Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring ...Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production.展开更多
Hydrogen(H2)production is a latent feasibility of renewable clean energy.The industrial H2 production is obtained from reforming of natural gas,which consumes a large amount of nonrenewable energy and simultaneously p...Hydrogen(H2)production is a latent feasibility of renewable clean energy.The industrial H2 production is obtained from reforming of natural gas,which consumes a large amount of nonrenewable energy and simultaneously produces greenhouse gas carbon dioxide.Electrochemical water splitting is a promising approach for the H2 production,which is sustainable and pollution-free.Therefore,developing efficient and economic technologies for electrochemical water splitting has been an important goal for researchers around the world.The utilization of green energy systems to reduce overall energy consumption is more important for H2 production.Harvesting and converting energy from the environment by different green energy systems for water splitting can efficiently decrease the external power consumption.A variety of green energy systems for efficient producing H2,such as two-electrode electrolysis of water,water splitting driven by photoelectrode devices,solar cells,thermoelectric devices,triboelectric nanogenerator,pyroelectric device or electrochemical water-gas shift device,have been developed recently.In this review,some notable progress made in the different green energy cells for water splitting is discussed in detail.We hoped this review can guide people to pay more attention to the development of green energy system to generate pollution-free H2 energy,which will realize the whole process of H2 production with low cost,pollution-free and energy sustainability conversion.展开更多
Sunlight is the most abundant renewable energy resource,providing the earth with enough power that is capable of taking care of all of humanity’s desires-a hundred times over.However,as it is at times diffuse and int...Sunlight is the most abundant renewable energy resource,providing the earth with enough power that is capable of taking care of all of humanity’s desires-a hundred times over.However,as it is at times diffuse and intermittent,it raises issues concerning how best to reap this energy and store it for times when the Sun is not shining.With increasing population in the world and modern economic development,there will be an additional increase in energy demand.Devices that use daylight to separate water into individual chemical elements may well be the answer to this issue,as water splitting produces an ideal fuel.If such devices that generate fuel were to become widely adopted,they must be low in cost,both for supplying and operation.Therefore,it is essential to research for cheap technologies for water ripping.This review summarizes the progress made toward such development,the open challenges existing,and the approaches undertaken to generate carbon-free energy through water splitting.展开更多
As a secondary energy with great commercialization potential,hydrogen energy has been widely studied due to the high calorific value,clean combustion products and various reduction methods.At present,the blueprint of ...As a secondary energy with great commercialization potential,hydrogen energy has been widely studied due to the high calorific value,clean combustion products and various reduction methods.At present,the blueprint of hydrogen energy economy in the world is gradually taking shape.Compared with the traditional high-energy consuming methane steam reforming hydrogen production method,the electrocatalytic water splitting hydrogen production stands out among other process of hydrogen production owning to the mild reaction conditions,high-purity hydrogen generation and sustainable production process.Basing on current technical economy situation,the highly electric power cost limits the further promotion of electrocatalytic water splitting hydrogen production process.Consequently,the rational design and development of low overpotential and high stability electrocatalytic water splitting catalysts are critical toward the realization of low-cost hydrogen production technology.In this review,we summarize the existing hydrogen production methods,elaborate the reaction mechanism of the electrocatalytic water splitting reaction under acidic and alkaline conditions and the recent progress of the respective catalysts for the two half-reactions.The structure-activity relationship of the catalyst was deep-going discussed,together with the prospects of electrocatalytic water splitting and the current challenges,aiming at provide insights for electrocatalytic water splitting catalyst development and its industrial applications.展开更多
The main objective of this study was to investigate the impact of effective mass splitting on heavy-ion-collision observables.We first analyzed correlations between different nuclear matter parameters obtained from 11...The main objective of this study was to investigate the impact of effective mass splitting on heavy-ion-collision observables.We first analyzed correlations between different nuclear matter parameters obtained from 119 effective Skyrme interaction sets.The values of the correlation coefficients illustrate that the magnitude of effective mass splitting is crucial for tight constraints on the symmetry energy via heavy-ion collisions.The^(86)Kr+^(208)Pb system at beam energies ranging from 25 to 200A MeV was simulated within the framework of the improved quantum molecular dynamics model(ImQMD-Sky).Our calculations show that the slopes of the spectra of ln[Y(n)/Y(p)]and ln[Y(t)/Y(^(3)He)],which are the logarithms of the neutron to proton and triton to helium-3 yield ratios,are directly related to effective mass splitting and can be used to probe the effective mass splitting.展开更多
Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and storage.By utilizing semiconductor photoelectrodes,PEC devices can harness solar energy...Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and storage.By utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added chemicals.However,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical implementation.Recently,significant research has been conducted to improve the overall conversion efficiency of PEC devices.One particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy conversion.This review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) reduction.The main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/hydroxides.Meanwhile,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based cocatalysts.In addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with cocatalysts.Finally,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.展开更多
A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed.Based on the new code,four commonly used parameter sets,SLy4,SkI2,SkM*and Gs are adopted in the ...A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed.Based on the new code,four commonly used parameter sets,SLy4,SkI2,SkM*and Gs are adopted in the improved quantum molecular dynamics model and the isospin sensitive observables,namely isospin transport ratios,single and double ratios of the yields of neutrons and protons are investigated.The isospin transport ratios are strongly sensitive to the slope of symmetry energy,and are not very sensitive to the nucleon effective mass splitting.On the other hand,the high energy neutrons and protons yields ratios from reactions at different incident energies provide a good observable to the momentum dependence of nucleon effective mass splitting.By comparing our calculations with the data,we find that the constrained L value(the slope of density dependence of symmetry energy) is about ~46 MeV when the Skyrme type interaction is considered in transport models,and the isospin diffusion data prefer to mn*>mp*,but it is not a strong constraint with deep χ2minimum.展开更多
As the demands of massive connections and vast coverage rapidly grow in the next wireless communication networks, rate splitting multiple access(RSMA) is considered to be the new promising access scheme since it can p...As the demands of massive connections and vast coverage rapidly grow in the next wireless communication networks, rate splitting multiple access(RSMA) is considered to be the new promising access scheme since it can provide higher efficiency with limited spectrum resources. In this paper, combining spectrum splitting with rate splitting, we propose to allocate resources with traffic offloading in hybrid satellite terrestrial networks. A novel deep reinforcement learning method is adopted to solve this challenging non-convex problem. However, the neverending learning process could prohibit its practical implementation. Therefore, we introduce the switch mechanism to avoid unnecessary learning. Additionally, the QoS constraint in the scheme can rule out unsuccessful transmission. The simulation results validates the energy efficiency performance and the convergence speed of the proposed algorithm.展开更多
Based on the combination of Racah's group-theoretical consideration with Slater's wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3+ ion. Thus, the Stark energ...Based on the combination of Racah's group-theoretical consideration with Slater's wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3+ ion. Thus, the Stark energy-levels of Pr3+ ions doped separately in LiYF4 and LiBiF4 crystals are calculated, and our calculations imply that the complete energy matrix method can be used as an effective tool to calculate the energy-levels of the systems doped by rare earth ions. Besides, the influence of Pr3+ on energy-level splitting is investigated, and the similarities and the differences between the two doped crystals are demonstrated in detail by comparing their several pairs of curves and crystal field strength quantities. We see that the energy splitting patterns are similar and the crystal field interaction of LiYF4:Pr3+ is stronger than that of LiBiF4:Pr3+.展开更多
The inter-relation between zero-field splitting (ZFS) parameters and local lattice structures of the (CrSe4)6 clusters in ZnSe semiconductors has been established by using the complete diagonalization (of the ene...The inter-relation between zero-field splitting (ZFS) parameters and local lattice structures of the (CrSe4)6 clusters in ZnSe semiconductors has been established by using the complete diagonalization (of the energy matrix) method. On the basis of this, the local lattice distortions, the ZFS parameters D, a, F and the optical spectrum for Cr2+ ions doped into ZnSe are theoretically investigated, and the contributions of the spin singlets have been taken into account. The calculated ZFS parameters are in good agreement with the experimental values. From our calculations, the tetragonal distortion parameters AR = 0.091A and Aθ = 4.28° of Cr2+ in ZnSe are acquired, and the results suggest that there exists a tetragonal expansion distortion for the local lattice structure of (CrSe4)6- clusters in ZnSe crystals. The influence of the spin singlets on ZFS parameters is also discussed, indicating that the contributions to ZFS parameters a and F cannot be ignored.展开更多
Using carbon felt,polytetrafluoroethylene latex and powder catalyst to assembly a light energy conversion device,the photocatalytic activity of catalyst 2.0%WO3-TiO2(2%WO3 compounding TiO2) with oxygen vacancies was s...Using carbon felt,polytetrafluoroethylene latex and powder catalyst to assembly a light energy conversion device,the photocatalytic activity of catalyst 2.0%WO3-TiO2(2%WO3 compounding TiO2) with oxygen vacancies was studied through the water splitting for O2 evolution,using a high pressure mercury lamp as the light source and Fe 3+ as the electron acceptor in two different devices:an ordinary photolysis device with catalyst powder suspending through a magnetic stirrer and a self-assembly light energy conversion device.The results show that after 12 h irradiation,the photocatalytic activity of 2.0%WO3-TiO2 with oxygen vacancies in the self-assembly light energy conversion device is higher than that of the ordinary photolysis device,and the amount of oxygen evolution is about 12 and 9 mmol/L respectively in these two devices.After 12 h,the rates of O2 evolution are slow in each device and the photocatalyst almost loses the photoactivity in the ordinary photolysis device.So,compared with the ordinary photocatalytic device,the rate of oxygen evolution and the life time of the catalyst are improved in the self-assembly light energy conversion device.展开更多
Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy).By means of improved li...Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy).By means of improved ligand-field theory,the R line,t_2^(32)T_1 and t_2^(32)T_2 lines,t_2~2(~3T_1)e^4T_2,t_2~2(~3T_1)e^4T_1 and t_2e^2(~4A_2)~4T_1 bands,g factors of t_2~3 ~4A_2 and t_2^(32)E,four strain-induced level-splittings and R-line thermal shift of MgO:V^(2+) have been calculated.The results are in very good agreement with the experimental data.It is found that for MgO:V^(2+),the contributions due to electron- phonon interaction (EPI) come from the first-order term;the contributions from the second-order and higher terms are insignificant.In thermal shift of R line of MgO:V^(2+),the temperature-dependent contribution due to EPI is dominant. The results obtained in this work may be used in theoretical calculations of other effects of EPI.展开更多
Developing earth-abundant-electrocatalysts for hydrogen evolution reaction is one of the promising ways to achieve efficient water-splitting for hydrogen production(a clean chemical fuel).This paper reviews the activi...Developing earth-abundant-electrocatalysts for hydrogen evolution reaction is one of the promising ways to achieve efficient water-splitting for hydrogen production(a clean chemical fuel).This paper reviews the activity,stability and durability for hydrogen evolution reaction in alkaline medium of different types of recently reported potential electrocatalysts such as Ni,Co,NiCo,Fe,Cu,W,Mo,Se,Mn.Zn,V,and metal free based earth-abundant-electrocatalysts.Further,this paper reviews the strategies used to achieve the remarkably low overpotential(including r/i0:<35mV),high long term stability(including^:100 h)and high durability(including>5000 cycles)of potential earth-abundant-electrocatalysts for hydrogen evolution reaction in alkaline medium and those are better or well comparable with the state-of-the-art,noble,Pt/C electrocatalyst.Finally,this paper summarizes the efficient strategies such as preparing porous structured materials,preparing nanostructured materials with superaerophobic surface,preparing nanostructured materials,preparing carbon composites/integrating electrocatalysts with carbon,preparing amorphous materials,preparing materials w让h oxygen vacancies/defects,preparing metal chalcogenides,preparing bimetallic/multi-metallic materials,doping metals or heteroatoms,preparing electrocatalysts with core-shell structure,decorating electrocatalysts with amines,preparing homojunction/heterojunction structured materials,preparing hollow structured materials,and preparing boronrich surface to enhance the activity,stability,and durability for HER.展开更多
Tuning the electronic structure of the electrocatalysts for oxygen evolution reaction(OER)is a promising way to achieve efficient alkaline water splitting for clean energy production(H2).At first,this paper introduces...Tuning the electronic structure of the electrocatalysts for oxygen evolution reaction(OER)is a promising way to achieve efficient alkaline water splitting for clean energy production(H2).At first,this paper introduces the significance of the tuning of electronic structure,where modifying the electronic structure of the electrocatalysts could generate active sites having optimal adsorption energy with OER intermediates,and that could diminish the energy barrier for OER,and that could improve the activity for OER.Later,this paper reviews the tuning of electronic structure along with catalytic performances,synthetic methodologies,chemical properties,and DFT calculations on various nanostructured earth-abundant electrocatalysts for OER in alkaline environment.Further,this review discusses the tuning of the electronic structure of the several nanostructured earth-abundant electrocatalysts including oxide,(oxy)hydroxide,layered double hydroxide,alloy,metal phosphide/phosphate,nitride,sulfide,selenide,carbon containing materials,MOF,core-shell/hetero/hollow structured materials,and materials with vacancies/defects for OER in alkaline environment(including activity:overpotential(η)of ≤200 mV at10 m A cm^(-2);stability:≥100 h;durability:≥5000 cycles).Then,this review discusses the robust stability of the electrocatalysts for OER towards practical application.Moreover,this review discusses the in situ formation of thin layer on the catalyst surface during OER.In addition,this review discusses the influence of the adsorption energy of the OER intermediates on OER performance of the catalysts.Finally,this review summarizes the various promising strategies for tuning the electronic structure of the electrocatalysts to achieve enhanced performance for OER in alkaline environment.展开更多
Photoelectrochemical(PEC)fuel generation from water splitting and CO_(2)reduction(CO_(2)R)utilizing solar energy holds immense potential to solve the current energy and environmental issues.In the past decades,numerou...Photoelectrochemical(PEC)fuel generation from water splitting and CO_(2)reduction(CO_(2)R)utilizing solar energy holds immense potential to solve the current energy and environmental issues.In the past decades,numerous studies have been devoted to this fast-growing research field,and it is essential to develop efficient photoelectrodes with earth-abundant materials for the practical application of PEC systems.A thorough review of earth-abundant materials and associated devices for PEC fuel generation is beneficial to uncover the inherent obstacles and pave the way for future research.Herein,we summarize the recent progress of earth-abundant light-absorbers and cocatalysts in the PEC systems.The unbiased configurations and scaling-up strategies of PEC devices using earth-abundant materials are examined.A comparison between PEC water splitting and CO_(2)R is carried out to promote better understanding of the design principles for practical materials and devices.Last,the prospects on advanced materials,underlying mechanisms,and reaction systems of PEC water splitting and CO_(2)R are proposed.展开更多
Experiments of CO_2 splitting by dielectric barrier discharge(DBD) plasma were carried out, and the influence of CO_2 flow rate, plasma power, discharge voltage, discharge frequency on CO_2 conversion and process en...Experiments of CO_2 splitting by dielectric barrier discharge(DBD) plasma were carried out, and the influence of CO_2 flow rate, plasma power, discharge voltage, discharge frequency on CO_2 conversion and process energy efficiency were investigated. It was shown that the absolute quantity of CO_2 decomposed was only proportional to the amount of conductive electrons across the discharge gap,and the electron amount was proportional to the discharge power; the energy efficiency of CO_2 conversion was almost a constant at a lower level, which was limited by CO_2 inherent discharge character that determined a constant gap electric field strength. This was the main reason why CO_2 conversion rate decreased as the CO_2 flow rate increase and process energy efficiency was decreased a little as applied frequency increased. Therefore, one can improve the CO_2 conversion by less feed flow rate or larger discharge power in DBD plasma, but the energy efficiency is difficult to improve.展开更多
Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the iso...Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the isospin emission in heavy-ion collisions is investigated thoroughly.It is found that the yield ratios of energetic neutrons to protons squeezed out during the compression stage of two colliding nuclides are sensitive to the isospin splitting.The elliptic flows of free nucleons are also to be promising observables for extracting the nucleon effective mass splitting.Further experimental measurements are being expected,in particular at the CSR-CEE platform in Lanzhou.Several observables are proposed for constraining the density dependence of symmetry energy,such as the transverse flow difference of neutrons and protons,double ratios of n/p and π-/π+,excitation functions of π-/π+ and K0/K+.展开更多
The sustainable production of green hydrogen via water electrolysis necessitates cost-effective electrocatalysts.By following the circular economy principle,the utilization of waste-derived catalysts significantly pro...The sustainable production of green hydrogen via water electrolysis necessitates cost-effective electrocatalysts.By following the circular economy principle,the utilization of waste-derived catalysts significantly promotes the sustainable development of green hydrogen energy.Currently,diverse waste-derived catalysts have exhibited excellent catalytic performance toward hydrogen evolution reaction(HER),oxygen evolution reaction(OER),and overall water electrolysis(OWE).Herein,we systematically examine recent achievements in waste-derived electrocatalysts for water electrolysis.The general principles of water electrolysis and design principles of efficient electrocatalysts are discussed,followed by the illustration of current strategies for transforming wastes into electrocatalysts.Then,applications of waste-derived catalysts(i.e.,carbon-based catalysts,transitional metal-based catalysts,and carbon-based heterostructure catalysts)in HER,OER,and OWE are reviewed successively.An emphasis is put on correlating the catalysts’structure-performance relationship.Also,challenges and research directions in this booming field are finally highlighted.This review would provide useful insights into the design,synthesis,and applications of waste-derived electrocatalysts,and thus accelerate the development of the circular economy-driven green hydrogen energy scheme.展开更多
Photoelectrochemical water splitting(PEC-WS)is a promising technique for transforming solar energy into storable and environmentally friendly chemical energy.Designing semiconductor photoelectrodes with high light abs...Photoelectrochemical water splitting(PEC-WS)is a promising technique for transforming solar energy into storable and environmentally friendly chemical energy.Designing semiconductor photoelectrodes with high light absorption capability,rapid e-/h+separation and transfer,and sufficient chemical stability is vital for developing an efficient PEC-WS system.Metal chalcogenides(MCs)have emerged as promising candidates for light absorbers because of their unique electrical and optical characteristics.In this review,we present recent developments in hydrogen generation via PEC-WS using MC-based photoelectrodes.First,we present a simple illustration of PEC-WS fundamentals.Second,the current performance of various metal(mono-,di-,and tri-)chalcogenide/semiconductor photoelectrodes in PEC-WS is summarized.Then,the charge transfer mechanism at the MC/semiconductor interface and the PEC-WS mechanism is thoroughly explained.Finally,we discuss future research perspectives toward developing efficient and stable MC/semiconductor photoelectrodes.展开更多
基金financial support from The University of Manchester to cover his PhD tuition fees for him to carry out this workChina National High-end Foreign Experts Recruitment Plan Project (G2023018001L) for partially supporting the work。
文摘Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production.
基金supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410)the National Natural Science Foundation of China(51972147)。
文摘Hydrogen(H2)production is a latent feasibility of renewable clean energy.The industrial H2 production is obtained from reforming of natural gas,which consumes a large amount of nonrenewable energy and simultaneously produces greenhouse gas carbon dioxide.Electrochemical water splitting is a promising approach for the H2 production,which is sustainable and pollution-free.Therefore,developing efficient and economic technologies for electrochemical water splitting has been an important goal for researchers around the world.The utilization of green energy systems to reduce overall energy consumption is more important for H2 production.Harvesting and converting energy from the environment by different green energy systems for water splitting can efficiently decrease the external power consumption.A variety of green energy systems for efficient producing H2,such as two-electrode electrolysis of water,water splitting driven by photoelectrode devices,solar cells,thermoelectric devices,triboelectric nanogenerator,pyroelectric device or electrochemical water-gas shift device,have been developed recently.In this review,some notable progress made in the different green energy cells for water splitting is discussed in detail.We hoped this review can guide people to pay more attention to the development of green energy system to generate pollution-free H2 energy,which will realize the whole process of H2 production with low cost,pollution-free and energy sustainability conversion.
文摘Sunlight is the most abundant renewable energy resource,providing the earth with enough power that is capable of taking care of all of humanity’s desires-a hundred times over.However,as it is at times diffuse and intermittent,it raises issues concerning how best to reap this energy and store it for times when the Sun is not shining.With increasing population in the world and modern economic development,there will be an additional increase in energy demand.Devices that use daylight to separate water into individual chemical elements may well be the answer to this issue,as water splitting produces an ideal fuel.If such devices that generate fuel were to become widely adopted,they must be low in cost,both for supplying and operation.Therefore,it is essential to research for cheap technologies for water ripping.This review summarizes the progress made toward such development,the open challenges existing,and the approaches undertaken to generate carbon-free energy through water splitting.
基金financial support from the National Nature Science Foundation of China(22122113)National Key Research&Development Program of China(2021YFB4000405)。
文摘As a secondary energy with great commercialization potential,hydrogen energy has been widely studied due to the high calorific value,clean combustion products and various reduction methods.At present,the blueprint of hydrogen energy economy in the world is gradually taking shape.Compared with the traditional high-energy consuming methane steam reforming hydrogen production method,the electrocatalytic water splitting hydrogen production stands out among other process of hydrogen production owning to the mild reaction conditions,high-purity hydrogen generation and sustainable production process.Basing on current technical economy situation,the highly electric power cost limits the further promotion of electrocatalytic water splitting hydrogen production process.Consequently,the rational design and development of low overpotential and high stability electrocatalytic water splitting catalysts are critical toward the realization of low-cost hydrogen production technology.In this review,we summarize the existing hydrogen production methods,elaborate the reaction mechanism of the electrocatalytic water splitting reaction under acidic and alkaline conditions and the recent progress of the respective catalysts for the two half-reactions.The structure-activity relationship of the catalyst was deep-going discussed,together with the prospects of electrocatalytic water splitting and the current challenges,aiming at provide insights for electrocatalytic water splitting catalyst development and its industrial applications.
基金supported by the National Natural Science Foundation of China(Nos.12275359,11875323,11961141003,U2032145,11890712)the National Key R&D Program of China(No.2018YFA0404404)+1 种基金the Continuous Basic Scientific Research Project(Nos.WDJC-2019-13 and BJ20002501)funding from the China Institute of Atomic Energy(No.YZ222407001301).
文摘The main objective of this study was to investigate the impact of effective mass splitting on heavy-ion-collision observables.We first analyzed correlations between different nuclear matter parameters obtained from 119 effective Skyrme interaction sets.The values of the correlation coefficients illustrate that the magnitude of effective mass splitting is crucial for tight constraints on the symmetry energy via heavy-ion collisions.The^(86)Kr+^(208)Pb system at beam energies ranging from 25 to 200A MeV was simulated within the framework of the improved quantum molecular dynamics model(ImQMD-Sky).Our calculations show that the slopes of the spectra of ln[Y(n)/Y(p)]and ln[Y(t)/Y(^(3)He)],which are the logarithms of the neutron to proton and triton to helium-3 yield ratios,are directly related to effective mass splitting and can be used to probe the effective mass splitting.
基金supported by the National Research Foundation of Korea (NRF)funded by the Korean government (2021R1A4A3027878,2022M3H4A1A01012712)。
文摘Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and storage.By utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added chemicals.However,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical implementation.Recently,significant research has been conducted to improve the overall conversion efficiency of PEC devices.One particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy conversion.This review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) reduction.The main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/hydroxides.Meanwhile,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based cocatalysts.In addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with cocatalysts.Finally,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.
基金Supported by National Natural Science Foundation of China(NSFC) projects (Nos.11075215,10875031,11005022,11005155 and 11275052)973 Program of China(No.2013CB834404)National Science Foundation(Grants No.PHY-0606007)
文摘A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed.Based on the new code,four commonly used parameter sets,SLy4,SkI2,SkM*and Gs are adopted in the improved quantum molecular dynamics model and the isospin sensitive observables,namely isospin transport ratios,single and double ratios of the yields of neutrons and protons are investigated.The isospin transport ratios are strongly sensitive to the slope of symmetry energy,and are not very sensitive to the nucleon effective mass splitting.On the other hand,the high energy neutrons and protons yields ratios from reactions at different incident energies provide a good observable to the momentum dependence of nucleon effective mass splitting.By comparing our calculations with the data,we find that the constrained L value(the slope of density dependence of symmetry energy) is about ~46 MeV when the Skyrme type interaction is considered in transport models,and the isospin diffusion data prefer to mn*>mp*,but it is not a strong constraint with deep χ2minimum.
文摘As the demands of massive connections and vast coverage rapidly grow in the next wireless communication networks, rate splitting multiple access(RSMA) is considered to be the new promising access scheme since it can provide higher efficiency with limited spectrum resources. In this paper, combining spectrum splitting with rate splitting, we propose to allocate resources with traffic offloading in hybrid satellite terrestrial networks. A novel deep reinforcement learning method is adopted to solve this challenging non-convex problem. However, the neverending learning process could prohibit its practical implementation. Therefore, we introduce the switch mechanism to avoid unnecessary learning. Additionally, the QoS constraint in the scheme can rule out unsuccessful transmission. The simulation results validates the energy efficiency performance and the convergence speed of the proposed algorithm.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10774103 and 10974138)
文摘Based on the combination of Racah's group-theoretical consideration with Slater's wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3+ ion. Thus, the Stark energy-levels of Pr3+ ions doped separately in LiYF4 and LiBiF4 crystals are calculated, and our calculations imply that the complete energy matrix method can be used as an effective tool to calculate the energy-levels of the systems doped by rare earth ions. Besides, the influence of Pr3+ on energy-level splitting is investigated, and the similarities and the differences between the two doped crystals are demonstrated in detail by comparing their several pairs of curves and crystal field strength quantities. We see that the energy splitting patterns are similar and the crystal field interaction of LiYF4:Pr3+ is stronger than that of LiBiF4:Pr3+.
基金supported by the National Natural Science Foundation of China(Grant Nos.11274235 and 11104190)the Doctoral Education Fund of Education Ministry of China(Grant No.20110181120112)
文摘The inter-relation between zero-field splitting (ZFS) parameters and local lattice structures of the (CrSe4)6 clusters in ZnSe semiconductors has been established by using the complete diagonalization (of the energy matrix) method. On the basis of this, the local lattice distortions, the ZFS parameters D, a, F and the optical spectrum for Cr2+ ions doped into ZnSe are theoretically investigated, and the contributions of the spin singlets have been taken into account. The calculated ZFS parameters are in good agreement with the experimental values. From our calculations, the tetragonal distortion parameters AR = 0.091A and Aθ = 4.28° of Cr2+ in ZnSe are acquired, and the results suggest that there exists a tetragonal expansion distortion for the local lattice structure of (CrSe4)6- clusters in ZnSe crystals. The influence of the spin singlets on ZFS parameters is also discussed, indicating that the contributions to ZFS parameters a and F cannot be ignored.
基金Project(2010CL04) supported by the Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, ChinaProject(K-081025) supported by State Key Laboratory Breeding Base of Photocatalysis,Fuzhou University,China
文摘Using carbon felt,polytetrafluoroethylene latex and powder catalyst to assembly a light energy conversion device,the photocatalytic activity of catalyst 2.0%WO3-TiO2(2%WO3 compounding TiO2) with oxygen vacancies was studied through the water splitting for O2 evolution,using a high pressure mercury lamp as the light source and Fe 3+ as the electron acceptor in two different devices:an ordinary photolysis device with catalyst powder suspending through a magnetic stirrer and a self-assembly light energy conversion device.The results show that after 12 h irradiation,the photocatalytic activity of 2.0%WO3-TiO2 with oxygen vacancies in the self-assembly light energy conversion device is higher than that of the ordinary photolysis device,and the amount of oxygen evolution is about 12 and 9 mmol/L respectively in these two devices.After 12 h,the rates of O2 evolution are slow in each device and the photocatalyst almost loses the photoactivity in the ordinary photolysis device.So,compared with the ordinary photocatalytic device,the rate of oxygen evolution and the life time of the catalyst are improved in the self-assembly light energy conversion device.
文摘Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy).By means of improved ligand-field theory,the R line,t_2^(32)T_1 and t_2^(32)T_2 lines,t_2~2(~3T_1)e^4T_2,t_2~2(~3T_1)e^4T_1 and t_2e^2(~4A_2)~4T_1 bands,g factors of t_2~3 ~4A_2 and t_2^(32)E,four strain-induced level-splittings and R-line thermal shift of MgO:V^(2+) have been calculated.The results are in very good agreement with the experimental data.It is found that for MgO:V^(2+),the contributions due to electron- phonon interaction (EPI) come from the first-order term;the contributions from the second-order and higher terms are insignificant.In thermal shift of R line of MgO:V^(2+),the temperature-dependent contribution due to EPI is dominant. The results obtained in this work may be used in theoretical calculations of other effects of EPI.
基金supported by the National Natural Science Foundation of Chinathe Innovative Research Team in the University+4 种基金the Program for Changjiang Scholarsthe Fundamental Research Funds for the Central Universitiesthe longterm subsidy mechanism from the Ministry of Financethe Ministry of Education of People’s Republic of China (PRC)the Science and Engineering Research Board (SERB), Department of Science and Technology, Government of India (Reference No. PDF/2017/000015)
文摘Developing earth-abundant-electrocatalysts for hydrogen evolution reaction is one of the promising ways to achieve efficient water-splitting for hydrogen production(a clean chemical fuel).This paper reviews the activity,stability and durability for hydrogen evolution reaction in alkaline medium of different types of recently reported potential electrocatalysts such as Ni,Co,NiCo,Fe,Cu,W,Mo,Se,Mn.Zn,V,and metal free based earth-abundant-electrocatalysts.Further,this paper reviews the strategies used to achieve the remarkably low overpotential(including r/i0:<35mV),high long term stability(including^:100 h)and high durability(including>5000 cycles)of potential earth-abundant-electrocatalysts for hydrogen evolution reaction in alkaline medium and those are better or well comparable with the state-of-the-art,noble,Pt/C electrocatalyst.Finally,this paper summarizes the efficient strategies such as preparing porous structured materials,preparing nanostructured materials with superaerophobic surface,preparing nanostructured materials,preparing carbon composites/integrating electrocatalysts with carbon,preparing amorphous materials,preparing materials w让h oxygen vacancies/defects,preparing metal chalcogenides,preparing bimetallic/multi-metallic materials,doping metals or heteroatoms,preparing electrocatalysts with core-shell structure,decorating electrocatalysts with amines,preparing homojunction/heterojunction structured materials,preparing hollow structured materials,and preparing boronrich surface to enhance the activity,stability,and durability for HER.
基金supported by the King Abdullah University of Science and Technology(KAUST)。
文摘Tuning the electronic structure of the electrocatalysts for oxygen evolution reaction(OER)is a promising way to achieve efficient alkaline water splitting for clean energy production(H2).At first,this paper introduces the significance of the tuning of electronic structure,where modifying the electronic structure of the electrocatalysts could generate active sites having optimal adsorption energy with OER intermediates,and that could diminish the energy barrier for OER,and that could improve the activity for OER.Later,this paper reviews the tuning of electronic structure along with catalytic performances,synthetic methodologies,chemical properties,and DFT calculations on various nanostructured earth-abundant electrocatalysts for OER in alkaline environment.Further,this review discusses the tuning of the electronic structure of the several nanostructured earth-abundant electrocatalysts including oxide,(oxy)hydroxide,layered double hydroxide,alloy,metal phosphide/phosphate,nitride,sulfide,selenide,carbon containing materials,MOF,core-shell/hetero/hollow structured materials,and materials with vacancies/defects for OER in alkaline environment(including activity:overpotential(η)of ≤200 mV at10 m A cm^(-2);stability:≥100 h;durability:≥5000 cycles).Then,this review discusses the robust stability of the electrocatalysts for OER towards practical application.Moreover,this review discusses the in situ formation of thin layer on the catalyst surface during OER.In addition,this review discusses the influence of the adsorption energy of the OER intermediates on OER performance of the catalysts.Finally,this review summarizes the various promising strategies for tuning the electronic structure of the electrocatalysts to achieve enhanced performance for OER in alkaline environment.
基金supported by the Basic Science Center Program for Orderised Energy Conversion of the National Natural Science Foundation of China(No.51888103)。
文摘Photoelectrochemical(PEC)fuel generation from water splitting and CO_(2)reduction(CO_(2)R)utilizing solar energy holds immense potential to solve the current energy and environmental issues.In the past decades,numerous studies have been devoted to this fast-growing research field,and it is essential to develop efficient photoelectrodes with earth-abundant materials for the practical application of PEC systems.A thorough review of earth-abundant materials and associated devices for PEC fuel generation is beneficial to uncover the inherent obstacles and pave the way for future research.Herein,we summarize the recent progress of earth-abundant light-absorbers and cocatalysts in the PEC systems.The unbiased configurations and scaling-up strategies of PEC devices using earth-abundant materials are examined.A comparison between PEC water splitting and CO_(2)R is carried out to promote better understanding of the design principles for practical materials and devices.Last,the prospects on advanced materials,underlying mechanisms,and reaction systems of PEC water splitting and CO_(2)R are proposed.
基金the support of National Natural Science Foundation of China(No.11375123)
文摘Experiments of CO_2 splitting by dielectric barrier discharge(DBD) plasma were carried out, and the influence of CO_2 flow rate, plasma power, discharge voltage, discharge frequency on CO_2 conversion and process energy efficiency were investigated. It was shown that the absolute quantity of CO_2 decomposed was only proportional to the amount of conductive electrons across the discharge gap,and the electron amount was proportional to the discharge power; the energy efficiency of CO_2 conversion was almost a constant at a lower level, which was limited by CO_2 inherent discharge character that determined a constant gap electric field strength. This was the main reason why CO_2 conversion rate decreased as the CO_2 flow rate increase and process energy efficiency was decreased a little as applied frequency increased. Therefore, one can improve the CO_2 conversion by less feed flow rate or larger discharge power in DBD plasma, but the energy efficiency is difficult to improve.
基金Supported by National Natural Science Foundation of China(NSFC) projects (No.11175218)the Advancement Society of Young Innovation of Chinese Academy of Sciences
文摘Two different isospin splittings of nucleon effective mass in nuclear medium as the form of mn*>mp* and mn*<mp* have been implemented in an isospin and momentum dependent transport model.Their impacts on the isospin emission in heavy-ion collisions is investigated thoroughly.It is found that the yield ratios of energetic neutrons to protons squeezed out during the compression stage of two colliding nuclides are sensitive to the isospin splitting.The elliptic flows of free nucleons are also to be promising observables for extracting the nucleon effective mass splitting.Further experimental measurements are being expected,in particular at the CSR-CEE platform in Lanzhou.Several observables are proposed for constraining the density dependence of symmetry energy,such as the transverse flow difference of neutrons and protons,double ratios of n/p and π-/π+,excitation functions of π-/π+ and K0/K+.
基金supported by the Australian Research Council (ARC) Discovery Project (DP220101139)support of the Australian Research Council (ARC) through Project DE220100530support of the Australian Research Council (ARC) through Project DE200100970
文摘The sustainable production of green hydrogen via water electrolysis necessitates cost-effective electrocatalysts.By following the circular economy principle,the utilization of waste-derived catalysts significantly promotes the sustainable development of green hydrogen energy.Currently,diverse waste-derived catalysts have exhibited excellent catalytic performance toward hydrogen evolution reaction(HER),oxygen evolution reaction(OER),and overall water electrolysis(OWE).Herein,we systematically examine recent achievements in waste-derived electrocatalysts for water electrolysis.The general principles of water electrolysis and design principles of efficient electrocatalysts are discussed,followed by the illustration of current strategies for transforming wastes into electrocatalysts.Then,applications of waste-derived catalysts(i.e.,carbon-based catalysts,transitional metal-based catalysts,and carbon-based heterostructure catalysts)in HER,OER,and OWE are reviewed successively.An emphasis is put on correlating the catalysts’structure-performance relationship.Also,challenges and research directions in this booming field are finally highlighted.This review would provide useful insights into the design,synthesis,and applications of waste-derived electrocatalysts,and thus accelerate the development of the circular economy-driven green hydrogen energy scheme.
基金funded by a full scholarship(PD-071)from the Ministry of Higher Education of the Arab Republic of EgyptJSPS KAKENHI(21K18823)+3 种基金the Tatematsu FoundationCasio Science Promotion FoundationENEOS Tonengeneral Research/Development Encouragement&Scholarship FoundationJSPS KAKENHI(18H03841)。
文摘Photoelectrochemical water splitting(PEC-WS)is a promising technique for transforming solar energy into storable and environmentally friendly chemical energy.Designing semiconductor photoelectrodes with high light absorption capability,rapid e-/h+separation and transfer,and sufficient chemical stability is vital for developing an efficient PEC-WS system.Metal chalcogenides(MCs)have emerged as promising candidates for light absorbers because of their unique electrical and optical characteristics.In this review,we present recent developments in hydrogen generation via PEC-WS using MC-based photoelectrodes.First,we present a simple illustration of PEC-WS fundamentals.Second,the current performance of various metal(mono-,di-,and tri-)chalcogenide/semiconductor photoelectrodes in PEC-WS is summarized.Then,the charge transfer mechanism at the MC/semiconductor interface and the PEC-WS mechanism is thoroughly explained.Finally,we discuss future research perspectives toward developing efficient and stable MC/semiconductor photoelectrodes.