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Efficient degradation of phenol using Sn4+ doped FeOCl as photo-Fenton catalyst
摘要： Sn4+ doped FeOCl has been successfully synthetized as a sunlight-driven photo-Fenton catalyst, which shows that the catalytic activity of Sn4+/FeOCl (1.08% Sn4+ in the Sn4+/FeOCl) is a factor of 11.8 time higher than that of FeOCl. The doping of Sn4+ in FeOCl increases the optical adsorption and surface area of FeOCl. The decreased chemical bond strength of Fe-Cl in Sn4+/FeOCl effectively increases the number of exposed active sites (Fe-site and Sn-site), which boosts the production of ·OH radicals. The Sn-site shows higher catalytic activity than Fe-site. A synergistic mechanism for Sn4+/FeOCl is proposed for the enhanced catalytic performance.
关键词： Solar energy materials,FeOCl,Phenol,Nanocomposites,Fenton reaction,Sn4+
更新于2025-09-23 15:23:52
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Fully Solar-Powered Uninterrupted Overall Water-Splitting Systems
摘要： Extensive research efforts have been recently devoted to the development of self-driven electrocatalytic water-splitting systems to generate clean hydrogen chemical fuels. Currently, self-driven electrocatalytic water-splitting devices are powered by solar cells, which operate intermittently, or by aqueous batteries, which deliver stored electric power, leading to high operating costs and environmental pollution. Thus, a fully solar-powered uninterrupted overall water-splitting system is greatly desirable. Here, the solar cells, stable output voltage of 1.75 V Ni–Zn batteries, and high efficiency zinc–nickel–cobalt phosphide electrocatalysts are successfully assembled together to create a 24 h overall water-splitting system. Specifically, the silicon-based solar cells enable the charging of aqueous Ni–Zn batteries for energy storage as well as providing sufficient energy for electrocatalysis throughout the day; in addition, the high-capacity Ni–Zn batteries offer a steady output voltage for overall water-splitting at night. Such an uninterrupted solar-to-hydrogen system opens up exciting opportunities for the development and applications of renewable energy.
关键词： uninterrupted,solar-powered,water-splitting system,aqueous rechargeable batteries
更新于2025-09-23 15:23:52
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Unidirectional light scattering by up–down Janus dimers composed of gold nanospheres and silicon nanorods
摘要： In this paper, a time-domain finite-difference (FDTD) method is used to simulate the scattering properties of a Janus dimer that a gold nanosphere is putted on the top of a silicon nanorod. We have demonstrated that the Janus dimer exhibits unidirectional scattering in the whole wavelength region of the sunlight. The unidirectionality of the dimer will improve with the height increase of the silicon nanorod and the gap decrease between two adjacent dimers. In our simulation, the forward-to-backward ratio (F/B) of the Janus dimer calculated dividing forward scattering spectra by backward scattering spectra can achieve the maximum of 20 when the height of silicon nanorod is 300 nm. What is more, we have applied the Janus dimers to amorphous silicon thin-film solar cells as antireflection structures. The reflectivity of the solar cells reduces by 39.40% and the short circuit current density improves by 5.04% than those of the reference. Therefore, the Janus dimers has a great application prospect in photovoltaic devices.
关键词： Amorphous silicon solar cells,Janus dimers,Unidirectional scattering,Electric and magnetic dipole resonance
更新于2025-09-23 15:23:52
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Performance improvement of baffle-type solar air collector based on first chamber narrowing
摘要： This paper proposes a novel idea to optimize thermal performance of baffle-type solar air collector by narrowing the first chamber through rearranging the baffles in the collector. The collector with five chambers divided by four baffles was investigated numerically and experimentally, and the mechanism of performance improvement was revealed by flow and heat transfer analysis. The simulation results show that the width of first chamber has significant influence on thermal efficiency, while has little influence on pressure drop. The maximum thermal-efficiency growth rate can be achieved when the width of the first chamber is 200 mm with the total chamber size of 2000 mm × 1000 mm × 120 mm, and the value is up to 16.90% compared with the model with evenly distributed baffles during the Reynolds number ranges from 1.8–5.5 × 10^3. A test rig was developed at the ratio of 1:0.5 to the numerical model. Four collector models were studied under three working conditions, and effectiveness of this method is verified. The results show that the first-chamber narrowing method has relatively stable optimization effect with a thermal-efficiency growth rate ranges from 9.73% to 16.10% in the experiment. It means that this method is not sensitive to scale change and has certain adaptability.
关键词： Experimental verification,Numerical simulation,Performance optimization,First chamber narrowing,Solar air collector
更新于2025-09-23 15:23:52
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Separation of boron from silicon by steam-added electron beam melting
摘要： Removal of boron from silicon is a tough task by traditional directional solidification and vacuum refining techniques, due to its large and inappropriate segregation coefficient and low saturated vapor pressure. At high temperature boron react with oxygen to form volatile boron oxides which can be evaporated. So, the removal procedure of boron from silicon melt is investigated by incorporating a small amount of water vapor above the melted surface. The results show that boron is oxidized to mainly form BO and evaporated with 28% removal efficiency by average. It is considered that oxygen atoms experience a series of physical and chemical processes, such as a chemical reaction in the bulk of the melt, evaporation from the melt surface, transportation across the gas phase and ionization due the electron beam, which is conducive to the continuous removal of boron.
关键词： Electron beam melting,Photovoltaic,Boron removal,Oxygen self-circulating path,Solar-grade silicon
更新于2025-09-23 15:23:52
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Fast-Growing Field of Interfacial Solar Steam Generation: Evolutional Materials, Engineered Architectures, and Synergistic Applications
摘要： The lack of fresh water resources is attracting concern worldwide. Recently, to address this global issue, researchers proposed the heat localization concept for interfacial solar seawater desalination in 2014. Since then, interfacial solar steam generation (ISSG) devices have attracted much attention, due to their potential for achieving highly enhanced optical-thermal conversion through a single interface as compared with traditional solar seawater desalination. To date, the promising prospect of ISSG systems in seawater desalination has stimulated the rapid development of solar desalination technology based on heat localization. To comprehensively recognize ISSG devices and acquire more insights into their design associated with biological relevance, efficiency improvement, and applications, this review summarizes the progresses and prospects of ISSG devices in relation to the evolution of advanced materials, the engineering architecture, the collaborative application, and the current challenges.
关键词： biological relevance,interfacial solar steam generation devices,structure design,applications
更新于2025-09-23 15:23:52
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Determination of the optimal camera distance for cloud height measurements with two all-sky imagers
摘要： All-sky imager based systems can be used to measure a number of cloud properties. Configurations consisting of two all-sky imagers can be used to derive cloud heights for weather stations, aviation and nowcasting of solar irradiance. One key question for such systems is the optimal distance between the all-sky imagers. This problem has not been studied conclusively in the literature. To the best of our knowledge, no previous in-field study of the optimal camera distance was performed. Also, comprehensive modeling is lacking. Here, we address this question with an in-field study on 93 days using 7 camera distances between 494 m and 2562 m and one specific cloud height estimation approach. We model the findings and draw conclusions for various configurations with different algorithmic methods and camera hardware. The camera distance is found to have a major impact on the accuracy of cloud height determinations. For the used 3 megapixel cameras, cloud heights up to 12,000 m and the used algorithmic approaches, an optimal camera distance of approximately 1500 m is determined. Optimal camera distances can be reduced to less than 1000 m if higher camera resolutions (e.g. 6 megapixel) are deployed. A step-by-step guide to determine the optimal camera distance is provided.
关键词： Cloud height measurements,Solar nowcasting,All-sky imagers
更新于2025-09-23 15:23:52
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Hydrogen production via a novel two-step solar thermochemical cycle based on non-volatile GeO2
摘要： Encouraged by recent advances in solar-chemical fuel production, a moderately high-temperature solar thermochemical cycle based on GeO2/Ge is investigated thermodynamically. Since the GeO2/Ge redox has a great oxygen exchange capacity and suffers unfavorable phase change at high temperature, methanothermal reduction is introduced to lower the operation temperature below melting point of redox. The calculated results indicate that reduction conditions of 875 K < T_red < 1200 K and CH4:GeO2 = 2:1 are conducive to achieving high selectivities of H2 and CO. As for the oxidation step, the H2O:Ge ratio of 8:1 is found abundant enough to ensure complete reoxidation of Ge. Isothermal and non-isothermal solar-to-fuel efficiency (η_solarfuel) are compared, where η_solarfuel of 0.47 and isothermal η_solarfuel of 0.28 respectively. In addition, the preferred site of CH4 adsorbing on GeO2 is predicted, and the calculated adsorption energy is lower than that of SnO2, indicating that GeO2 could be a suitable material for substrate before methanothermal reduction.
关键词： Non-volatile redox,Isothermal and nonisothermal operation,Syngas production,Hydrogen production,GeO2/Ge based solar-chemical cycle
更新于2025-09-23 15:23:52
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Numerical and outdoor real time experimental investigation of performance of PCM based PVT system
摘要： Photovoltaic power generation is a suitable option to counter depleting and environmentally hazardous fossil fuels. However, increased cell temperature of the photovoltaic module reduces the electrical performance. Therefore, for enhancing the electrical performance as well as to obtain the useful thermal, a combined photovoltaic thermal system is suitable technology. Furthermore, the addition of phase change materials into photovoltaic thermal systems adds more dual benefits in terms of cooling of PV cell as well as heat storage. Hence, there are still issues to transfer heat from the system efficiently, which cause lower performance of PVT and PVT-PCM systems. In this paper, the aluminium material of thermal collector is used by introducing a novel design to enhance heat transfer performance, which is assembled in PVT and PVT-PCM systems. Experimental validation is carried out for the 3D FEM-based numerical analysis with COMSOL Multiphysics? at 200 W/m2 to 1000 W/m2 varying irradiation levels while keeping mass flow rate fixed at 0.5LPM and inlet water temperature at 32 °C. The experiment is carried out at outdoor free weather conditions with passive cooling of the module by an overhead water tank scheme. A good agreement in numerical and experimental results is achieved through experimental validation. Cell temperature reduction of 12.6 °C and 10.3 °C is achieved from the PV module in case of the PVT-PCM system. The highest value of the electrical efficiency achieved is 13.72 13.56% for PV and 13.85 and 13.74% for PVT numerically and experimentally respectively. Similarly, for PVT-PCM, electrical efficiency is achieved as 13.98 and 13.87% numerically and experimentally respectively. In the case of the PVT system, electrical performance is improved as 6.2 and 4.8% and for PVT-PCM, it is improved as 7.2 and 7.6% for numerically and experimentally respectively.
关键词： PCM,PV/T,Performance,Solar irradiation
更新于2025-09-23 15:23:52
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Introduction of oxygen vacancies into hematite in local reducing atmosphere for solar water oxidation
摘要： Sn Doping and creation of oxygen vacancies have been adopted universally to overcome the poor electric conductivity and unfavorable hole diffusion length of α-Fe2O3 photoanodes. Generally, Sn doping is realized via longitudinal migration of tin element from FTO (fluorine-doped tin oxide) substrates into α-Fe2O3 at high temperature. To introduce oxygen vacancies along with Sn into hematite for further promoting its electric conductivity, we have created a local reducing atmosphere via partial oxidation of graphite while doping hematite with Sn. The donor density of the resultant Fe2O3 photoanode annealed on graphite (G-Fe2O3) at 770 °C for 20 min is increased to ～1.7 times that of the counterpart annealed on SiO2 powders (S-Fe2O3), indicating that the electric conductivity of hematite is improved after introduction of oxygen vacancies. Moreover, oxygen vacancies have been demonstrated to significantly reduce the charge transfer resistance of Sn doped hematite. Consequently, the photocurrent density of G-Fe2O3 is enhanced remarkably (～70%) compared with S-Fe2O3. However, the improvement in photocurrent density due to oxygen vacancies becomes less significant when more Sn is doped into hematite. The strategy for creation of oxygen vacancies reported here can be extended to other photoanodes for better understanding the effect of oxygen vacancies on PEC performance.
关键词： Oxygen vacancies,Sn doping,Solar water oxidation,Hematite
更新于2025-09-23 15:23:52