations are used to optimize the geometrical parameters of the 100-watt work recovery thermoacoustic heat pump (WRTAHP) for various pulse tube positions. The performances of the two systems are compared at a cold-end temperature of 293 K and a hot-end temperature of 353 K. The results reveal that a heating capacity of 256 W with a relative Carnot efficiency of 35.01 % is achieved for the pulse tube front-type thermoacoustic heat pump (FTTAHP), whereas the pulse tube back-type thermoacoustic heat pump (BTTAHP) obtains a heating capacity of 225 W with a relative Carnot efficiency of 30.59 %. As the cold-end temperature decreases, the coefficient of performance is reduced for FTTAHP, while the performance of BTTAHP shows a substantial improvement. At a cold end temperature of 233 K and a hot-cold end temperature difference of 60 K, a heating capacity of 268 W with a relative Carnot efficiency of 50.57 % is achieved for BTTAHP. Furthermore, the heating capacity of the BTTAHP is not significantly increased by adopting the active phase adjustment structure. In summary, the FTTAHP is suitable for spacecraft radiator applications and avoids high temperatures affecting compressor operation, whereas the BTTAHP is better suited for low-temperature heating. © 2025 Elsevier Ltd and IIR

关键词： Waste heat utilization

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Concurrently Boosting Activity and Stability of Oxygen Reduction Reaction Catalysts via Judiciously Crafting Fe-Mn Dual Atoms for Fuel Cells

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Nano-Micro Letters 2025年第4期17卷 275-289页

作者： Lei Zhang Yuchen Dong Lubing Li Yuchuan Shi Yan Zhang Liting Wei Chung-Li Dong Zhiqun Lin Jinzhan Su International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China Department of Physics Tamkang UniversityNew Taipei CityTaiwan 25137People’s Republic of China Department of Chemical and Biomolecular Engineering National University of SingaporeEngineering Drive 4Singapore 117585Singapore

The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel ***,we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe-Mn dualmetal sites on N-doped carbon(denoted(FeMn-DA)-N-C)for both anion-exchange membrane fuel cells(AEMFC)and proton exchange membrane fuel cells(PEMFC).The(FeMn-DA)-N-C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N_(4)and Mn-N_(4)sites on the carbon surface,yielded via a facile doping-adsorption-pyrolysis *** introduction of Mn carries several advantageous attributes:increasing the number of active sites,effectively anchoring Fe due to effective electron transfer to Mn(revealed by X-ray absorption spectroscopy and density-functional theory(DFT),thus preventing the aggregation of Fe),and effectively circumventing the occurrence of Fenton reaction,thus reducing the consumption of ***(FeMn-DA)-N-C catalysts showcase half-wave potentials of 0.92 and 0.82 V in 0.1 M KOH and 0.1 M HClO_(4),respectively,as well as outstanding *** manifested by DFT calculations,the introduction of Mn affects the electronic structure of Fe,down-shifts the d-band Fe active center,accelerates the desorption of OH groups,and creates higher limiting *** AEMFC and PEMFC with(FeMn-DA)-N-C as the cathode catalyst display high power densities of 1060 and 746 mW cm^(-2),respectively,underscoring their promising potential for practical *** study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.

关键词： Doping-adsorption-pyrolysis Dual-atom catalysts Oxygen reduction reaction Fuel cells

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Multi-objective optimization of 200 kW air centripetal turbine based on artificial neural networks

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International Journal of Advanced Nuclear Reactor Design and Technology 2025年第2期7卷 70-80页

作者： Wang, Zideng Zhang, Yan Leng, Yuyang Lai, Jiabao Wang, Zhenzhen Chen, Weixiong State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The air-Brayton cycle has the characteristics of safety and high efficiency, which can be used as an energy conversion system for mobile small reactors. The air turbine is one of the key components in the cycle system, and improving its performance is of great significance. In this paper, an artificial neural network model combined with a genetic algorithm was used to optimize the rotor of an air centrifugal turbine with axial thrust and efficiency as the objective. The results show that the artificial neural network model can fit the CFD numerical simulation results well, with a coefficient of determination larger than 0.97. Then, after optimizing the artificial neural network model with a genetic algorithm, the total -total efficiency of the air centrifugal turbine was improved by 1.479 %, while the axial thrust was reduced by 1.07 %. © 2025 Xi'an Jiaotong University

关键词： Genetic algorithms

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Effect of H2/CO ratio on non-isothermal reduction behavior and kinetics of vanadium titanomagnetite

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International Journal of Hydrogen Energy 2025年 139卷 69-79页

作者： Shi, Jian Xu, Qiang Lu, Xuyang Cao, Zeshui Kang, Haopeng Chen, Bin Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Hydrogen-based direct reduction of vanadium titanomagnetite is crucial for developing clean and efficient hydrogen metallurgy technology, while existing studies lack systematic research on the impact of H2/CO ratios on the reduction of vanadium titanomagnetite under non-isothermal conditions. This study examines the influence of varying H2/CO ratios on the non-isothermal reduction behavior and kinetics of vanadium titanomagnetite through thermogravimetric analysis (TGA). The results of thermogravimetric experiments show that raising the H2 ratio can significantly lower the initial reduction temperature and accelerate the reduction rate. When H2/(H2+CO) rises from 0 to 1, the initial reduction temperature can be lowered by around 150 °C at a heating rate of 10 °C/min. As the heating rate decreases, the reduction curve shifts to the low-temperature region, and the reduction reaction becomes easier to proceed. The vanadium titanomagnetite reduction activation energy was calculated using the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) model-free kinetic methods, and the activation energy of vanadium titanomagnetite reduction under pure CO atmosphere (H2/(H2 + CO) = 0) was the highest (120.74 kJ/mol by FWO and 107.82 kJ/mol by KAS). As the H2/(H2+CO) ratio increases, the activation energy continuously decreases, effectively reducing the reduction energy barrier of vanadium titanomagnetite. In contrast to an environment of pure CO, the activation energy for the reduction of vanadium titanomagnetite was reduced by 25.47 % (FWO method) or 28.73 % (KAS method) in a pure H2 atmosphere (H2/(H2 + CO) = 1), indicating that an elevated H2 ratio significantly enhanced the reduction of vanadium titanomagnetite. XRD analysis showed that, after the non-isothermal reduction, unreduced iron oxide was still present within the vanadium titanomagnetite under a pure CO atmosphere, while the final reduction product was mainly metallic iron under different H2/CO ratios. Increas

关键词： Activation energy

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A multi-physics model-based approach for macro-structured surface design to enhance heat transfer in R410A flash spray cooling systems

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International Journal of Heat and Mass Transfer 2025年 247卷

作者： Ye, Ying-Dong Lin, Xiang-Wei Zhou, Zhi-Fu Liu, Maochang Chen, Bin Lu, Youjun Jing, Dengwei State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Refrigerant flash spray cooling, which offers high heat flux dissipation at low temperatures, holds significant potential for thermal management of high-power electronic devices. While surface structure design can further amplify heat transfer performance, the lack of systematic methodologies to address the complexities of spray cooling has hindered progress. This study establishes a multi-physics computational framework that couples two-phase flash spray dynamics, liquid film heat transfer, and solid heat conduction to systematically optimize macro-structured surfaces. After validating the model against experimental data, the effects of surface geometry (flat, square, straight and pyramid fins) and dimensional parameters on cooling performance were analyzed. The pyramid structure demonstrated superior performance, achieving a 9 K reduction in surface temperature and a 70 % increase in effective heat transfer coefficient compared to the flat surface. Quantitative analysis revealed that optimal macro-structured design hinges on maximizing effective heat transfer area while ensuring uniform liquid film distribution via controlled droplet dynamics. Further parametric studies on nine pyramid geometries identified a base length of 1 mm and height-to-edge ratio of 0.7 as the optimal configuration, balancing heat transfer enhancement and manufacturing costs through a newly proposed Composite Heat Transfer Factor (CHTF). This work provides a mechanistic framework for designing enhanced surfaces in spray cooling systems, bridging critical gaps in both theoretical understanding and engineering application. © 2025 Elsevier Ltd

关键词： Film cooling

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Numerical study of specific C-shaped heat exchanger using porous medium and coarse mesh coupling method

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International Journal of Thermal Sciences 2025年 210卷

作者： He, Shaopeng Wang, Shiqi Wang, Mingjun Tian, W.X. Qiu, S.Z. Su, G.H. State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

Porous medium method is an effective simplified approach for the heat exchanger simulation when the numerous tubes and complex structures bring unacceptable computational resources to full-scale simulation. However, for the specific C-shaped heat exchanger, the tube side resistance and flow distribution characteristics that significantly affects the heat transfer and natural circulation performance cannot be obtained by the traditional porous medium method coupled with the one-dimensional node model for tube side. It is urgent to develop a new coupling method that can not only simplify modeling and calculation, but also obtain tube side high-resolution flow heat transfer characteristics. This study presents a novel calculation method which couples the porous medium mesh and the tube side coarse mesh. The coupling method was then applied to a typical C-shaped passive residual heat removal heat exchanger (PRHR HX), which is significant to the stable operation and the mitigation of accident conditions in the nuclear power plant. The coupling calculation method was validated against the full-scaled simulation and data from scaled-down experiment. The average relative error of heat transfer power is 2.1 % under steady state conditions. Under transient conditions, the average absolute error of the fluid temperature and wall temperature are less than 6 K. Then the 3D thermal-hydraulic characteristics of PRHR HX was studied. Owing to a greater gravitational pressure head, the mass flow rates in the extended tubes surpass those in the shorter tubes by a relative deviation of 27.4 %. The upper horizontal tube's heat exchange capacity constitutes approximately 70 % of the total power, leading to enhanced natural circulation. The outlet temperatures from various tubes tend to equalize. The boiling area gradually extended down along the heat transfer tubes. Our work would present an innovative calculation method to the numerical study and design optimization of the C-shaped heat

关键词： Nuclear power plants

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Thermal mechanical response analysis of the first wall in laser initial confinement fusion reactors

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International Journal of Advanced Nuclear Reactor Design and Technology 2025年第2期7卷 147-155页

作者： Xinze Li Bingqian Zhang Chengcheng Tong Ronghua Chen Dalin Zhang Wenxi Tian Suizheng Qiu State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an 710049 China

This paper investigates the thermo-mechanical response characteristics of the first wall of a laser initial confinement fusion reactor under periodic transient heat flux loads. The first wall of the reactor experiences extremely high instantaneous heat loads during the target compression process, leading to temperature and thermal stress oscillations, which can cause material fatigue damage. Finite element analysis is employed to model the first wall under various chamber sizes and target energies, and the thermal-mechanical response characteristics of W, W/Cu functional gradient materials, and blanket materials are studied under thermal shock and cyclic loading conditions. The results indicate that W/Cu functional gradient materials can effectively alleviate thermal stresses on the first wall, especially in addressing the stress concentration at the interface. Fatigue life of the first wall is assessed using the Basquin model, and it is found that increasing the chamber size and increasing the target frequency can significantly reduce temperature oscillations and thermal stresses, thus extending the service life of the first wall. This study provides valuable design references for the optimization and design of the first wall in laser initial confinement fusion reactor.

关键词： Laser inertial confinement fusion reactor First wall Heat oscillation Thermal fatigue

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Modification of Anatase TiO2with Amorphous Cu Nanoparticles: An Efficient Photocatalyst for the Reduction of CO2to CO/CH4

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The Journal of Physical Chemistry C 2025年第22期129卷 10083-10093页

作者： Xiong Liu Qulan Zhou Xiaole Chen Shicheng Liu Na Li Zhong Huang Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power Engineering Tsinghua University Beijing 100084 China

Titanium dioxide-based photocatalysts have garnered significant attention for CO2reduction reactions (CO2RR) toward fuel production, with noble metal incorporation markedly enhancing photocatalytic efficiency. However, the development of cost-effective alternatives to expensive metals (e.g., Au, Ag) remains a critical challenge. Herein, amorphous copper nanoparticles (a-Cu NPs) were successfully anchored onto anatase TiO2via a chemical reduction method using Cu(NO3)2·3H2O as the precursor. The optimized 4 wt % a-Cu/TiO2catalyst (4CT) demonstrated remarkable activity, achieving methane and CO production rates of 3.0 and 18.4 μmol·g–1·h–1, respectively, corresponding to 10.0-fold and 7.3-fold enhancements over pristine TiO2. CO2-TPD revealed that the high surface disorder of a-Cu NPs significantly strengthened CO2chemisorption. In situ Fourier transform infrared spectroscopy (FTIR) further indicated that a-Cu loading enabled preferential CO2adsorption over H2O on TiO2surfaces while accelerating the formation of the key intermediate *COOH. This work proposes a synergistic strategy integrating nonprecious metal modification with interfacial engineering, offering a cost-effective pathway to develop high-performance photocatalysts for sustainable CO2conversion.

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Graph neural network-driven prediction of high-performance CO_(2)reduction catalysts based on Cu-based high-entropy alloys

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Chinese Journal of Catalysis 2025年第4期71卷 197-207页

作者： Zihao Jiao Chengyi Zhang Ya Liu Liejin Guo Ziyun Wang International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityShaanxi 710049China School of Chemical Sciences University of AucklandAuckland 1010New Zealand

High-entropy alloy(HEA)offer tunable composition and surface structures,enabling the creation of novel active sites that enhance catalytic performance in renewable energy ***,the inherent surface complexity and tendency for elemental segregation,which results in discrepancies between bulk and surface compositions,pose challenges for direct investigation via density functional *** address this,Monte Carlo simulations combined with molecular dynamics were employed to model surface segregation across a broad range of elements,including Cu,Ag,Au,Pt,Pd,and *** analysis revealed a trend in surface segregation propensity following the order Ag>Au>Al>Cu>Pd>*** capture the correlation between surface site characteristics and the free energy of multi-dentate CO_(2)reduction intermediates,a graph neural network was designed,where adsorbates were transformed into pseudo-atoms at their centers of *** model achieved mean absolute errors of 0.08–0.15 eV for the free energies of C_(2)intermediates,enabling precise site activity *** indicated that increasing the concentration of Cu,Ag,and Al significantly boosts activity for CO and C_(2)formation,whereas Au,Pd,and Pt exhibit negative *** screening stable composition space,promising HEA bulk compositions for CO,HCOOH,and C_(2)products were predicted,offering superior catalytic activity compared to pure Cu catalysts.

关键词： Density functional theory Machine learning CO_(2)reduction High entropy alloys Graph neural network

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