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学者姓名:敬登伟
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Abstract :
How to efficiently convert solar radiation into energy sources for easy storage and consumption is an urgent issue. Although concentrated photovoltaics can achieve high efficiency, it places higher demands on the optical system and heat management. Herein, a new design is presented where a liquid spherical lens acts as a secondary optical element of the concentrating solar system, refracting the light beam while participating in spectral beam splitting. The radiation energy unavailable for solar cells is harvested by the liquid spherical lens through spectral beam splitting which serves to raise the temperature of the electrolyte. Compared with the conventional concentrated photovoltaic coupled electrolytic hydrogen production system, the addition of a liquid spherical lens improves the solar cell heat dissipation while increasing the operating temperature of the electrolyzer, achieving higher solar-to-hydrogen efficiency. The system with this design obtains a solar-to-electricity efficiency of 31.7% as verified by indoor experiments. The solar-to-hydrogen efficiency of the system achieved an average value of 22.1% and a benchmark maximum value of 22.7% during 7 h of continuous operation. The solar-tohydrogen efficiency is improved by at least 10% compared to the design that separates the secondary optics from the spectral beam-splitting filter. Compared with existing systems employing commercial CPV modules, the efficiency is improved by at least 6% benefiting from the rational distribution of the spectrum by the liquid spherical lens.
Keyword :
Concentrated photovoltaic Hydrogen Secondary optical element Spectral beam -splitting filter thermal system
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GB/T 7714 | Zhu, Yizhou , Ma, Benchi , He, Baichuan et al. Liquid spherical lens as an effective auxiliary optical unit for CPV/T system with remarkable hydrogen production efficiency [J]. | APPLIED ENERGY , 2023 , 334 . |
MLA | Zhu, Yizhou et al. "Liquid spherical lens as an effective auxiliary optical unit for CPV/T system with remarkable hydrogen production efficiency" . | APPLIED ENERGY 334 (2023) . |
APA | Zhu, Yizhou , Ma, Benchi , He, Baichuan , Ma, Xinyu , Jing, Dengwei . Liquid spherical lens as an effective auxiliary optical unit for CPV/T system with remarkable hydrogen production efficiency . | APPLIED ENERGY , 2023 , 334 . |
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Understanding of diffusio-osmosis, the flow induced by a solute gradient acting in narrow interfacial layers at a nanoscale solid-liquid interface, is of great value in view of the increasing importance of micro- and nano-fluidic devices and self-propelling particles. Using molecular dynamics simulations, we employ an appropriate strategy for direct simulation of diffusio-osmosis flows, mimicking a realistic experiment without any assumed external forces. It allows us to obtain reliable flow details, which are hard to obtain in experiments. We found that the solvent-wall interaction, previously overlooked in the classical paradigm, plays a critical role in the diffusio-osmosis process. In particular, diffusio-osmosis is controlled by the interaction difference between the solute-wall and solvent-wall. When the solute-wall interaction is stronger (weaker) than the solvent-wall, a surface excess (depletion) of solute particles on the solid-liquid interface is formed, which induces diffusio-osmosis flow towards a low (high) concentration. We modified the classical Derjaguin expression to include the effect of nanoscale hydrodynamics boundary conditions for the accurate prediction of diffusio-osmosis characteristics. Overall, our results provide clear guidance for controlling fluid flow and manipulating the motion of colloids under tunable solute concentrations.
Keyword :
diffusio-osmosis interfacial flow molecular dynamics nanofluidics
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GB/T 7714 | Wang, Xin , Jing, Dengwei . Directional manipulation of diffusio-osmosis flow by design of solute-wall and solvent-wall interactions [J]. | JOURNAL OF PHYSICS D-APPLIED PHYSICS , 2022 , 55 (14) . |
MLA | Wang, Xin et al. "Directional manipulation of diffusio-osmosis flow by design of solute-wall and solvent-wall interactions" . | JOURNAL OF PHYSICS D-APPLIED PHYSICS 55 . 14 (2022) . |
APA | Wang, Xin , Jing, Dengwei . Directional manipulation of diffusio-osmosis flow by design of solute-wall and solvent-wall interactions . | JOURNAL OF PHYSICS D-APPLIED PHYSICS , 2022 , 55 (14) . |
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Abstract :
Ultrasonic field can lead to cavitation bubbles explosion, which rises a high-frequency oscillation and generates a high-frequency current in semiconductor nanoparticles in suspension. However, the effect of nanoparticle morphology on ultrasonic-triggered H-2 production is still unclear. To this end, herein, nanorods CeO2 (nrCeO2), CeO2 nanocubes (ncCeO(2)), and CeO2 nanospheres (nsCeO(2)) were successfully synthesized. Among them, one-dimensional nrCeO(2) had the most abundant O-vacancies. As revealed by the COMSOL simulation, nanoparticle deformation was easier in nanorods compared with nanocubes and nanospheres, resulting in more efficient charge separation and facilitating H-2 production reaction in nrCeO(2). In detail, within a 5 h' period, nrCeO(2) presented the highest H-2 production activity of 983.1 mmol g(-1) h(-1) with the positive charge (q+) trapping agent of CH3OH, and that of 278.1 mmol g(-1) h(-1) in pure water. This work presents a new understanding about the relationship between nanoparticle morphology and H-2 production activity, and provides a promising, efficient, and clean H-2 production approach, which can be further extended to multi-field coupling reactor.(C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Keyword :
Cerium Hydrogen Morphology Ultrasonic
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GB/T 7714 | Ai, Chaoqian , Shi, Jinwen , Hu, Songwei et al. Morphologies dependence of hydrogen evolution over CeO2 via ultrasonic triggering [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2022 , 47 (34) : 15149-15159 . |
MLA | Ai, Chaoqian et al. "Morphologies dependence of hydrogen evolution over CeO2 via ultrasonic triggering" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 47 . 34 (2022) : 15149-15159 . |
APA | Ai, Chaoqian , Shi, Jinwen , Hu, Songwei , Li, Jinghua , Luo, Bing , Jing, Dengwei . Morphologies dependence of hydrogen evolution over CeO2 via ultrasonic triggering . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2022 , 47 (34) , 15149-15159 . |
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Abstract :
The impact of nanodroplets on a solid surface is widely encountered in industrial processes. Understanding the processes that occur when nanodroplets impact a rough surface is of great significance, but the mechanism and dynamics of these processes remain unclear due to the limitations of experimental tools and the shortcomings of most macroscale models. This paper describes molecular dynamics simulations conducted to explore these nanoscale processes. The wettability and solid fraction of the textured substrate and the effects of different impact velocities are investigated. We demonstrate that the maximum spreading time can be described as a power law of the Weber number and that the maximum spreading factor increases with increasing surface wettability. Owing to changes in the attraction between the nanodroplets and the textured substrate, the maximum spreading factor also increases as the solid fraction increases. Based on energy analysis, a theoretical model is proposed for predicting the maximum spreading factor, and this is found to be in good agreement with the simulation results. The results of this study provide useful guidance for predicting the dynamics of nanodroplet impacts.
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GB/T 7714 | Sun, Lijun , Pan, Jiaxin , Wang, Xin et al. Molecular dynamics study of nanoscale droplets impacting on textured substrates of variable wettability [J]. | PHYSICS OF FLUIDS , 2022 , 34 (1) . |
MLA | Sun, Lijun et al. "Molecular dynamics study of nanoscale droplets impacting on textured substrates of variable wettability" . | PHYSICS OF FLUIDS 34 . 1 (2022) . |
APA | Sun, Lijun , Pan, Jiaxin , Wang, Xin , Jing, Dengwei . Molecular dynamics study of nanoscale droplets impacting on textured substrates of variable wettability . | PHYSICS OF FLUIDS , 2022 , 34 (1) . |
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Abstract :
Improving efficiency, controlling cost and reducing the temperature of solar cells are great challenges for linear concentrated photovoltaic/thermal systems (LCPV/T). In this work, we report a new design with a linear Fresnel lens as the primary optical element and an additional multi-functioned solar collector tube as the secondary optical element. With such design, the low-cost solar collector tube acts multiple roles simultaneously, i.e., lens, spectral beam-splitting filter and heat collector. It was demonstrated that the addition of such multi-functional solar collector tube in LCPV/T system can significantly increase the irradiation uniformity and decrease the average temperature of photovoltaic (PV) module under the same thermal condition, which results in the improved electricity output performance of PV module. Under the solar irradiance and ambient temperature for a typical daytime, the average electrical, thermal and total energy efficiencies of the proposed system are 11.39%, 64.72% and 76.11%, respectively. Our work should be of guidance for the design of LCPV/T system with high efficiency, long-life and low cost.(c) 2022 Elsevier Ltd. All rights reserved.
Keyword :
Concentrated photovoltaic Secondary optical element Solar collector Spectral beam-splitting filter thermal system
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GB/T 7714 | Zhu, Yizhou , Ma, Benchi , Zeng, Zilong et al. Solar collector tube as secondary concentrator for significantly enhanced optical performance of LCPV/T system [J]. | RENEWABLE ENERGY , 2022 , 193 : 418-433 . |
MLA | Zhu, Yizhou et al. "Solar collector tube as secondary concentrator for significantly enhanced optical performance of LCPV/T system" . | RENEWABLE ENERGY 193 (2022) : 418-433 . |
APA | Zhu, Yizhou , Ma, Benchi , Zeng, Zilong , Lou, Hewei , He, Yi , Jing, Dengwei . Solar collector tube as secondary concentrator for significantly enhanced optical performance of LCPV/T system . | RENEWABLE ENERGY , 2022 , 193 , 418-433 . |
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In order to reveal the heat transfer performance of nanofluids in solar collectors, the thermal conductivity and dynamic viscosity of five kinds of graphene oxide nanofluids, with a mass fraction of 0.002% to 0.01%, were studied in the temperature range of 25-50 degrees C. To ensure the dispersion and stability of the prepared nanofluids, UV-Vis absorption spectrum, zeta potential and particle size distribution were employed for nanofluid characterization. Agglomeration and sedimentation of the prepared nanofluids after standing for 20 days were observed, showing the good stability of the prepared graphene oxide-water nanofluid. The dynamic viscosity and thermal conductivity were measured. They show that with the increase in temperature, the dynamic viscosity of nanofluids decreases and the thermal conductivity increases. With the increase in mass concentration, the viscosity and thermal conductivity are improved. The highest thermal conductivity increase is obtained when the nanofluid concentration is 0.01% and the temperature is 50 degrees C. Finally, and most importantly, considering the inaccuracy of the existing experimental correlations to the predicted values of thermal conductivity, we propose our new mathematical model of correlation and carry out a series of tests to verify its reliability. The experimental correlations with temperature and concentration as independent variables show good agreement and accuracy with the experimental data.
Keyword :
experimental correlation graphene oxide nanofluids thermal conductivity viscosity
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GB/T 7714 | Mei, Xinyu , Sha, Xin , Jing, Dengwei et al. Thermal Conductivity and Rheology of Graphene Oxide Nanofluids and a Modified Predication Model [J]. | APPLIED SCIENCES-BASEL , 2022 , 12 (7) . |
MLA | Mei, Xinyu et al. "Thermal Conductivity and Rheology of Graphene Oxide Nanofluids and a Modified Predication Model" . | APPLIED SCIENCES-BASEL 12 . 7 (2022) . |
APA | Mei, Xinyu , Sha, Xin , Jing, Dengwei , Ma, Lijing . Thermal Conductivity and Rheology of Graphene Oxide Nanofluids and a Modified Predication Model . | APPLIED SCIENCES-BASEL , 2022 , 12 (7) . |
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Plasmonic nanomaterial catalysis is currently at the frontier of photocatalysis, overcoming the limitations of wide bandgap semiconductors for light absorption. Its localized surface plasmon resonance (LSPR) properties allow broad ultraviolet-visible-near infrared ray (UV-vis-NIR) absorption, making it an ideal material for solar energy conversion. Most plasmonic nanostructures rely on precious metals. Although noble metal plasmonic nanomaterials have proven to be one of the strategies for enhancing photocatalytic activity, their expensive cost and limitations in light absorption range have hindered their practical application. As a result, noble-metal free plasmonic nanomaterials have risen to the top of the research priority list. Therefore, this paper reviews the fundamental principles and classification of the LSPR effect of noble-metal free plasmonic nanomaterials in photocatalytic and their recent applications in hydrogen generation, carbon dioxide reduction, and pollutant degradation. Specific cases elucidate the possible working mechanism of enhanced photocatalysis by noble-metal free plasmonic nanomaterials. Finally, the challenges and future opportunities for noble-metal free plasmonic nanomaterials in energy conversion and storage are discussed and envisioned.
Keyword :
localized surface plasmon resonance (LSPR) noble-metal free photocatalysis plasmonic nanomaterials
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GB/T 7714 | Li, Jinghua , Zhang, Yiming , Huang, Yalong et al. Noble-metal free plasmonic nanomaterials for enhanced photocatalytic applications-A review [J]. | NANO RESEARCH , 2022 , 15 (12) : 10268-10291 . |
MLA | Li, Jinghua et al. "Noble-metal free plasmonic nanomaterials for enhanced photocatalytic applications-A review" . | NANO RESEARCH 15 . 12 (2022) : 10268-10291 . |
APA | Li, Jinghua , Zhang, Yiming , Huang, Yalong , Luo, Bing , Jing, Li , Jing, Dengwei . Noble-metal free plasmonic nanomaterials for enhanced photocatalytic applications-A review . | NANO RESEARCH , 2022 , 15 (12) , 10268-10291 . |
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Abstract :
Designing high efficacy photocatalysts is a promising way to improve solar fuel production efficiency. In this work, we prepared a core/shell composite of loose ZnCr layered double hydroxide nanosheets modified CdS nanorods for efficient visible light driven photocatalytic hydrogen production. The highest hydrogen production rate achieved 425.8 mu mol.h(-1) without adding any noble metal cocatalyst under the visible light stimulus, which is 22.4 times that of 1 wt.% Pt-modified CdS. The corresponding apparent quantum yield is 13.9% at 420 nm. It is revealed that the synergistic actions of the interfacial redox shuttle of Cr3+/Cr delta+ and the interfacial electric field enable the efficient separation of photoinduced charge carriers between two components via a Z-scheme energy band configuration. Meanwhile, with the hydrogen evolution contribution of Zn2+, a remarkable improvement in photocatalytic performance was achieved in contrast to bare CdS. This work provides an effective methodology to construct highly efficient and economically viable photocatalysts for solar H-2 production and mechanistic study.
Keyword :
heterojunction hydrogen production interfacial engineering noble metal free photocatalysis
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GB/T 7714 | Luo, Bing , Li, Jinghua , Wang, Wei et al. Boosting photocatalytic hydrogen production via interfacial engineering over a Z-scheme core/shell heterojunction [J]. | NANO RESEARCH , 2022 . |
MLA | Luo, Bing et al. "Boosting photocatalytic hydrogen production via interfacial engineering over a Z-scheme core/shell heterojunction" . | NANO RESEARCH (2022) . |
APA | Luo, Bing , Li, Jinghua , Wang, Wei , Ai, Chaoqian , Zhang, Haihan , Zhao, Yuxin et al. Boosting photocatalytic hydrogen production via interfacial engineering over a Z-scheme core/shell heterojunction . | NANO RESEARCH , 2022 . |
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Photocatalytic hydrogen evolution is one promising method for solar energy conversion, but the rapid charge recombination limits its efficiency. To this end, in this work, grain size, and hence the charge carrier migration path, is reduced by lowering the synthesis temperature of two-dimensional visible light-responsive La2NiO4 perovskite. Interestingly, the hydrogen yield for the piezoelectric response of La2NiO4 under only 40 kHz ultrasonic vibration is as high as 680 mu mol h(-1) g(-1), which is 80 times that under only 600 mW cm(-2) visible light irradiation. More surprisingly, the hydrogen production rate under both light illumination and ultrasonic vibration is 129 times higher than under visible light irradiation alone. Clearly, a synergistic effect exists between piezocatalysis and photocatalysis. The hydrogen production activity of the samples with water splitting can reach 1097 mu mol h(-1) g(-1) without any sacrificial reagent or co-catalyst, when the light intensity reaches about 1000 mW cm(-2), which is a much higher hydrogen evolution rate by piezo-photocatalysis than is achieved by either piezocatalysis or photocatalysis individually. Further analysis indicates that the internal electric field generated by deformation of the La2NiO4 edge under piezoelectric action facilitates the directional separation and migration of photogenerated charges, which in turn significantly enhances the efficiency of use of photogenerated charges for hydrogen production. The investigation here provides a novel approach to design a new reaction system for hydrogen production by coupling multiple external physical fields.
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GB/T 7714 | Ma, Xinyu , Gao, Yangfei , Yang, Bian et al. Enhanced charge separation in La2NiO4 nanoplates by coupled piezocatalysis and photocatalysis for efficient H-2 evolution [J]. | NANOSCALE , 2022 , 14 (18) : 7083-7095 . |
MLA | Ma, Xinyu et al. "Enhanced charge separation in La2NiO4 nanoplates by coupled piezocatalysis and photocatalysis for efficient H-2 evolution" . | NANOSCALE 14 . 18 (2022) : 7083-7095 . |
APA | Ma, Xinyu , Gao, Yangfei , Yang, Bian , Lou, Xiaojie , Huang, Jianbing , Ma, Lijing et al. Enhanced charge separation in La2NiO4 nanoplates by coupled piezocatalysis and photocatalysis for efficient H-2 evolution . | NANOSCALE , 2022 , 14 (18) , 7083-7095 . |
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Besides their wide existence in various industrial processes, nanoscale particle suspensions are also the important media for some emerging technologies such as photocatalytic hydrogen production. The circulating flow properties of the nanoparticles in the fluid are of great concern for their practical use. In our study, a modified experimental system was set up based on Malvern laser particle analyzer that can estimate the nanoparticle concentration and size distribution in a laminar nanoparticle circulating flow. We found that the particle concentration and size distribution were periodical oscillation with time in such flow. Understanding the oscillation mechanism is capable of promote the energy efficiency of photocatalytic hydrogen production. A simulation based on Discrete Element Method (DEM) was conducted to understand this particular oscillation mechanism by studying the single particle movement and trajectory properties in the solid-liquid suspension. The simulation results agree well with the tendency obtained by the experimental results and are capable of better understanding the oscillation characteristics. The simulation results also reveal that the nanoparticles tend to gather in the middle region (the higher velocity region) of the tube after several cycles. Moreover the gravity is of great significance in the circulating flow of solid-liquid suspension because the particle swarms tend to distribute a little below the axial center line of the straight tube. These obtained results are credible for understanding the nanoscale particle transport phenomenon in many natural or industrial processes. In particular, our results are helpful for the understanding and effective control of the movement and distribution of photocatalyst particles in the tubular photocatalytic reactor, which is believed to significantly affect the incident radiation distribution and finally the energy conversion efficiency of the photocatalytic process. © 2020 Hydrogen Energy Publications LLC
Keyword :
Conversion efficiency Energy efficiency Finite difference method Hydrogen production Laminar flow Nanoparticles Oscillating flow Size distribution Suspensions (fluids)
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GB/T 7714 | Geng, Jiafeng , Tang, Junwang , Cai, Wenfang et al. Periodical oscillation of particle-laden laminar flow within a tubular photocatalytic hydrogen production reactor predicted by discrete element method [J]. | International Journal of Hydrogen Energy , 2021 , 46 (15) : 9653-9665 . |
MLA | Geng, Jiafeng et al. "Periodical oscillation of particle-laden laminar flow within a tubular photocatalytic hydrogen production reactor predicted by discrete element method" . | International Journal of Hydrogen Energy 46 . 15 (2021) : 9653-9665 . |
APA | Geng, Jiafeng , Tang, Junwang , Cai, Wenfang , Wang, Yechun , Jing, Dengwei , Guo, Liejin . Periodical oscillation of particle-laden laminar flow within a tubular photocatalytic hydrogen production reactor predicted by discrete element method . | International Journal of Hydrogen Energy , 2021 , 46 (15) , 9653-9665 . |
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