Hydrogen is an ideal clean energy because of its high calorific value and abundance of sources.However,storing hydrogen in a compact,inexpensive,and safe manner is the main restriction on the extensive utilization of ...Hydrogen is an ideal clean energy because of its high calorific value and abundance of sources.However,storing hydrogen in a compact,inexpensive,and safe manner is the main restriction on the extensive utilization of hydrogen energy.Magnesium(Mg)-based hydrogen storage material is considered a reliable solid hydrogen storage material with the advantages of high hydrogen storage capacity(7.6wt%),good performance,and low cost.However,the high thermodynamic stability and slow kinetics of Mg-based hydrogen storage materials have to be overcome.In this paper,we will review the recent advances in the nanoconfinement of Mg-related hydrogen storage materials by loading Mg particles on different supporting materials,including carbons,metal-organic frameworks,and other materials.Perspectives are also provided for designing high-performance Mg-based materials using nanoconfinement.展开更多
Polymeric materials under nanoconfinements have substantially deviated physical properties with respect to the bulk,especially glass transition temperature,physical aging,and crystallization behavior.Here we highlight...Polymeric materials under nanoconfinements have substantially deviated physical properties with respect to the bulk,especially glass transition temperature,physical aging,and crystallization behavior.Here we highlight the leading methods for creating various confinement systems.Upon these systems,recent advances on hard and soft confinement effect for glass transition,physical aging,mechanical properties and crystallization of polymers are reviewed in details.Furthermore,as nanoconfined systems in extreme conditions are experimentally inaccessible,simulation results describing confinement effect on such systems are also discussed.展开更多
Owing to its favorable thermodynamics and high density,NaAlH_(4) has been widely regarded as a potential hydrogen storage material,but its practical application is hindered by the sluggish kinetics,high operating temp...Owing to its favorable thermodynamics and high density,NaAlH_(4) has been widely regarded as a potential hydrogen storage material,but its practical application is hindered by the sluggish kinetics,high operating temperature and poor cycling stability.Here,taking advantage of Co-doped nanoporous carbon scaffolds as structural host,we develop a new strategy to balance the synergistic effect between the catalytic role of Co nanoparticles and the nanoconfinement role of porous carbon scaffolds via the controllable etching of Co nanoparticles towards enhanced hydrogen storage performance of NaAlH_(4).The etching of Co nanoparticles creates extra void spaces nearby catalytically active Co nanoparticles,which not only exerts the catalytic effect of Co nanoparticles,but also improves the nanoconfinement role in maintaining the cycling stability towards increased loading ratio and hence high systematic capacity.Induced by this balanced synergistic effect,the peak temperature for the dehydrogenation of NaAlH_(4) could be reduced to 164°C,97°C lower than the bulk counterpart,even under an ultrahigh loading ratio of 67%,and more importantly,the reversible systematic hydrogen storage capacity could still reach 3.3 wt.%after 5 cycles.This work opens up a new avenue to improve the hydrogen storage performance of various complex hydrides.展开更多
Rechargeable aluminum batteries(RABs),which use earth-abundant and high-volumetric-capacity metal anodes(8040 m Ah cm-3),have great potential as next-generation power sources because they use cheaper resources to deli...Rechargeable aluminum batteries(RABs),which use earth-abundant and high-volumetric-capacity metal anodes(8040 m Ah cm-3),have great potential as next-generation power sources because they use cheaper resources to deliver higher energies,compared to current lithium ion batteries.However,the mechanism of charge delivery in the newly developed,ionic liquid-based electrolytic system for RABs differs from that in conventional organic electrolytes.Thus,targeted research efforts are required to address the large overpotentials and cycling decay encountered in the ionic liquid-based electrolytic system.In this study,a nanoporous carbon(NPC)electrode with well-developed nanopores is used to develop a high-performance aluminum anode.The negatively charged nanopores can provide quenched dynamics of electrolyte molecules in the aluminum deposition process,resulting in an increased collision rate.The fast chemical equilibrium of anionic species induced by the facilitated anionic collisions leads to more favorable reduction reactions that form aluminum metals.The nanoconfinement effect causes separated nucleation and growth of aluminum nanoparticles in the multiple confined nanopores,leading to higher coulombic efficiencies and more stable cycling performance compared with macroporous carbon black and 2D stainless steel electrodes.展开更多
Understanding the integrated transport behavior of oil in shale nanopores is critical to efficient shale oil development. In this paper, based on the time-dependent Poiseuille flow momentum equation, we present a nove...Understanding the integrated transport behavior of oil in shale nanopores is critical to efficient shale oil development. In this paper, based on the time-dependent Poiseuille flow momentum equation, we present a novel transient model to describe oil transport in unsteady and steady states. The model incorporates the effect of the critical shift density, apparent viscosity, slip length, and alkane property, as well as pore tortuosity and surface roughness. We evaluated our model through a comparison with other models, experiments, and molecular dynamics simulations. The results show that the development rates of the volume flows of C_(6)–C_(12) alkane confined in inorganic nanopores and C_(12) alkane confined in organic nanopores were faster than that of the corresponding bulk alkane. In addition, the critical drift density positively promoted the volume flow development rate in the unsteady state and negatively inhibited the mass flow rate in the steady state. This effect was clearest in pores with a smaller radius and lower-energy wall and in alkane with shorter chain lengths. Furthermore, both the nanoconfinement effect and pore structure determined whether the volume flow enhancement rate was greater than or less than 1. The rate increased or decreased with time and was controlled mainly by the nanoconfinement effect. Moreover, as the wall energy increased, the flow inhibition effect increased;as the carbon number of alkane increased, the flow promotion effect increased. The results indicate that the proposed model can accurately describe oil transport in shale nanopores.展开更多
Secondary batteries are widely used in energy storage equipment.To obtain high-performance batteries,the development and utilization of electrode materials with cheap price and ideal theoretical gravimetric and volume...Secondary batteries are widely used in energy storage equipment.To obtain high-performance batteries,the development and utilization of electrode materials with cheap price and ideal theoretical gravimetric and volumetric specific capacities have become particularly important.Naturally abundant and low-cost red phosphorus(RP)is recognized as an anode material with great promise because it has a theoretical capacity of 2596 mA h g^(-1) in lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs).However,owing to the inferior discharging,the capacity of pure RP has a fast decay.Nanoconfinement of RP nanoparticles within porous carbon framework is one of the efficient methods to overcome these problems.In this review,we introduce the recent progress of RP confinement into carbon matrix as an energy storage anode material in LIBs,SIBs and potassium-ion batteries(PIBs).The synthetic strategies,lithiation/sodia tion/potassiation mechanism,and the electrochemical performances of RP/carbon composites(RP/C)with kinds of designed structures and P-C and P-O-C bond by kinds of methods are included.Finally,the challenges and perspectives of RP faced in the application development as anodes for LIBs/SIBs/PIBs are covered.This review will strengthen the understanding of composites of RP nanoparticles in porous carbon materials and aid researchers to carry out future work rationally.展开更多
Water is an indispensable resource for all life on the Earth.However,the exacerbating water scarcity and emerging pollutants increasingly challenge conventional water treatment infrastructure.The emergence of nanotech...Water is an indispensable resource for all life on the Earth.However,the exacerbating water scarcity and emerging pollutants increasingly challenge conventional water treatment infrastructure.The emergence of nanotechnology and its incorporation into water purification systems marks a transformative development in addressing these issues.While nanotechnology applications in water treatment have evolved significantly since the late 1990s,industrial implementation barriers persist,including challenges in mass nanomaterial production,inherent particle aggregation tendencies,potential environmental leakage,and compatibility issues with existing infrastructure and complex water matrices.展开更多
For a clean and sustainable society,there is an urgent demand for renewable energy with net‐zero emissions due to fossil fuels limited resources and irreversible environmental impact.Hydrogen has the unrivaled potent...For a clean and sustainable society,there is an urgent demand for renewable energy with net‐zero emissions due to fossil fuels limited resources and irreversible environmental impact.Hydrogen has the unrivaled potential to replace fossil fuels due to its high gravimetric energy density,abundant sources(H_(2)O),and environmental friendliness.However,its low volumetric energy density causes significant challenges,inspiring major efforts to develop chemical‐based storage alternatives.Solid‐state hydrogen storage in materials has substantial potential for fulfilling the practical requirements and is recognized as a potential candidate due to their properties tuning more independently.However,hydrogen's stable thermodynamics and sluggish kinetics are the bottleneck to its widespread applications.To explore the kinetic and thermodynamic barriers in the fundamentals of hydrogen storage materials,this review will provide promising information for researchers to gain detailed knowledge about hydrogen storage energy applications and find new routes for materials engineering with tuned properties.This will further attract a wider scientific community and intend to understand the innovative concepts and strategies developed and to employ them in tailoring hydrogen storage materials'kinetic and thermodynamic properties.Recent advances in nanostructuring,nanoconfinement with in situ catalysts,and host/vip stress/strain engineering have the potential to propel the prospects of tailoring the hydrogen storage materials properties at the nanoscale with several promising directions and strategies that could lead to the next generation of solid‐state hydrogen storage practical applications.展开更多
While industrial wastewater discharge causes pollution,it also contains abundant neglected energy.However,establishing effective methods for energy harvesting and real-time monitoring of pollution sources is a serious...While industrial wastewater discharge causes pollution,it also contains abundant neglected energy.However,establishing effective methods for energy harvesting and real-time monitoring of pollution sources is a serious challenge,and includes high-salt solution accompanying nickel ions(Ni(II))in the electroplating industry.Here,a nanoconfinement channel design strategy was adopted to custombuild a three-dimensional(3D)interpenetrating ion channel of metal–organic frameworks(MOFs).By introducing specific functional groups,the charge density of the ion channels could be adjusted.Osmotic energy harvesting achieved a maximumoutput power density of 9.1 W/m^(2),which was 6-fold greater than that of the typical commercial material,UiO-67,known to possess enhanced water stability and methane adsorption capacity.Benefiting from the spatial distribution design of functional groups in the nanoconfinement channels enabled excellent ion selectivity and optimal energy harvesting.Meanwhile,the nanoconfinement channels and functional groups collaborate to create a sensitive ion concentration detection space,presenting a well-designed modified ion channel for emission standards.When Ni(II)appeared,the current signal decreased by∼20-fold.The tripartite cooperation of functional groups,nanoconfinement,and Ni(II)-enabled stable and accurate detection ensured smooth working progress.This study not only provides a design strategy for energy harvesting and detection but also inspires the future design of integrated devices.展开更多
Water friction in nanoconfinement is of great importance in water lubrication and membrane-based applications,yet remains fraught with doubts despite great efforts.Our molecular dynamics simulations demonstrate that t...Water friction in nanoconfinement is of great importance in water lubrication and membrane-based applications,yet remains fraught with doubts despite great efforts.Our molecular dynamics simulations demonstrate that the first water layer adjacent to the surface plays an important role in interfacial friction.Applying a uniform strain to the surface(changing the lattice constant)can induce a significant change in friction and is quite different for the hydrophilic and hydrophobic cases.Specifically,in the hydrophilic case,there is maximum friction when the lattice constant approaches the preferential oxygen‒oxygen distance of the first water layer(a constant value),and the further it deviates,the smaller the friction.The maximum friction corresponds to the most ordered first water layer.While in the hydrophobic case,the friction increases monotonically with increasing lattice constant,which hardly changes the first water layer structure but only increases the difficulty of water molecular jump(meaning jump from one equilibrium position to another).Starting from the molecular jump in the first water layer,theoretical dependence of friction on the molecular activation barrier and shear velocity is established,which provides a reasonable explanation for the friction behavior.Moreover,the water transport behavior in nanochannels supports the finding of the friction dependence on the lattice constant,suggesting great potential for improving and controlling water transport.Our results not only provide a novel understanding of nanoconfined water friction but are also instructive for friction control and water transport.展开更多
Nanoconfinement is a promising approach to simultaneously enhance the thermodynamics,kinetics,and cycling stability of hydrogen storage materials.The introduction of supporting scaffolds usually causes a reduction in ...Nanoconfinement is a promising approach to simultaneously enhance the thermodynamics,kinetics,and cycling stability of hydrogen storage materials.The introduction of supporting scaffolds usually causes a reduction in the total hydrogen storage capacity due to“dead weight.”Here,we synthesize an optimized N-doped porous carbon(rN-pC)without heavy metal as supporting scaffold to confine Mg/MgH_(2) nanoparticles(Mg/MgH_(2)@rN-pC).rN-pC with 60 wt%loading capacity of Mg(denoted as 60 Mg@rN-pC)can adsorb and desorb 0.62 wt%H_(2) on the rN-pC scaffold.The nanoconfined MgH_(2) can be chemically dehydrided at 175℃,providing~3.59 wt%H_(2) with fast kinetics(fully dehydrogenated at 300℃ within 15 min).This study presents the first realization of nanoconfined Mg-based system with adsorption-active scaffolds.Besides,the nanoconfined MgH_(2) formation enthalpy is reduced to~68 kJ mol^(−1) H_(2) from~75 kJ mol^(−1) H_(2) for pure MgH_(2).The composite can be also compressed to nanostructured pellets,with volumetric H_(2) density reaching 33.4 g L^(−1) after 500 MPa compression pressure,which surpasses the 24 g L^(−1) volumetric capacity of 350 bar compressed H_(2).Our approach can be implemented to the design of hybrid H_(2) storage materials with enhanced capacity and desorption rate.展开更多
In the pursuit of heterogeneous catalysts with high reactivity,metal organic framework(MOF)nanomaterials have received tremendous attentions.However,many MOF catalysts especially Fe-based MOFs need to be utilized imme...In the pursuit of heterogeneous catalysts with high reactivity,metal organic framework(MOF)nanomaterials have received tremendous attentions.However,many MOF catalysts especially Fe-based MOFs need to be utilized immediately after synthesis or being activated using high temperature,because of the easy loss of reactivity in humid environments resulting from the occupation of active Fe sites by water molecules.Here,we describe an inspiring strategy of growing MIL-101-Fe nanoparticles inside the three-dimensional confined space of graphene aerogel(GA),generating shapeable GA/MIL-101-Fe nanocomposite convenient for practical use.Compared to MIL-101-Fe,GA/MIL-101-Fe as catalyst demonstrates much higher reactivity in Fenton-like reaction,attributing to smaller MIL-101-Fe particle size,presence of active Fe(II)sites,and abundant defects in GA.Strikingly,the weakly hydrophobic nature of the composite greatly inhibits the loss of catalytic reactivity after being stored in humid air and accelerates the recovery of reactivity in mild temperature,by resisting the entrance of water molecules and helping to exclude water molecules.This work demonstrates that a delicate design of nanocomposite structure could not only improve the reactivity of the catalytic component,but also overcome its intrinsic drawback by taking advantage of the properties of host.We hope this functional nanoconfinement strategy could be extended to more scenarios in other fields.展开更多
The characterization of kerogen nanopores is crucial for predicting the geostorage capacity and recoverability of natural gas in unconventional gas shale reservoirs.Towards this end,a powerful technique is presented w...The characterization of kerogen nanopores is crucial for predicting the geostorage capacity and recoverability of natural gas in unconventional gas shale reservoirs.Towards this end,a powerful technique is presented which integrates 2D NMR T_(1)-T_(2) relaxation measurements with molecular dynamics(MD)simulations of hydrocarbons confined in the nanopores of kerogen.The integrated NMR-MD technique is demonstrated using T_(1)-T_(2) measurements of kerogen isolates and organic-rich chalks saturated with heptane,together with MD simulations of heptane completely dissolved in a realistic kerogen model.The NMR-MD results are used to extract the swelling ratio and nanopore size distribution of kerogen as a function of depth in the reservoir.The effects of organic nanoconfinement on the T_(1) relaxation dispersion and T_(2) residual dipolar coupling of heptane are investigated,as well as the effect of downhole effective stress on the kerogen nanopore size as a function of depth and compaction.Potential applications in partially depleted gas shale reservoirs are discussed,including CO_(2) utilization/geostorage,geostorage of green H_(2),and integration of the NMR-MD technique with thermodynamic models for predicting the competitive sorption of gas mixtures in kerogen.展开更多
Available online Further oxidation of NH3produced via photocatalytic N_(2)fixation represents a promising strategy to enhance the economic value of N_(2)fixation.This work employs first-principles density functional t...Available online Further oxidation of NH3produced via photocatalytic N_(2)fixation represents a promising strategy to enhance the economic value of N_(2)fixation.This work employs first-principles density functional theory(DFT)calculations to demonstrate that incorporating Co into Ni O improves both N_(2)adsorption and activation as well as M-N electron exchange intensity.Guided by these predictions,a novel Co single-atom photocatalyst supported by nanoconfined Ni O@C nanosheets was synthesized using a direct metal atomization method,achieving high HNO_(3)production(60.54%).NH_(4)^(+)and NO_(3)^(-)production rates during N_(2)photofixation reached 67.97μmol g_(cat)^(-1)h^(-1)and 104.28μmol g_(cat)^(-1)h^(-1),respectively.The overall N_(2)→NH_(3)→HNO_(3)photofixation pathway was validated through in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and^(15)N isotopic labeling.Mechanistic studies reveal that Co single-atom introduction serves as an electron trap,enhancing photogenerated electron accumulation with a five-fold increase in carrier density compared to Ni O@C,as observed via in-situ X-ray photoelectron spectroscopy(XPS).This synergistic effect between electron traps and N2adsorption/activation sites at Co single-atom centers supports rapid N_(2)reduction kinetics.Additionally,nanoconfined ink-bottle pores in the carbon layer impede NH_(3)desorption,further boosting NO_(3)-production.This work offers a comprehensive approach to optimizing N_(2)photofixation through electron regulation and surface reaction kinetics.展开更多
MgH_(2) has attracted intensive interests as one of the most promising hydrogen storage materials.Nevertheless,the high desorption temperature,sluggish kinetics,and rapid capacity decay hamper its commercial applicati...MgH_(2) has attracted intensive interests as one of the most promising hydrogen storage materials.Nevertheless,the high desorption temperature,sluggish kinetics,and rapid capacity decay hamper its commercial application.Herein,2D TiO_(2) nanosheets with abundant oxygen vacancies are used to fabricate a flower-like MgH_(2)/TiO_(2) heterostructure with enhanced hydrogen storage performances.Particularly,the onset hydrogen desorption temperature of the MgH_(2)/TiO_(2) heterostructure is lowered down to 180℃(295℃ for blank MgH_(2)).The initial desorption rate of MgH_(2)/TiO_(2) reaches 2.116 wt% min^(-1) at 300℃,35 times of the blank MgH_(2) under the same conditions.Moreover,the capacity retention is as high as 98.5% after 100 cycles at 300℃,remarkably higher than those of the previously reported MgH_(2)-TiO_(2) composites.Both in situ HRTEM observations and ex situ XPS analyses confirm that the synergistic effects from multi-valance of Ti species,accelerated electron transportation caused by oxygen vacancies,formation of catalytic Mg-Ti oxides,and stabilized MgH_(2) NPs confined by TiO_(2) nanosheets contribute to the high stability and kinetically accelerated hydrogen storage performances of the composite.The strategy of using 2D substrates with abundant defects to support nano-sized energy storage materials to build heterostructure is therefore promising for the design of high-performance energy materials.展开更多
Unveiling the pore-size performance of metal organic frameworks(MOFs)is imperative for controllable design of sophisticated catalysts.Herein,UiO-66 with distinct macropores and mesopores were intentionally created and...Unveiling the pore-size performance of metal organic frameworks(MOFs)is imperative for controllable design of sophisticated catalysts.Herein,UiO-66 with distinct macropores and mesopores were intentionally created and served as substrates to create advanced CdS/UiO-66 catalysts.The pore size impacted the spatial distribution of CdS nanoparticles(NPs):CdS tended to deposit on the external surface of mesoporous UiO-66,but spontaneously penetrated into the large cavity of macroporous UiO-66 nanocage.Normalized to unit amount of CdS,the photocatalytic reaction constant of macroporous CdS/UiO-66 over 4-nitroaniline reduction was~3 folds of that of mesoporous counterpart,and outperformed many other reported state-of-art CdS-based catalysts.A confinement effect of CdS NPs within UiO-66 cage could respond for its high activity,which could shorten the electron-transport distance of NPs-MOFs-reactant,and protect the active CdS NPs from photocorrosion.The finding here provides a straightforward paradigm and mechanism to rationally fabricate advance NPs/MOFs for diverse applications.展开更多
Water scarcity is a global challenge,and solar evaporation technology offers a promising and eco-friendly solution for freshwater production.Photothermal conversion materials(PCMs)are crucial for solar evaporation.Imp...Water scarcity is a global challenge,and solar evaporation technology offers a promising and eco-friendly solution for freshwater production.Photothermal conversion materials(PCMs)are crucial for solar evaporation.Improving photothermal conversion efficiency and reducing water evaporation enthalpy are the two key strategies for the designing of PCMs.The desired PCMs that combine both of these properties remain a challenging task,even with the latest advancements in the field.Herein,we developed copper nanoparticles(NPs)with different conjugated nitrogen-doped microporous carbon coatings(Cu@C–N)as PCMs.The microporous carbon enveloping layer provides a highly efficient pathway for water transport and a nanoconfined environment that protects Cu NPs and facilitates the evaporation of water clusters,reducing the enthalpy of water evaporation.Meanwhile,the conjugated nitrogen nodes form strong metal-organic coordination bonds with the surface of copper NPs,acting as an energy bridge to achieve rapid energy transfer and provide high solar-to-vapor conversion efficiency.The Cu@C–N exhibited up to 89.4%solar-to-vapor conversion efficiency and an evaporation rate of 1.94 kgm^(−2) h^(−1) under one sun irradiation,outperforming conventional PCMs,including carbon-based materials and semiconductor materials.These findings offer an efficient design scheme for high-performance PCMs essential for solar evaporators to address global water scarcity.展开更多
In molecular modeling of electrical double layers(EDLs),the constant charge method(CCM)is prized for its computational efficiency but cannot maintain electrode equipotentiality like the more resourceintensive constant...In molecular modeling of electrical double layers(EDLs),the constant charge method(CCM)is prized for its computational efficiency but cannot maintain electrode equipotentiality like the more resourceintensive constant potential method(CPM),potentially leading to inaccuracies.In certain scenarios,CCM can yield results identical to CPM.However,there are no clear guidelines to determine when CCM is sufficient and when CPM is required.Here,we conduct a series of molecular simulations across various electrodes and electrolytes to present a comprehensive comparison between CCM and CPM under different charging modes.Results reveal that CCM approximates CPM effectively in capturing equilibrium EDL and current-driven dynamics in open electrode systems featuring ionic liquids or regular concentration aqueous electrolytes,while CPM is indispensable in scenarios involving organic and highly concentrated aqueous electrolytes,nanoconfinement effects,and voltage-driven dynamics.This work helps to select appropriate methods for modeling EDL systems,prioritizing accuracy while considering computationalefficiency.展开更多
Ca^(2+)/Na+separation is a common problem in industrial applications,biological and medical fields.However,Ca^(2+)and Na+have similar ionic radii and hydration radii,thus Ca^(2+)/Na+separation is challenging.Inspired ...Ca^(2+)/Na+separation is a common problem in industrial applications,biological and medical fields.However,Ca^(2+)and Na+have similar ionic radii and hydration radii,thus Ca^(2+)/Na+separation is challenging.Inspired by biological channels,group modification is one of the effective methods to improve the separation performance.In this work,molecular dynamics simulations were performed to investigate the effects of different functional groups(COO,NH3+)on the separation performance of Ca^(2+)and Na+through graphene nanopores under an electric field.The pristine graphene nanopore was used for comparison.Results showed that three types of nanopores preferred Ca^(2+)to Na+,and Ca^(2+)/Na+selectivity followed the order of GE-COO(4.06)>GE(1.85)>GE-NH3+(1.63).Detailed analysis of ionic hydration microstructure shows that different nanopores result in different hydration factors for the second hydration layer of Ca^(2+)and the first layer of Na+.Such different hydration factors corresponding to the dehydration ability can effectively evaluate the separation performance.In addition,the breaking of hydrogen bonds between water molecules due to electrostatic effects can directly affect the dehydration ability.Therefore,the electrostatic effect generated by group modification will affect the ionic hydration microstructure,thus reflecting the differences in dehydration ability.This in turn affects the permeable and separation performance of cations.The results of this work provide perceptive guidelines for the application of graphene-based membranes in ion separation.展开更多
基金financially supported by the research programs of the National Natural Science Foundation of China (No. 52101274)the Natural Science Foundation of Shandong Province, China (No. ZR2020QE011)the Youth Top Talent Foundation of Yantai University, China (No. 2219008)
文摘Hydrogen is an ideal clean energy because of its high calorific value and abundance of sources.However,storing hydrogen in a compact,inexpensive,and safe manner is the main restriction on the extensive utilization of hydrogen energy.Magnesium(Mg)-based hydrogen storage material is considered a reliable solid hydrogen storage material with the advantages of high hydrogen storage capacity(7.6wt%),good performance,and low cost.However,the high thermodynamic stability and slow kinetics of Mg-based hydrogen storage materials have to be overcome.In this paper,we will review the recent advances in the nanoconfinement of Mg-related hydrogen storage materials by loading Mg particles on different supporting materials,including carbons,metal-organic frameworks,and other materials.Perspectives are also provided for designing high-performance Mg-based materials using nanoconfinement.
基金The authorsacknowledge the National Natural Science Foundation of China for financial support through the General Program No.2157408.Y.G.is very grateful to the National Youth 1000 Talent Program of China,the Shanghai 1000 Talent Plan,and the support by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China.The authors also acknowledge the start-up fund of Y.G.from both University of Michigan-Shanghai Jiao Tong University Joint Institute,and School of Materials Science and Engineering at SJTU.
文摘Polymeric materials under nanoconfinements have substantially deviated physical properties with respect to the bulk,especially glass transition temperature,physical aging,and crystallization behavior.Here we highlight the leading methods for creating various confinement systems.Upon these systems,recent advances on hard and soft confinement effect for glass transition,physical aging,mechanical properties and crystallization of polymers are reviewed in details.Furthermore,as nanoconfined systems in extreme conditions are experimentally inaccessible,simulation results describing confinement effect on such systems are also discussed.
基金This work was partially supported by the National Key R&D Program of China(No.2018YFB1502101)National Science Fund for Distinguished Young Scholars(51625102)+3 种基金the National Natural Science Foundation of China(51971065,51901045)the Innovation Program of Shanghai Municipal Education Commission(2019-01-07-00-07-E00028)the Open Fund of the Guangdong Provincial Key Laboratory of Advanced Energy Storage Materialsthe Programs for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning。
文摘Owing to its favorable thermodynamics and high density,NaAlH_(4) has been widely regarded as a potential hydrogen storage material,but its practical application is hindered by the sluggish kinetics,high operating temperature and poor cycling stability.Here,taking advantage of Co-doped nanoporous carbon scaffolds as structural host,we develop a new strategy to balance the synergistic effect between the catalytic role of Co nanoparticles and the nanoconfinement role of porous carbon scaffolds via the controllable etching of Co nanoparticles towards enhanced hydrogen storage performance of NaAlH_(4).The etching of Co nanoparticles creates extra void spaces nearby catalytically active Co nanoparticles,which not only exerts the catalytic effect of Co nanoparticles,but also improves the nanoconfinement role in maintaining the cycling stability towards increased loading ratio and hence high systematic capacity.Induced by this balanced synergistic effect,the peak temperature for the dehydrogenation of NaAlH_(4) could be reduced to 164°C,97°C lower than the bulk counterpart,even under an ultrahigh loading ratio of 67%,and more importantly,the reversible systematic hydrogen storage capacity could still reach 3.3 wt.%after 5 cycles.This work opens up a new avenue to improve the hydrogen storage performance of various complex hydrides.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)Funded by the Ministry of Education(NRF-2019R1A2C1084836,NRF-2018M1A2A2061994,and NRF-2021R1A4A2001403)the KU-KIST School Program。
文摘Rechargeable aluminum batteries(RABs),which use earth-abundant and high-volumetric-capacity metal anodes(8040 m Ah cm-3),have great potential as next-generation power sources because they use cheaper resources to deliver higher energies,compared to current lithium ion batteries.However,the mechanism of charge delivery in the newly developed,ionic liquid-based electrolytic system for RABs differs from that in conventional organic electrolytes.Thus,targeted research efforts are required to address the large overpotentials and cycling decay encountered in the ionic liquid-based electrolytic system.In this study,a nanoporous carbon(NPC)electrode with well-developed nanopores is used to develop a high-performance aluminum anode.The negatively charged nanopores can provide quenched dynamics of electrolyte molecules in the aluminum deposition process,resulting in an increased collision rate.The fast chemical equilibrium of anionic species induced by the facilitated anionic collisions leads to more favorable reduction reactions that form aluminum metals.The nanoconfinement effect causes separated nucleation and growth of aluminum nanoparticles in the multiple confined nanopores,leading to higher coulombic efficiencies and more stable cycling performance compared with macroporous carbon black and 2D stainless steel electrodes.
基金supported by the National Natural Science Foundation for Youths of China(Grant No.12201374)the Scientific Research Foundation of Education Department of Shaanxi Province(Grant No.22JK0315)+2 种基金the Research Foundation for the Doctoral Program of Shaanxi University of Technology(Grant No.SLGRCQD2136)the Key R&D Plan,Shaanxi Province(2022GY-138)the Science and Technology Plan Project,Guizhou Province([2022]ZD005).
文摘Understanding the integrated transport behavior of oil in shale nanopores is critical to efficient shale oil development. In this paper, based on the time-dependent Poiseuille flow momentum equation, we present a novel transient model to describe oil transport in unsteady and steady states. The model incorporates the effect of the critical shift density, apparent viscosity, slip length, and alkane property, as well as pore tortuosity and surface roughness. We evaluated our model through a comparison with other models, experiments, and molecular dynamics simulations. The results show that the development rates of the volume flows of C_(6)–C_(12) alkane confined in inorganic nanopores and C_(12) alkane confined in organic nanopores were faster than that of the corresponding bulk alkane. In addition, the critical drift density positively promoted the volume flow development rate in the unsteady state and negatively inhibited the mass flow rate in the steady state. This effect was clearest in pores with a smaller radius and lower-energy wall and in alkane with shorter chain lengths. Furthermore, both the nanoconfinement effect and pore structure determined whether the volume flow enhancement rate was greater than or less than 1. The rate increased or decreased with time and was controlled mainly by the nanoconfinement effect. Moreover, as the wall energy increased, the flow inhibition effect increased;as the carbon number of alkane increased, the flow promotion effect increased. The results indicate that the proposed model can accurately describe oil transport in shale nanopores.
基金financially supported by the National Natural Science Foundation of China(51808303 and 51672143)the Science and Technology Support Plan for Youth Innovation of Colleges in Shandong Province(DC2000000961)+2 种基金the Taishan Scholar Program,Outstanding Youth of Natural Science in Shandong Province(JQ201713)the Natural Science Foundation of Shandong Province(ZR2019BEE027)the State Key Laboratory of BioFibers and Eco-Textiles(Qingdao University,No.ZKT25 and ZKT30)。
文摘Secondary batteries are widely used in energy storage equipment.To obtain high-performance batteries,the development and utilization of electrode materials with cheap price and ideal theoretical gravimetric and volumetric specific capacities have become particularly important.Naturally abundant and low-cost red phosphorus(RP)is recognized as an anode material with great promise because it has a theoretical capacity of 2596 mA h g^(-1) in lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs).However,owing to the inferior discharging,the capacity of pure RP has a fast decay.Nanoconfinement of RP nanoparticles within porous carbon framework is one of the efficient methods to overcome these problems.In this review,we introduce the recent progress of RP confinement into carbon matrix as an energy storage anode material in LIBs,SIBs and potassium-ion batteries(PIBs).The synthetic strategies,lithiation/sodia tion/potassiation mechanism,and the electrochemical performances of RP/carbon composites(RP/C)with kinds of designed structures and P-C and P-O-C bond by kinds of methods are included.Finally,the challenges and perspectives of RP faced in the application development as anodes for LIBs/SIBs/PIBs are covered.This review will strengthen the understanding of composites of RP nanoparticles in porous carbon materials and aid researchers to carry out future work rationally.
基金supported by the National Key Research and Development Program of China(2022YFA1205601 and 2022YFA1205602)the National Natural Science Foundation of China(22236003,22376093,and 22306091)the Natural Science Foundation of Jiangsu Province(BK20230797).
文摘Water is an indispensable resource for all life on the Earth.However,the exacerbating water scarcity and emerging pollutants increasingly challenge conventional water treatment infrastructure.The emergence of nanotechnology and its incorporation into water purification systems marks a transformative development in addressing these issues.While nanotechnology applications in water treatment have evolved significantly since the late 1990s,industrial implementation barriers persist,including challenges in mass nanomaterial production,inherent particle aggregation tendencies,potential environmental leakage,and compatibility issues with existing infrastructure and complex water matrices.
基金supported by the Embassy of the People's Republic of China in Malaysia(EENG/0045)funded by Xiamen University Malaysia Investigatorship Grant(Grant no:IENG/0038)Xiamen University Malaysia Research Fund(ICOE/0001,XMUMRF/2021‐C8/IENG/0041,and XMUMRF/2025‐C15/IENG/0080).
文摘For a clean and sustainable society,there is an urgent demand for renewable energy with net‐zero emissions due to fossil fuels limited resources and irreversible environmental impact.Hydrogen has the unrivaled potential to replace fossil fuels due to its high gravimetric energy density,abundant sources(H_(2)O),and environmental friendliness.However,its low volumetric energy density causes significant challenges,inspiring major efforts to develop chemical‐based storage alternatives.Solid‐state hydrogen storage in materials has substantial potential for fulfilling the practical requirements and is recognized as a potential candidate due to their properties tuning more independently.However,hydrogen's stable thermodynamics and sluggish kinetics are the bottleneck to its widespread applications.To explore the kinetic and thermodynamic barriers in the fundamentals of hydrogen storage materials,this review will provide promising information for researchers to gain detailed knowledge about hydrogen storage energy applications and find new routes for materials engineering with tuned properties.This will further attract a wider scientific community and intend to understand the innovative concepts and strategies developed and to employ them in tailoring hydrogen storage materials'kinetic and thermodynamic properties.Recent advances in nanostructuring,nanoconfinement with in situ catalysts,and host/vip stress/strain engineering have the potential to propel the prospects of tailoring the hydrogen storage materials properties at the nanoscale with several promising directions and strategies that could lead to the next generation of solid‐state hydrogen storage practical applications.
基金National Natural Science Foundation of China(grant nos.22373042 and 22341301)the Excellent Young Scientific and Technological Talents of Jilin Province Project(grant no.20240602013RC)+1 种基金the Science and Technology Major Project of Jilin Province(grant no.20240208001JH)the Fundamental Research Funds for the Central Universities.
文摘While industrial wastewater discharge causes pollution,it also contains abundant neglected energy.However,establishing effective methods for energy harvesting and real-time monitoring of pollution sources is a serious challenge,and includes high-salt solution accompanying nickel ions(Ni(II))in the electroplating industry.Here,a nanoconfinement channel design strategy was adopted to custombuild a three-dimensional(3D)interpenetrating ion channel of metal–organic frameworks(MOFs).By introducing specific functional groups,the charge density of the ion channels could be adjusted.Osmotic energy harvesting achieved a maximumoutput power density of 9.1 W/m^(2),which was 6-fold greater than that of the typical commercial material,UiO-67,known to possess enhanced water stability and methane adsorption capacity.Benefiting from the spatial distribution design of functional groups in the nanoconfinement channels enabled excellent ion selectivity and optimal energy harvesting.Meanwhile,the nanoconfinement channels and functional groups collaborate to create a sensitive ion concentration detection space,presenting a well-designed modified ion channel for emission standards.When Ni(II)appeared,the current signal decreased by∼20-fold.The tripartite cooperation of functional groups,nanoconfinement,and Ni(II)-enabled stable and accurate detection ensured smooth working progress.This study not only provides a design strategy for energy harvesting and detection but also inspires the future design of integrated devices.
基金financial support from the National Natural Science Foundation of China(No.22032006)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB047020104).
文摘Water friction in nanoconfinement is of great importance in water lubrication and membrane-based applications,yet remains fraught with doubts despite great efforts.Our molecular dynamics simulations demonstrate that the first water layer adjacent to the surface plays an important role in interfacial friction.Applying a uniform strain to the surface(changing the lattice constant)can induce a significant change in friction and is quite different for the hydrophilic and hydrophobic cases.Specifically,in the hydrophilic case,there is maximum friction when the lattice constant approaches the preferential oxygen‒oxygen distance of the first water layer(a constant value),and the further it deviates,the smaller the friction.The maximum friction corresponds to the most ordered first water layer.While in the hydrophobic case,the friction increases monotonically with increasing lattice constant,which hardly changes the first water layer structure but only increases the difficulty of water molecular jump(meaning jump from one equilibrium position to another).Starting from the molecular jump in the first water layer,theoretical dependence of friction on the molecular activation barrier and shear velocity is established,which provides a reasonable explanation for the friction behavior.Moreover,the water transport behavior in nanochannels supports the finding of the friction dependence on the lattice constant,suggesting great potential for improving and controlling water transport.Our results not only provide a novel understanding of nanoconfined water friction but are also instructive for friction control and water transport.
基金supported by the National Key R&D Program of China(2022YFB3803700)National Natural Science Foundation of China(52171186)+1 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)support from“Zhiyuan Honor Program”for doctoral students,Shanghai Jiao Tong University.
文摘Nanoconfinement is a promising approach to simultaneously enhance the thermodynamics,kinetics,and cycling stability of hydrogen storage materials.The introduction of supporting scaffolds usually causes a reduction in the total hydrogen storage capacity due to“dead weight.”Here,we synthesize an optimized N-doped porous carbon(rN-pC)without heavy metal as supporting scaffold to confine Mg/MgH_(2) nanoparticles(Mg/MgH_(2)@rN-pC).rN-pC with 60 wt%loading capacity of Mg(denoted as 60 Mg@rN-pC)can adsorb and desorb 0.62 wt%H_(2) on the rN-pC scaffold.The nanoconfined MgH_(2) can be chemically dehydrided at 175℃,providing~3.59 wt%H_(2) with fast kinetics(fully dehydrogenated at 300℃ within 15 min).This study presents the first realization of nanoconfined Mg-based system with adsorption-active scaffolds.Besides,the nanoconfined MgH_(2) formation enthalpy is reduced to~68 kJ mol^(−1) H_(2) from~75 kJ mol^(−1) H_(2) for pure MgH_(2).The composite can be also compressed to nanostructured pellets,with volumetric H_(2) density reaching 33.4 g L^(−1) after 500 MPa compression pressure,which surpasses the 24 g L^(−1) volumetric capacity of 350 bar compressed H_(2).Our approach can be implemented to the design of hybrid H_(2) storage materials with enhanced capacity and desorption rate.
基金The authors thanked the financial support from the National Natural Science Foundation of China(No.21925602)Natural Science Foundation of Jiangsu Province(No.BK20201309)the Fundamental Research Funds for the Central Universities(No.30920021116).
文摘In the pursuit of heterogeneous catalysts with high reactivity,metal organic framework(MOF)nanomaterials have received tremendous attentions.However,many MOF catalysts especially Fe-based MOFs need to be utilized immediately after synthesis or being activated using high temperature,because of the easy loss of reactivity in humid environments resulting from the occupation of active Fe sites by water molecules.Here,we describe an inspiring strategy of growing MIL-101-Fe nanoparticles inside the three-dimensional confined space of graphene aerogel(GA),generating shapeable GA/MIL-101-Fe nanocomposite convenient for practical use.Compared to MIL-101-Fe,GA/MIL-101-Fe as catalyst demonstrates much higher reactivity in Fenton-like reaction,attributing to smaller MIL-101-Fe particle size,presence of active Fe(II)sites,and abundant defects in GA.Strikingly,the weakly hydrophobic nature of the composite greatly inhibits the loss of catalytic reactivity after being stored in humid air and accelerates the recovery of reactivity in mild temperature,by resisting the entrance of water molecules and helping to exclude water molecules.This work demonstrates that a delicate design of nanocomposite structure could not only improve the reactivity of the catalytic component,but also overcome its intrinsic drawback by taking advantage of the properties of host.We hope this functional nanoconfinement strategy could be extended to more scenarios in other fields.
基金Vinegar Technologies LLC,Chevron Energy Technology Company,Rice University Consortium for Processes in Porous Media,and the American Chemical Society Petroleum Research Fund(No.ACS PRF 58859-ND6)for their financial support。
文摘The characterization of kerogen nanopores is crucial for predicting the geostorage capacity and recoverability of natural gas in unconventional gas shale reservoirs.Towards this end,a powerful technique is presented which integrates 2D NMR T_(1)-T_(2) relaxation measurements with molecular dynamics(MD)simulations of hydrocarbons confined in the nanopores of kerogen.The integrated NMR-MD technique is demonstrated using T_(1)-T_(2) measurements of kerogen isolates and organic-rich chalks saturated with heptane,together with MD simulations of heptane completely dissolved in a realistic kerogen model.The NMR-MD results are used to extract the swelling ratio and nanopore size distribution of kerogen as a function of depth in the reservoir.The effects of organic nanoconfinement on the T_(1) relaxation dispersion and T_(2) residual dipolar coupling of heptane are investigated,as well as the effect of downhole effective stress on the kerogen nanopore size as a function of depth and compaction.Potential applications in partially depleted gas shale reservoirs are discussed,including CO_(2) utilization/geostorage,geostorage of green H_(2),and integration of the NMR-MD technique with thermodynamic models for predicting the competitive sorption of gas mixtures in kerogen.
基金supported by the National Natural Science Foundation of China(No.62004143)the Key Research and Development Program of Gansu Province-Industrial Project under Grant(No.25YFGA058)+4 种基金the Key Talent Project Foundation of Gansu Province(No.2025RCXM066)the Gansu Provincial Department of Education:Industrial Support Plan Project(No.2025CYZC-005)the Key R&D Program of Hubei Province(No.2022BAA084)the Science and Technology Project of Lanzhou(No.2024-3-42)the Fundamental Research Funds for the Central Universities(No.331920240059)。
文摘Available online Further oxidation of NH3produced via photocatalytic N_(2)fixation represents a promising strategy to enhance the economic value of N_(2)fixation.This work employs first-principles density functional theory(DFT)calculations to demonstrate that incorporating Co into Ni O improves both N_(2)adsorption and activation as well as M-N electron exchange intensity.Guided by these predictions,a novel Co single-atom photocatalyst supported by nanoconfined Ni O@C nanosheets was synthesized using a direct metal atomization method,achieving high HNO_(3)production(60.54%).NH_(4)^(+)and NO_(3)^(-)production rates during N_(2)photofixation reached 67.97μmol g_(cat)^(-1)h^(-1)and 104.28μmol g_(cat)^(-1)h^(-1),respectively.The overall N_(2)→NH_(3)→HNO_(3)photofixation pathway was validated through in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and^(15)N isotopic labeling.Mechanistic studies reveal that Co single-atom introduction serves as an electron trap,enhancing photogenerated electron accumulation with a five-fold increase in carrier density compared to Ni O@C,as observed via in-situ X-ray photoelectron spectroscopy(XPS).This synergistic effect between electron traps and N2adsorption/activation sites at Co single-atom centers supports rapid N_(2)reduction kinetics.Additionally,nanoconfined ink-bottle pores in the carbon layer impede NH_(3)desorption,further boosting NO_(3)-production.This work offers a comprehensive approach to optimizing N_(2)photofixation through electron regulation and surface reaction kinetics.
基金the support from the National Natural Science Foundation (No. 52171186)the Science and Technology Commission of Shanghai Municipality under No. 19511108100+1 种基金Shanghai Education Commission “Shuguang” scholar Project (16SG08)the financial support from the Center of Hydrogen Science, Shanghai Jiao Tong University
文摘MgH_(2) has attracted intensive interests as one of the most promising hydrogen storage materials.Nevertheless,the high desorption temperature,sluggish kinetics,and rapid capacity decay hamper its commercial application.Herein,2D TiO_(2) nanosheets with abundant oxygen vacancies are used to fabricate a flower-like MgH_(2)/TiO_(2) heterostructure with enhanced hydrogen storage performances.Particularly,the onset hydrogen desorption temperature of the MgH_(2)/TiO_(2) heterostructure is lowered down to 180℃(295℃ for blank MgH_(2)).The initial desorption rate of MgH_(2)/TiO_(2) reaches 2.116 wt% min^(-1) at 300℃,35 times of the blank MgH_(2) under the same conditions.Moreover,the capacity retention is as high as 98.5% after 100 cycles at 300℃,remarkably higher than those of the previously reported MgH_(2)-TiO_(2) composites.Both in situ HRTEM observations and ex situ XPS analyses confirm that the synergistic effects from multi-valance of Ti species,accelerated electron transportation caused by oxygen vacancies,formation of catalytic Mg-Ti oxides,and stabilized MgH_(2) NPs confined by TiO_(2) nanosheets contribute to the high stability and kinetically accelerated hydrogen storage performances of the composite.The strategy of using 2D substrates with abundant defects to support nano-sized energy storage materials to build heterostructure is therefore promising for the design of high-performance energy materials.
文摘Unveiling the pore-size performance of metal organic frameworks(MOFs)is imperative for controllable design of sophisticated catalysts.Herein,UiO-66 with distinct macropores and mesopores were intentionally created and served as substrates to create advanced CdS/UiO-66 catalysts.The pore size impacted the spatial distribution of CdS nanoparticles(NPs):CdS tended to deposit on the external surface of mesoporous UiO-66,but spontaneously penetrated into the large cavity of macroporous UiO-66 nanocage.Normalized to unit amount of CdS,the photocatalytic reaction constant of macroporous CdS/UiO-66 over 4-nitroaniline reduction was~3 folds of that of mesoporous counterpart,and outperformed many other reported state-of-art CdS-based catalysts.A confinement effect of CdS NPs within UiO-66 cage could respond for its high activity,which could shorten the electron-transport distance of NPs-MOFs-reactant,and protect the active CdS NPs from photocorrosion.The finding here provides a straightforward paradigm and mechanism to rationally fabricate advance NPs/MOFs for diverse applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.52162012,52262014,22368019)Key Research and Development Project of Hainan Province(Grant Nos.ZDYF2022SHFZ053,ZDYF2021GXJS209)+1 种基金Science and Technology Innovation Talent Platform Fund for South China Sea New Star of Hainan Province(Grant No.NHXXRCXM202305)Open Research Project of State Key Laboratory of Marine Resource Utilization in South China Sea(Grant No.MRUKF2023020).
文摘Water scarcity is a global challenge,and solar evaporation technology offers a promising and eco-friendly solution for freshwater production.Photothermal conversion materials(PCMs)are crucial for solar evaporation.Improving photothermal conversion efficiency and reducing water evaporation enthalpy are the two key strategies for the designing of PCMs.The desired PCMs that combine both of these properties remain a challenging task,even with the latest advancements in the field.Herein,we developed copper nanoparticles(NPs)with different conjugated nitrogen-doped microporous carbon coatings(Cu@C–N)as PCMs.The microporous carbon enveloping layer provides a highly efficient pathway for water transport and a nanoconfined environment that protects Cu NPs and facilitates the evaporation of water clusters,reducing the enthalpy of water evaporation.Meanwhile,the conjugated nitrogen nodes form strong metal-organic coordination bonds with the surface of copper NPs,acting as an energy bridge to achieve rapid energy transfer and provide high solar-to-vapor conversion efficiency.The Cu@C–N exhibited up to 89.4%solar-to-vapor conversion efficiency and an evaporation rate of 1.94 kgm^(−2) h^(−1) under one sun irradiation,outperforming conventional PCMs,including carbon-based materials and semiconductor materials.These findings offer an efficient design scheme for high-performance PCMs essential for solar evaporators to address global water scarcity.
基金the financial support from the National Natural Science Foundation of China(51878332,21976084,and 21925602)the Fundamental Research Funds for the Central Universities.
基金the funding support from the National Natural Science Foundation of China(T2325012 and 52161135104)the Program for HUST Academic Frontier Youth Team.
文摘In molecular modeling of electrical double layers(EDLs),the constant charge method(CCM)is prized for its computational efficiency but cannot maintain electrode equipotentiality like the more resourceintensive constant potential method(CPM),potentially leading to inaccuracies.In certain scenarios,CCM can yield results identical to CPM.However,there are no clear guidelines to determine when CCM is sufficient and when CPM is required.Here,we conduct a series of molecular simulations across various electrodes and electrolytes to present a comprehensive comparison between CCM and CPM under different charging modes.Results reveal that CCM approximates CPM effectively in capturing equilibrium EDL and current-driven dynamics in open electrode systems featuring ionic liquids or regular concentration aqueous electrolytes,while CPM is indispensable in scenarios involving organic and highly concentrated aqueous electrolytes,nanoconfinement effects,and voltage-driven dynamics.This work helps to select appropriate methods for modeling EDL systems,prioritizing accuracy while considering computationalefficiency.
基金supported by the National Science Foundation of China(21878144,21838004 and 21776123)the Foundation for Innovative Research Groups of the National Natural Science Foun-dation of China(21921006).
文摘Ca^(2+)/Na+separation is a common problem in industrial applications,biological and medical fields.However,Ca^(2+)and Na+have similar ionic radii and hydration radii,thus Ca^(2+)/Na+separation is challenging.Inspired by biological channels,group modification is one of the effective methods to improve the separation performance.In this work,molecular dynamics simulations were performed to investigate the effects of different functional groups(COO,NH3+)on the separation performance of Ca^(2+)and Na+through graphene nanopores under an electric field.The pristine graphene nanopore was used for comparison.Results showed that three types of nanopores preferred Ca^(2+)to Na+,and Ca^(2+)/Na+selectivity followed the order of GE-COO(4.06)>GE(1.85)>GE-NH3+(1.63).Detailed analysis of ionic hydration microstructure shows that different nanopores result in different hydration factors for the second hydration layer of Ca^(2+)and the first layer of Na+.Such different hydration factors corresponding to the dehydration ability can effectively evaluate the separation performance.In addition,the breaking of hydrogen bonds between water molecules due to electrostatic effects can directly affect the dehydration ability.Therefore,the electrostatic effect generated by group modification will affect the ionic hydration microstructure,thus reflecting the differences in dehydration ability.This in turn affects the permeable and separation performance of cations.The results of this work provide perceptive guidelines for the application of graphene-based membranes in ion separation.
