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- 摘要
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Advancing photovoltaics and thermophotovoltaics with supradegeneracy
摘要： An ongoing challenge facing photovoltaics (PV) and thermophotovoltaics (TPV) is to improve the relatively poor efficiency with which they convert blackbody radiation into electricity. Analysis indicates that a recently proposed phenomenon from statistical mechanics – supradegeneracy – might boost this efficiency and increase system power densities. Supradegeneracy might also expand the palette of attractive PV/TPV materials, allow lower operating temperatures for TPVs, and thereby increase their robustness, reliability, and lifespan. Laboratory tests of the supradegeneracy concept have begun.
关键词： Photovoltaics,Second law of thermodynamics,Thermophotovoltaics,Waste heat,Supradegeneracy
更新于2025-09-12 10:27:22
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Solar Cells and Energy Materials || 2. Solar energy
摘要： The society and technology that human beings have built for themselves are strongly dependent on the consumption of energy. However, earth’s energy resources have been consumed for a long time, and we will have to face energy resource problems and find solutions now if we wish to develop a sustainable human society. If we continue to use fossil fuels at the current rate, they will be completely exhausted within the 21st century. Therefore, there is an urgent need to shift towards the use of renewable energies such as solar energy, nuclear fusion, wind power, biomass, and geothermal energy instead of continuing to use fossil fuels. Renewable energy resources are abundant and have a low impact on the natural environment. On the other hand, they provide low energy density and strongly fluctuate depending on the place and time. Therefore, creating a stable supply of energy is difficult given the current state of technology and the social system we live in, and there are many difficulties in practically using these energy resources.
关键词： solar energy,global warming,renewable energy,thermodynamics,fossil fuels
更新于2025-09-11 14:15:04
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Effects of Gas-Phase Conditions and Particle Size on the Properties of Cu(111)-Supported Zn <sub/>y</sub> O <sub/>x</sub> Particles Revealed by Global Optimisation and Ab Initio Thermodynamics
摘要： The characterisation of the interaction between nano- or sub-nano- particles with a support nowadays increasingly relies on computational modelling by means of the density functional theory calculations. These provide valuable atomic-detail understanding of the structure and energetics of supported clusters, but it is still challenging to find (or design) structural models that are representative of real systems in terms of size, structure, and composition. In this study, we have applied an extensive and systematic approach combining global optimisation based on an evolutionary algorithm with atomistic ab initio thermodynamics for finding stable structures of a relevant material for catalytic methanol synthesis: Cu(111)-supported ZnyOx clusters. We identify the ZnO3 motif as the elementary building block of such clusters, on which we recently have investigated the full catalytic process for methanol synthesis. With the collection of global minima of Cu(111)-supported ZnyOx clusters resulting from this large-scale global optimisation effort, we assess the effect of size, gas-phase conditions, and support interactions on the phase diagrams, reactivity, and structural properties of the ZnyOx particles. We find moderate size-effects that are mostly related to the differences in stable Zn:O ratios of the identified global minima and to the formation of different sites in larger clusters. In contrast, large differences in the oxidation state of the clusters as defined by the gas-phase conditions significantly affect the geometry, electronic structure, and reactivity of the ZnyOx particles. This highlights the importance of thoroughly sampling structures with different stoichiometry and appropriately assessing their stability using a detailed thermodynamics analysis.
关键词： global optimisation,Cu(111)-supported ZnyOx clusters,ab initio thermodynamics,density functional theory,methanol synthesis
更新于2025-09-11 14:15:04
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Density functional theory evaluation of cation-doped bismuth molybdenum oxide photocatalysts for nitrogen fixation
摘要： This study investigates the photocatalytic nitrogen fixation on a cation-doped surface (BixMy)2MoO6 where (M = Fe, La, Yb) in both the orthorhombic and monoclinic configurations using a density functional theory (DFT) approach with experimentally validated model inputs. The proceeding discussion focuses on the Heyrovsky-type reactions for both the associative and dissociative reaction pathway related to nitrogen reduction. Key fundamental insight in the reduction mechanism is discussed that relates the material properties of the substitutional ions to the nitrogen and hydrogen affinities. Physical insight is gathered through interpretation of bound electronic states at the surface. Compositional phases of higher Fe and Yb concentrations resulted in decreased MoeO binding and increased affinity between Mo and the N and H species on the surface. The modulation of the MoeO binding is induced by strain as Yb and Fe are implemented, this, in turn, shifts energy levels and modulates the band gap energy by approximately 0.2 eV. This modification of MoeO bond as substitution occurs is a result of the orbital hybridization of MeO (M = Fe, Yb) that causes a strong orbital interaction that shifts states up toward the Fermi. The optimal composition was predicted to be an orthorhombic configuration of (Bi0.75Fe0.25)2MoO6 with a predicted maximum thermodynamic energy barrier of 1.4 eV. This composition demonstrates effective nitrogen and hydrogen affinity that follows the associative or biological nitrogen fixation pathway.
关键词： Gibbs energy,Thermodynamics,Inorganic,DFT,Nitrogen fixation
更新于2025-09-11 14:15:04
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Measurements, Mechanisms, and Models of Heat Transport || A Macroscopic Model of Blackbody Emissions With Implications
摘要： Measurements of heat transfer in gas, pourable liquids, and nonmetallic solids point to diffusion of radiation being an essential component of heat transport (Chapter 5, Chapter 6 and Chapter 7). Diffusive radiation of heat is a direct outcome of a kinetic theory of gas that incorporates the inelastic nature of collisions (Chapter 5). Long ago, Lommel (1878) associated blackbody (BB) emissions from solids with inelastic losses, and specifically discussed damping of atomic vibrations (Kangro, 1976), but was unable to provide a formula for thermal emissions. His ideas were set aside in the early 1900s. Yet, strong theoretical support for inelasticity exists in the laws of thermodynamics, when these are framed in terms of the macroscopic behavior of light (Chapter 1 and Chapter 5). Fourier’s laws, which describe heat transfer as energy flowing through a medium (Chapter 3), are also consistent with diffusive of radiation explaining conduction in solids.
关键词： blackbody emissions,inelastic collisions,diffusive radiation,heat transfer,thermal emissions,kinetic theory,Fourier’s laws,thermodynamics
更新于2025-09-10 09:29:36
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Simultaneously and Synergistically Harvest Energy from the Sun and Outer Space
摘要： The sun and outer space are the two most important fundamental thermodynamics resources for human beings on Earth. The capability for harvesting solar energy has been of central importance throughout the history of human civilization. Harvesting the coldness of outer space using radiative cooling technology also has a long history and has received renewed interest recently. However, simultaneously and synergistically harvesting energy from these two thermodynamics resources has never been realized. Here we report the first experimental demonstration of such simultaneous energy harvesting using a configuration where a solar absorber that is transparent in mid-infrared is placed above a radiative cooler. The solar absorber is heated to 24°C above the ambient temperature and provides a shading mechanism that enables the radiative cooler to reach 29°C below the ambient temperature. This work points to a new avenue for harvesting of renewable energy resources.
关键词： thermodynamics,renewable energy,energy harvesting,solar energy,radiative cooling
更新于2025-09-10 09:29:36
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Improved design of a photon enhanced thermionic energy converter
摘要： In this work, the model of photon enhanced thermionic energy converter (PETEC) is improved to design a new vacuum thermionic energy converter (VTEC) consisting of a cathode and an anode is established, in which the two electrode materials are made of p-type silicon semiconductor coated negative electron affinity material and boron doped diamond. Formulas for the power output density and efficiency of the VTEC are derived. The electron affinity is optimized to obtain the maximum power output density and efficiency of the VTEC. Making a trade-off between the power output density and efficiency, the parametric optimum design criteria are determined. The results obtained in this work are helpful for developing novel VTECs.
关键词： Electron affinity,Work function,Optimum design,Finite time thermodynamics,Thermionic emission
更新于2025-09-09 09:28:46
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Optimization, kinetics and thermodynamics of photocatalytic degradation of Acid Red 1 by Sm-doped CdS under visible light
摘要： Sm-doped CdS nanoparticles were synthesized through an ultrasound-assisted co-precipitation method and their photocatalytic efficiency was investigated by applying them to photodegradation of Acid Red 1 (AR1) under visible light. The effect of the operational factors on the photocatalytic process was systematically evaluated using response surface methodology. Under the optimal conditions ([AR1]0= 15 mg L-1, [2% Sm-CdS]0= 1 g L-1, pH= 4 and t= 94 min), more than 83% of the AR1 molecules were degraded. The kinetics of the process was well described by the Langmuir-Hinshelwood’s pseudo-first-order model (kapp= 0.0163 min-1). Furthermore, thermodynamics of the process was demonstrated by the activated complex theory of Eyring, which declared that the photocatalytic process is endothermic and nonspontaneous in the temperature range of 25–45°C. In addition, the main products and intermediates of AR1 degradation were determined by the GC-MS technique.
关键词： Sm-doped CdS,Thermodynamics,Visible light photocatalysis,Kinetics,Acid Red 1,RSM
更新于2025-09-09 09:28:46
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Phenomenological approach on electromagnetic waves propagation in normal and diabetic blood, influence of the relative macromolecular structures
摘要： This paper completes the thermodynamic characterization of normal and diabetic blood by the study of the propagation of electromagnetic waves. After a brief introduction on the thermodynamic approach in a biological system, the procedure used is briefly described. The problem of the propagation of electromagnetic waves is faced by deducing an expression of the propagation speed and attenuation of the wave as a function of the frequency. Comparison of results between normal and diabetic blood shows a greater number of permanent dipoles in diabetic blood than in the normal one. Diabetic blood tends to the insolubility because of conformational changes of blood proteins which cannot effectively respond to the stress of the electric field.
关键词： Non-equilibrium thermodynamics,Dielectric relaxation in blood,Blood
更新于2025-09-09 09:28:46
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Complex Formation of Cobalt(II) Octakis(3,5-di-tert-butylphenoxy)phthalocyanine with 2′-(Pyridin-4-yl)-5′-(Pyridin-2-yl)-1′-(Pyridin-2-ylmethyl)-2′,4′-Dihydro-1′H-Pyrrolo[ 3′,4′:1,2][C60-Ih][5,6]fullerene
摘要： The formation of the donor–acceptor complex of cobalt(II) octakis(3,5-di-tert-butylphenoxy)phthalocyanine with 2'-(pyridin-4-yl)-5'-(pyridin-2-yl)-1'-(pyridin-2-ylmethyl)-2',4'-dihydro-1'H-pyrrolo[3',4':1,2][C60-Ih][5,6]fullerene (Py3C60) in toluene was studied by chemical kinetics (thermodynamics) and spectroscopy methods in comparison with a similar system based on 4-picoline (Pic). In both cases, the reaction occurred in one step giving donor–acceptor complexes of 1 : 1 stoichiometry, which were characterized by key spectral (UV-vis, IR, 1H NMR) parameters and thermodynamic equilibrium parameters; in the case of reaction with pyridyl-substituted fullerene, full kinetic description was obtained. The stability constants for (Pic)CoPc(3,5-tBuPhO)8 and (Py3C60)CoPc(3,5-tBuPhO)8 are (1.01 ± 0.16) × 104 L/mol (logK = 4.00, Δ G = –22.84 kJ/mol) and (1.84 ± 0.16) × 105 L/mol (logK = 5.26, Δ G = –30.04 kJ/mol), respectively. The obtained results are relevant for the development of new efficient components for photovoltaic cells based on phthalocyanine–fullerene systems.
关键词： 4-picoline,thermodynamics,phthalocyanine–fullerene complex,kinetics,donor–acceptor complex formation,pyridyl-fullerene,spectral properties,cobalt(II) phthalocyanine
更新于2025-09-09 09:28:46