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A new solar hybrid clean fuel-fired distributed energy system with solar thermochemical conversion
摘要： This paper proposes a new solar hybrid clean fuel-fired distributed energy system to increase the system thermodynamic efficiency and save fossil fuel, in which solar energy is upgraded into high-level chemical energy of syngas (H2 and CO) by integrating the solar-driven methanol decomposition based thermochemical conversion. Solar energy, in the form of chemical energy of the generated syngas, is steadily stored and utilized to drive the distributed energy system to generate power, heat and cooling. The double-axis tracking parabolic trough solar collector is deployed to the proposed system to reduce the cosine loss of solar energy. The incorporation of the solar thermochemistry and double-axis solar concentrator technologies leads to a significant improvement in the solar energy utilization efficiency and the off-design performances under varying solar irradiations. With the integration of solar energy utilization and tri-generation, the proposed system achieves a high net solar-to-electric efficiency, 24.66%, and results in high primary energy ratio, 83.86%, exergy efficiency, 38.81%, and carbon emission saving rate, 51.43%. The proposed system is deployed to an office building to study the operation strategies and annual thermo-economy performances, and competitive off-design performances and economy performances are achieved. The research findings open up a new avenue towards the efficient utilization modes of clean fuel and solar energy.
关键词： Distributed energy system,Solar fuel,Solar thermochemistry,Methanol decomposition,Tracking strategy
更新于2025-09-23 15:23:52
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Carbon Nanotube-Supported Cu <sub/>3</sub> P as High-Efficiency and Low-Cost Cocatalysts for Exceptional Semiconductor-Free Photocatalytic H <sub/>2</sub> Evolution
摘要： Developing an inexpensive and high-efficiency hydrogen-production cocatalyst to replace the noble metal Pt remains a big challenge in the fields of sustainable photocatalytic hydrogen evolution. Herein, we report the exploration of a high-efficient binary noble metal free Cu3P-CNT H2-evolution cocatalyst by direct high-temperature phosphatizing of Cu(OH)2-CNT. Impressively, combining the advantages of noble metal free Cu3P and carbon nanotube (CNT), the binary Cu3P-CNT cocatalysts show high-efficient photocatalytic H2 evolution in Eosin Y(EY)-contained semiconductor-free photocatalytic systems. The maximum visible-light H2-generation rate for promising EY-Cu3P-CNT systems was 17.22 mmolg-1h-1. The highest apparent quantum efficiency (AQE) could reach 10.23% at 500 nm. More importantly, we found that the separation of photogenerated electrons and holes in the Eosin Y, the efficiency of electron transfer from EY to the active edge sites of Cu3P, and the electrocatalytic H2-evolution activity of Cu3P, could be simultaneously boosted via readily adding the conductive CNT, thus achieving the significantly improved photocatalytic H2 evolution. This work provides a simple and facile strategy to design highly efficient semiconductor-free photocatalytic proton-reduction systems using high-activity transition metal phosphides (TMPs) and inexpensive carbon nanomaterials.
关键词： Photocatalytic Hydrogen Evolution,noble metal-free Cu3P Co-catalysts,Solar Fuel,Carbon nanotube (CNT),Dye sensitization
更新于2025-09-23 15:23:52
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3D Yolk@Shell TiO2-x/LDH Architecture: Tailored Structure for Visible Light CO2 Conversion
摘要： CO2 photo-conversion into hydrocarbon solar fuels by engineered semiconductors is considered as a feasible plan to address global energy requirements in times of global warming. In this regard, three dimensional yolk@shell hydrogenated TiO2/Co-Al layered double hydroxide (3D Y@S TiO2-x/LDH) architecture was successfully assembled by sequential solvothermal, hydrogen treatment and hydrothermal preparation steps. This architecture revealed a high efficiency for the photo-reduction of CO2 to solar fuels, without a noble metal co-catalyst. The time dependent experiment indicated that the production of CH3OH was almost selective until 2h (up to 251 μmol/gcat. h.), whereas the CH4 was produced gradually by increasing the time of reaction to 12h (up to 63 μmol/gcat. h.). This significant efficiency can be ascribed to the engineering of 3D Y@S TiO2-x/LDH architecture with considerable CO2 sorption ability in mesoporous yolk@shell structure, and LDH interlayer spaces. Also, oxygen vacancies in TiO2-x could provide excess sites for sorption, activation and conversion of CO2. Furthermore, the generated Ti3+ ions in the Y@S TiO2 structure as well as connecting of structure with LDH plates, can facilitate the charge separation and decrease the band gap of nanoarchitecture to the visible region.
关键词： Solar fuel,Oxygen vacancy,Photocatalysis,CO2 conversion,Nanoarchitectures
更新于2025-09-23 15:22:29
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Photocatalytic solar fuel production and environmental remediation through experimental and DFT based research on CdSe-QDs-coupled P-doped-g-C3N4 composites
摘要： Solar energy harvesting and conversion into useful chemical energy with the aid of semiconductor photocatalysts is a promising technique to solve both energy and environmental issues. This work reports a successful synthesis of CdSe quantum dots (QDs) modified phosphorus doped g-C3N4 (P-CN) for advanced photocatalytic applications. Phosphorus doping and structural coupling with CdSe QDs are shown to significantly extend visible-light response of g-C3N4 up to 700 nm. The optimized sample 4CdSe/P-CN demonstrates enhanced visible-light driven overall water splitting activities for H2 and O2 evolution i.e. 113 and 55.5 μmol.h?1.g?1, respectively, as well as very high photocatalytic CO2 to CH4 conversion efficiency (47 μmol.h?1.g?1). It also exhibit higher activity (78 %) for 2,4-dichlorophenol degradation as compared to pristine CN-sample. Combined photoluminescence, transient/single wavelength photocurrent, photoelectrochemical, and coumarin fluorescence spectroscopy demonstrate that 4CdSe/P-CN nanocomposite exhibit enhanced charge separation efficiency which is responsible for improved visible light catalytic activities. Our work thus provide a new strategy to design low-cost and sustainable photocatalysis with wide visible-light activity for practical overall water splitting and CO2 reduction applications.
关键词： Expending visible-light response,g-C3N4,Phosphorus doping,Solar fuel,CdSe quantum dots
更新于2025-09-23 15:21:01
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Synergy of the catalytic activation on Ni and the CeO <sub/>2</sub> –TiO <sub/>2</sub> /Ce <sub/>2</sub> Ti <sub/>2</sub> O <sub/>7</sub> stoichiometric redox cycle for dramatically enhanced solar fuel production
摘要： Solar thermochemical approaches to CO2 and H2O splitting have emerged as an attractive pathway to solar fuel production. However, efficiently producing solar fuel with high redox kinetics and yields at lower temperature remains a major challenge. In this study, Ni promoted ceria–titanium oxide (CeO2–TiO2) redox catalysts were developed for highly effective thermochemical CO2 and H2O splitting as well as partial oxidation of CH4 at 900 1C. Unprecedented CO and H2 production rates and productivities of about 10–140 and 5–50 times higher than the current state-of-the-art solar thermochemical carbon dioxide splitting and water splitting processes were achieved with simultaneous close to complete CH4 conversions and high selectivities towards syngas. The underlying mechanism for the exceptional reaction performance was investigated by combined experimental characterization and density functional theory (DFT) calculations. It is revealed that the metallic Ni and the Ni/oxide interface manifest catalytic activity for both CH4 activation and CO2 or H2O dissociation, whereas CeO2–TiO2 enhances the lattice oxygen transport via the CeO2–TiO2/Ce2Ti2O7 stoichiometric redox cycle for CH4 partial oxidation and the subsequent CO2 or H2O splitting promoted by catalytically active Ni. Such findings substantiate the significance of the synergy between the reactant activation by catalytic sites and the stoichiometric redox chemistry governing oxygen ion transport, paving the way for designing prospective materials for sustainable solar fuel production.
关键词： thermochemical CO2 splitting,solar fuel production,density functional theory,Ni promoted ceria–titanium oxide,thermochemical H2O splitting,methane partial oxidation,redox catalysts
更新于2025-09-19 17:15:36
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Experimental framework for evaluation of the thermodynamic and kinetic parameters of metal-oxides for solar thermochemical fuel production
摘要： The two-step metal oxide redox cycle is a promising and thermodynamically attractive means of solar fuel production. In this work, we describe the development of a high-temperature tubular reactor in which the fundamental thermodynamic and kinetic behaviour of thermochemical materials can be readily assessed. This reactor system is capable of operating at temperatures up to 1873 K, total pressures ranging from vacuum to ambient, and oxygen partial pressures (pO2) as low as 10-29 atm. Compared to off-the-shelf systems like thermogravimetric analyzers (TGA) or indirect conductivity-based measurement systems, this system has three inherent benefits: (1) the flexibility to control the sample morphology (e.g. powder, packed bed, reticulated porous ceramic, or pellet), (2) the potential for a well-developed and characterized flow, and (3) the ability to readily customize the system on demand (e.g. easy integration with a steam generator to control and operate at very low pO2). The reactor system and experimental methods were validated by performing isothermal relaxation experiments with undoped ceria, wherein the sample environment was rapidly altered by stepwise changes in the delivered H2O vapor concentration, and comparing measured oxygen nonstoichiometries with accepted data available in the literature. Data was measured at temperatures from 1173-1473 K and pO2 from 4.54×10-18-1.02×10-9 atm. The measured equilibrium data displayed strong agreement with the literature and the expected trends were preserved. Kinetic data was extracted by first transforming reactant concentrations measured downstream of the reaction zone using a tanks-in-series mixing model to account for gas dispersion. Next, a mechanistic kinetic model distinguishing surface and bulk species concentrations was fit to the data to extract pertinent thermodynamic and kinetic parameters. The model assumed a two-step reaction mechanism mediated by the formation of an intermediate hydroxyl species on the surface. Activation energies and defect formation enthalpies and entropies for the forward and reverse reactions were found to be in good agreement with previous modelling efforts, providing further validation of the use of this system to explore thermodynamic and kinetic behaviour of emerging thermochemical materials.
关键词： thermodynamic and kinetic parameters,undoped ceria,solar fuel production,metal oxide redox cycle,high-temperature tubular reactor
更新于2025-09-09 09:28:46
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Non-Stoichiometric Redox Active Perovskite Materials for Solar Thermochemical Fuel Production: A Review
摘要： Due to the requirement to develop carbon-free energy, solar energy conversion into chemical energy carriers is a promising solution. Thermochemical fuel production cycles are particularly interesting because they can convert carbon dioxide or water into CO or H2 with concentrated solar energy as a high-temperature process heat source. This process further valorizes and upgrades carbon dioxide into valuable and storable fuels. Development of redox active catalysts is the key challenge for the success of thermochemical cycles for solar-driven H2O and CO2 splitting. Ultimately, the achievement of economically viable solar fuel production relies on increasing the attainable solar-to-fuel energy conversion ef?ciency. This necessitates the discovery of novel redox-active and thermally-stable materials able to split H2O and CO2 with both high-fuel productivities and chemical conversion rates. Perovskites have recently emerged as promising reactive materials for this application as they feature high non-stoichiometric oxygen exchange capacities and diffusion rates while maintaining their crystallographic structure during cycling over a wide range of operating conditions and reduction extents. This paper provides an overview of the best performing perovskite formulations considered in recent studies, with special focus on their non-stoichiometry extent, their ability to produce solar fuel with high yield and performance stability, and the different methods developed to study the reaction kinetics.
关键词： solar fuel,concentrating solar technologies,non-stoichiometric materials,perovskites,CO2/H2O splitting,hydrogen,thermochemical cycles,oxygen vacancies
更新于2025-09-04 15:30:14