查看更多>>摘要：Thermal energy storage is crucial in the context of achieving carbon neutrality.Phase change latent heat stands out among various thermal storage methods due to the high energy density of phase change materials(PCMs).PCMs possess unique characteristics such as tunable thermal storage or/and release processes,constant phase-transition temperatures,and changes in physical state.However,solid-liquid PCMs cannot be directly utilized due to the liquid leakage in their melted state.The encapsulation of PCM microcapsules(PCMMs)is essential for overcoming limitations and optimizing functionalities of the PCMs.Encapsulation strategies play a key role in considering factors like morphology,structure,physicochemical properties,and specific applications.Further-more,PCMMs can expand their potential applications by incorporating functional nano-materials within their shells or introducing specific components into their cores during the synthesis process.This review examines various encapsulation strategies for PCMMs,including physical,physicochemical,and chemical methods.Various applications of PCMMs are summarized and analyzed with regards to the characteristics of PCMs in thermal storage,temperature control,and state transformation.Furthermore,the reinforcement strategies or/and design considerations of PCMMs are crucial for meeting specific requirements,such as conventional latent heat storage,thermal protection,and thermal-triggered intelligent materials.Finally,it discusses current challenges,proposed solutions,and future research directions in the field of PCMMs,particularly Janus particle modified PCMMs.
查看更多>>摘要：Achieving subwavelength optical focusing is of great importance in nanophotonics.However,achieving focusing with both a small focal spot size and a large focal length remains elusive so far.Here,a large focal length planar focusing device is presented,utilizing highly oriented Dyakonov polaritons in hyperbolic metamaterial with periodic silver rings as the excitation source.Experimental results show that by controlling the size of the exci-tation sources,the focal length can reach 6λ0(where λ0 is the illumination wavelength),and the focal spot size can be reduced to λ0/10.This method provides new prospects for planar polariton optical applications.
查看更多>>摘要：Energy transition towards net-zero society calls for utilization of renewable power to drive CO2 conversion in an efficient electrochemical way.The development of a commercial CO2 electrolyzer with positive tech-eco effect calls for active and durable electrocatalysts.High-loading gold on carbon(Au/C)with reduced particle size is the prerequisite for the highly-selective and highly energy-efficient CO production in such a CO2 electrolyzer,but a scalable synthetic method is missing.With combined control of ligand,substrate and pH value,Au/C catalysts with particle size within 5 nm and metal loading of 40 wt％and 60 wt％are synthesized on low and high surface-area carbon,respectively.We also provide a thorough investigation of the effect of the ligand type,surface charge of gold nanoparticles(Au NPs)and surface area of carbon substrate on the loading limit of Au/C.
查看更多>>摘要：Nowadays,an increasing number of scientists attach more importance to zero thermal expansion(ZTE)materials which are uncommon yet highly significant in the field of solid-state materials.The key to explore new ZTE compounds is to understand the mechanism,while it remains unclear.Here,we utilize density functional theory calculations to elucidate the mechanisms of NiPt(CN)6.A joint study of bond nature,atomic mean-square displacements,phonon dispersion curves,Grüneisen parameters,and phonon vibrations to systematically analyze the ZTE mechanisms.The results suggest that the transverse vibrations of the-C≡N-groups are instrumental,particularly due to the involvement of the N atoms and the nature of the Ni-N and Pt-C bonds.Phonon modes with negative Grüneisen parameters at low frequencies play the mainly role to balance the positive thermal expansion from others frequency zone modes to obtain the ZTE behavior.This work demonstrates that NiPt(CN)6 maintains substantial similarities with its trivalent-trivalent analogues,further enhancing our comprehension of NTE properties within open-framework structure.
查看更多>>摘要：Surface poisoning typically leads to the severe capacity degradation and poses a significant challenge to the durability of hydrogen storage materials.In this study,we report a novel approach to enhance the air-poisoning resistance of vanadium-based alloys by introducing of the air-tolerant hydride.Through the addition of 1 at％Si,a small amount of Ti5Si3 is induced in V75Ti11Cr13Fe1,which turns into Ti5Si3H0.9 during the hydrogen sorption cycles.Ti5Si3H0.9 shows high resistance against air,which could serve as the hydrogen-entry window for the bulk.As a result,the(V75Ti11Cr13Fe1)ggSi1 alloy maintains approximately 85％of the hydrogen storage capacity after 10 cycles in H2+250 ppm air,in contrast to the near-complete loss of hydrogen sorption activity in Si-free alloy under the same condition.
查看更多>>摘要：Pt-based catalysts are often used in a proton exchange membrane fuel cell due to their high activities to oxygen reduction and hydrogen oxidation reaction.However,these catalysts are easily poisoned by CO,resulting in a significant reduction of fuel cell performance.The use of CO-tolerant catalysts can effectively solve this problem.The CO poisoning mechanism and anti-poisoning strategies were briefly discussed in this article.It mainly focused on the research progress on CO-tolerant catalysts in three aspects:Pt alloy catalysts,metal oxide composite catalysts,and blocking layer covered catalysts.The advantages and limitations of various catalysts in recent years were also discussed.Creating a porous blocking layer covered on the surface of the catalyst can effectively enhance the CO-tolerance of the catalysts which could be a promising approach for developing anti-poison cat-alysts other than CO-tolerance.Finally,the prospects for future development of CO-tolerant fuel cell catalysts were described.
查看更多>>摘要：Earth-abundant Fe oxide-based catalysts,renowned for their broad-spectrum light absorption,hold promise for driving the photothermal RWGS reaction—a promising strategy for converting CO2 emissions into valuable carbonaceous feedstocks.However,traditional Fe oxide-based catalysts exhibit limited activity due to their constrained H2 dissociation and CO2 activation capabilities,especially at lower temperatures.This study in-troduces Co,Ni,and Cu-doped Ce0.7Fe0.3O2 solid-solution catalysts.Incorporation of Fe into CeO2 enhances CO2 dissociation while preserving extensive light adsorption up to 2500 nm.Notably,Co doping enhances H2 dissociation and promotes CO2 activation.Subsequent investigations reveal that a catalyst doped with 5 mol％Co exhibits the highest photothermal catalytic activity,attaining a～50％CO2 conversion under 300 W Xe-lamp irradiation with excellent selectivity and stability over 10 reaction cycles spanning 10 h.These results under-score the potential of designing CeO2-based solid solution catalysts with synergistic metal dopants for efficient and selective CO2 conversion under moderate conditions.
查看更多>>摘要：Due to serious harm of triethylamine(TEA)to environmental safety and human health,it is significant to syn-thesize gas-sensitive materials with high performance for TEA detection.However,it is still a challenge to achieve high-sensitivity detection of TEA at low temperature for a sensor synthesized through an economical and efficient method.In this work,hollow-structured SnO2(HS-SnO2)nanospheres have been fabricated by a facile,low-cost hydrothermal method in one step,which exhibit superior TEA-sensing properties,including not only ultrahigh response(127.75)for 100 ppm TEA,good selectivity,but also fast response and recovery time(17/28 s),low detection threshold(1 ppm)and robust stability at a relatively low optimum operational temperature of 225 ℃.The excellent gas-sensitizing performances are ascribed to porous hollow structures with rich oxygen vacancies that provide abundant active sites for raising O2 adsorption and reaction of TEA and oxygen species.This work offers an effective and economical strategy for fabricating high-performance TEA sensors for industrial applications.
查看更多>>摘要：In this paper,the microstructure evolution and properties of squeeze-cast Al-8Si-1.5Cu-1Ni-0.5Mg-0.5Mn-0.2V-0.2Ti-0.2Zr alloy(hereafter,Al-Si-Cu-Ni alloy for short)were investigated under various solution processes,evaluating the mechanical properties at room and elevated temperatures for both as-cast and T6-treated states.The results showed that following the optimal two-stage solution(i.e.,solution at 510 ℃ for 6 h+solution at 530 ℃ for 8 h)and subsequent aging at 190 ℃ for 10 h,referred to as the S530-T6 treatment,the Al-Si-Cu-Ni alloy exhibited excellent room/high temperature performance.The ultimate tensile strength(UTS),yield strength(YS)and elongation of the alloy at room temperature were 410 MPa,368 MPa and 1.5％,and the UTS,YS and elongation of alloy at 300 ℃ were 177 MPa,170 MPa and 6％,respectively.The increase in strength at room temperature is mainly attributed to the spheroidization of eutectic silicon and the precipitate strengthening aroused from uniformly dispersed nano-sized Q-Al4Cu2Mg8Si7,σ-Al5Cu6Mg2 and θ'-Al2Cu phases,while the in-crease in strength at high temperature is due to the formation of heat-resistant Ni-rich phases and the improvement of the micromorphology of high melting point intermetallic compounds.
查看更多>>摘要：Spent galvanizing acid solution contains high concentrations of zinc salts,ferrous salts,and residual acids,exhibiting extremely high value-added recovery potential.However,achieving the efficient extraction and sep-aration of Zn over Fe becomes particularly challenging under elevated Zn ion concentration.Here,the key extraction parameters,such as modifier ratio,Cyanex 923 concentration and ratio of organic phase to aqueous phase(O/A),are investigated.The stripping and regeneration of extractant,extraction mechanism,as well as high-value recovery of Zn and Fe resources are also comprehensively expounded.After the two-stage extraction,the extraction efficiency of Zn and Fe is 98.92％and 2.09％,respectively.Moreover,the stripping efficiency of Zn reaches 92.3％with O/A ratio of 1:2,using oxalic acid as stripping agent.The predominant extracted species is confirmed to be ZnCl3-,resulting in the formation of HZnCl3·R3PO complex.More importantly,the regenerated extractant can be recycled back into the extraction process,and the reproduced HC1,high-value recovered ZnO and Fe2O3 can be used for different industrial fields.These findings lay a solid foundation for the efficient sep-aration and comprehensive recovery of high-concentration spent galvanizing acid solution.
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