The electrical conductivity of minerals under extreme conditions is governed by their variations in composition and structure.Constitution water,which is present in various polymorphic phases of olivine,can significan...The electrical conductivity of minerals under extreme conditions is governed by their variations in composition and structure.Constitution water,which is present in various polymorphic phases of olivine,can significantly enhance electrical conductivity under mantle pressure-temperature conditions,therefore playing a key role in proton transport.Despite this,the conductive mechanisms in hydrous olivine,particularly in hydrous ringwoodite,and the dynamic behavior of hydrogen at elevated temperatures,remain poorly understood.In this study,we investigated the proton conduction mechanisms in hydrous ringwoodite through first-principles calculations.Several hydrous models were considered,and ab initio molecular dynamics(AIMD)simulations were employed to simulate hydrous configurations at high temperatures.Calculations based on density functional perturbation theory(DFPT)and vibrational density of states(VDOS)analyses were conducted to probe the stability of hydrous structures,and investigate the dynamic behavior of internal hydrogen.Our results indicate that hydrogen trapped in Mg^(2+)and Fe^(3+)defects exhibits significantly higher mobility than hydrogen trapped in Si^(4+)defects.At elevated temperatures,we observed the ionization of hydrogen from cationic defects,leading to high and highly anisotropic proton conductivity along the[100]crystallographic direction.This thermal ionization-induced anisotropic conductivity is consistent with experimental observations of olivine single crystals.Finally,the conductivity of the 0.79 wt%hydrous ringwoodite structure was found to range from 10^(-0.3)to 10^(0.4)S/m,the 1.19 wt%structure ranged from 10^(0.4)to 10^(0.9)S/m in the transition region,and the 1.62 wt%structure exhibited conductivity ranging from 10^(0.7)to 10^(1.2)S/m.These results are in excellent agreement with prior experimental data,providing further insight into the proton conduction mechanisms of hydrous olivine under extreme mantle conditions.展开更多
With several favorable properties,including flexibility,biocompatibility,and conductivity,conductive hydrogels are one of the most promising flexible sensing materials and are expected to be used in areas such as wear...With several favorable properties,including flexibility,biocompatibility,and conductivity,conductive hydrogels are one of the most promising flexible sensing materials and are expected to be used in areas such as wearable devices,health monitoring,and electronic skin.However,water in hydrogels freezes at sub-zero temperatures,which greatly affects the performance of hydrogels at low temperatures.Therefore,it remains a challenge to prepare conductive hydrogels that can maintain their performance at low temperatures.In this work,we developed a series of polyoxometalate-based anti-freezing hydrogels with high conductivity by constructing a semi-interpenetrating network using polyacrylamide and sodium alginate,and then introducing H_(3)PW_(12)O_(40)(HPW)and glycerol into it via a facile soaking strategy.Among the obtained anti-freezing hydrogels,PSWG-50%hydrogel has the proton conductivity of 0.325 S·cm^(−1) at room temperature and can maintain high proton conductivity over a wide temperature range from−20 to 65℃.Based on these advantages,PSWG-50%hydrogel has been used in flexible sensors to monitor human movement,such as limb bending.Whether in mild or cold environments,PSWG-50%hydrogel shows great potential in the field of flexible sensor.展开更多
Molecules with multifunctional properties are of immense interest in hybrid materials, while challenges still existed because of the limited compatibility of multiple functionalities in a single system. In this work, ...Molecules with multifunctional properties are of immense interest in hybrid materials, while challenges still existed because of the limited compatibility of multiple functionalities in a single system. In this work, a series of metal-organic complexes were synthesized and characterized under the assembly of electron donor phosphonate, electron acceptor polypyridine ligand and spin carrier rare earth ions. All the compounds exhibited remarkable and reversible responses with photochromism and photomodulated fluorescence, originated from photogenerated radicals via electron transfer from phosphonates to polypyridine ligands. For the Dy analog, slow magnetic relaxation was observed at cryogenic temperature, indicating the single-molecule magnetic behavior. Furthermore, photogenerated radicals could enhance the proton conductive behavior, with about 2 times larger in magnitude after light irradiation for Dy and Y compounds. The introduction of photoluminescence, magnetism and proton conduction into metallic phosphonates can provide potential applications for photochromic materials.展开更多
The dynamic properties of proton conductivity along hydrogen-bonded molecular systems, for example, ice crystal, with structure disorder or damping and finite temperatures exposed in an externally applied electric-fie...The dynamic properties of proton conductivity along hydrogen-bonded molecular systems, for example, ice crystal, with structure disorder or damping and finite temperatures exposed in an externally applied electric-field have been numerically studied by Runge-Kutta way in our soliton model. The results obtained show that the proton-soliton is very robust against the structure disorder including the fluctuation of the force constant and disorder in the sequence of masses and thermal perturbation and damping of medium, the velocity of its conductivity increases with increasing of the externally applied electric-field and decreasing of the damping coefficient of medium, but the proton-soliton disperses for quite great fluctuation of the ＂force constant and damping coefficient. In the numerical simulation we find that the proton-soliton in our model is thermally stable in a large region of temperature of T ≤ 273 K under influences of damping and externally applied electric-field in ice crvstal. This shows that our model is available and appropriate to ice.展开更多
High-performance proton exchange membranes are of great importance for fuel cells.Here,we have synthesized polycarboxylate plasticizer modified MIL-101-Cr-NH_(2)(PCP-MCN),a kind of hybrid metal-organic framework,which ...High-performance proton exchange membranes are of great importance for fuel cells.Here,we have synthesized polycarboxylate plasticizer modified MIL-101-Cr-NH_(2)(PCP-MCN),a kind of hybrid metal-organic framework,which exhibits a superior proton conductivity.PCP-MCN nanoparticles are used as additives to fabricate PCP-MCN/Nafion composite membranes.Microstructures and characteristics of PCP-MCN and these membranes have been extensively investigated.Significant enhancement in proton conduction for PCP-MCN around 55℃ is interestingly found due to the thermal motion of the PCP molecular chains.Robust mechanical properties and higher thermal decomposition temperature of the composite membranes are directly ascribed to strong intermolecular interactions between PCP-MCN and Nafion side chains,i.e.,the formation of substantial acid–base pairs(-SO_(3)^(-)…^(+)H–NH-),which further improves compatibility between additive and Nafion matrix.At the same humidity and temperature condition,the water uptake of composite membranes significantly increases due to the incorporation of porous additives with abundant functional groups and thus less crystallinity degree in comparison to pristine Nafion.Proton conductivity(σ)over wide ranges of humidities(30-100%RH at 25℃)and temperatures(30-98℃ at 100%RH)for prepared membranes is measured.The s in PCPMCN/Nafion composite membranes is remarkably enhanced,i.e.0.245 S/cm for PCP-MCN-3wt.%/Nafion is twice that of Nafion membrane at 98℃ and 100%RH,because of the establishment of well-interconnected proton transport ionic water channels and perhaps faster protonation–deprotonation processes.The composite membranes possess weak humidity-dependence of proton transport and higher water uptake due to excellent water retention ability of PCP-MCN.In particular,when 3 wt.%PCP-MCN was added to Nafion,the power density of a single-cell fabricated with this composite membrane reaches impressively 0.480,1.098 W/cm^(2) under 40%RH,100%RH at 60℃,respectively,guaranteeing it to be a promising proton exchange membrane.展开更多
Graphene oxide(GO)filler containing diversified Nafion-based proton exchange membrane(PEM)is studied to know the unique physical and chemical properties and performances of PEM.Nafion-SPEEK 1%-GO 0.75%(NSG-0.75%)compo...Graphene oxide(GO)filler containing diversified Nafion-based proton exchange membrane(PEM)is studied to know the unique physical and chemical properties and performances of PEM.Nafion-SPEEK 1%-GO 0.75%(NSG-0.75%)composite shows the highest proton conductivity of 0.327 S·cm^(-1) at 90℃ and 100%RH(relative humidity)among all the PEM investigated.The descending order of significant proton conductivity is found as;Nafion-sPGO(1%)0.306 S·cm^(-1)>Nafion/ZIF-8@GO 0.280 S·cm^(-1)>Nafion/PGO(2%)0.277 S·cm^(-1)>Nafion/GO-sulfur(3%)0.232 S·cm^(-1)>Nafion/GO-poly-SPM-co-PEGMEMA(1%)0.229 S·cm^(-1)>Nafion/Ce-sPGO(1%)0.215 S·cm^(-1).The proton conductivity,water uptake capacity and ion exchange capacity,hydration number,thermal and oxidative stability,mechanical integrity(tensile strength),maximum power,and current density are found to be increased while activation energy and fuel crossover show a decrement as GO or modified GO is incorporated in the Nafion matrix.Principal component analysis(PCA)predicted a significant correlation between the proton conductivity and the properties;the water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density are 0.598%,0.688%,0.894%,0.980%,and 0.852%accordingly.A multiple linear model equation of proton conductivity is defined with the parameters of water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density whereas the regression coefficient is 0.9923.展开更多
Two primitive metal-organic frameworks(MOFs),Ni L1 and Ni L2,based on Ni_(8)O_(6)-cluster and ditopic pyrazolate linkers,L1(with rigid alkyne arms)and L2(with flexible alkyne chains),were prepared.The proton conductiv...Two primitive metal-organic frameworks(MOFs),Ni L1 and Ni L2,based on Ni_(8)O_(6)-cluster and ditopic pyrazolate linkers,L1(with rigid alkyne arms)and L2(with flexible alkyne chains),were prepared.The proton conductivities of these MOFs in pristine form and imidazole-encapsulated forms,Im@Ni L1 and Im@Ni L2,were measured and compared.Upon introduction of imidazole molecules,the proton conductivity could be increased by 3 to 5 orders of magnitude and reached as high as 1.72×10^(-2)S/cm(at 98%RH and 80℃).Also,whether imidazole molecules were introduced or not,Ni_(8)O_(6)-based MOFs with L2 in general gave better proton conductivity than those with L1 signifying that flexible side arms indeed assist proton conduction probably via establishment of efficient proton-conducting channels along with formation of highly ordered domains of water/imidazole molecules within the network cavities.Beyond the active Ni_(8)O_(6)-cluster,tuning flexibility of linker pendants serves as an alternative approach to regulate/modulate the proton conductivity of MOFs.展开更多
Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthe...Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthesized and structurally characterized.Single-crystal X-ray diffraction analyses reveal that the polyanions of La_(6)Co_(2)and La_(6)Mn_(2)consist of the uncommon 3d-4f-5d clusters{La_(6)W_(12)Co_(2)}and{La_(6)W_(12)Mn_(2)},which are encapsulated by four trilacunary Keggin tungstoantimonates to form the parallelogram-shaped title compounds.Additionally,the polyanions can be extended into a two-dimensional(2D)frame by the linkage of peripheral Na+ions.The inner space of the 2D layer was filled with water molecules and thus an H-bonded network was formed,which is expected to exhibit a fascinating proton conductivity.The study of water-assisted proton conduction demonstrated that La_(6)Co_(2)and La_(6)Mn_(2)were temperature-and humiditydependent proton conductors,respectively,and the proton conductivities could reach 1.3×10^(-2)and 2.3×10^(-2)S/cm at 65℃and 90%RH conditions.展开更多
Herein,we developed for the first time two carboxylic acid based intrinsic proton conductors(COOHCOF-1 and COOH-COF-2)via pre-assembly approach.The obtained COOH-COF-1 and COOH-COF-2 not only show outstanding chemical...Herein,we developed for the first time two carboxylic acid based intrinsic proton conductors(COOHCOF-1 and COOH-COF-2)via pre-assembly approach.The obtained COOH-COF-1 and COOH-COF-2 not only show outstanding chemical and thermal stabilities,but also exhibit superhigh intrinsic proton conductive behaviors.Especially,the intrinsic proton conductivity of COOH-COF-2 is up to 2.6×10^(−3) S/cm at 353 K and 98%RH,which is the highest value among all the reported acid functionalized COFs.This work lights up the way for the rational design of functional COFs with remarkably intrinsic proton conducting performance and related practical applications.展开更多
A γ - type of layered zirconium hydrogen phosphate, Zr(HPO 4) 2·2H 2O( γ ZrP), was synthesized under hydrothermal conditions and characterized by powder X ray diffraction and thermogravimetric analysis....A γ - type of layered zirconium hydrogen phosphate, Zr(HPO 4) 2·2H 2O( γ ZrP), was synthesized under hydrothermal conditions and characterized by powder X ray diffraction and thermogravimetric analysis. The temperature dependence of the proton conductivity in γ ZrP was investigated in a temperature range of 23￣413 ℃ by ac impedance spectroscopy. The variation of the conductivity with water loss and phase transitions was observed. The best proton conductivity in γ ZrP is 6×10 -4 S·cm -1 at 60 ℃. The proton conductivities in the dehydrated sample are ￣10 -5 at 150 ℃ and ￣10 -4 S·cm -1 at 350 ℃, respectively. The conductivities as a function of humidity in the temperature range of 120￣200 ℃ were measured.展开更多
A heterometal-organic framework {[Pr2Ca（betc）2（H2O）7]·H2O}n（1） was prepared by the hydrothermal reaction of 1,2,4,5-benzenetetracarboxylic acid（H4betc） with Pr（NO3）3 and CaCO3, and further characterized...A heterometal-organic framework {[Pr2Ca（betc）2（H2O）7]·H2O}n（1） was prepared by the hydrothermal reaction of 1,2,4,5-benzenetetracarboxylic acid（H4betc） with Pr（NO3）3 and CaCO3, and further characterized by single-crystal X-ray structural analysis, elemental analysis, IR, thermal gravimetric, and X-ray powder diffraction. Complex 1 crystallizes in triclinic, space group P1 with a = 7.3668（12）, b = 10.1726（14）, c = 11.2264（15） A, a = 100.404（2）, b = 106.113（3）, g = 109.158（3）o, V = 728.48（19） A3, Mr = 966.26, Z = 1, F（000） = 470, Dc = 2.203 g/cm3, m（Mo Kα） = 3.585 mm-1, the final R = 0.0195 and w R = 0.0470（I 〉 2s（I））. Complex 1 is a 3D network with pcu topology with 1D porosity and rich hydrogen-bonding interactions. The proton conductivity of complex 1 was also studied under ~97% relative humidity and the different temperature conditions.展开更多
Highly proton-conductive metal-organic coordination polymers(MOCPs)have attracted a great deal of attention because of their potential applications in proton exchange membrane fuel cells and electrochemical sensors.Cu...Highly proton-conductive metal-organic coordination polymers(MOCPs)have attracted a great deal of attention because of their potential applications in proton exchange membrane fuel cells and electrochemical sensors.Currently,the precise control of proton conductivity is mainly achieved through the rational design of organic ligands and the effective modification of pore structures.In contrast,little attention has been paid to the influence of metal ions of MOCPs on their proton conductivities due to the absence of isostructural compounds for comparison and analysis.Herein,we designed three MOCPs{[(H_(3)O^(+))_(2)][Zn(pzdc)_(2)]}_(n),{[(H_(3)O^(+))_(2)][Mn(pzdc)_(2)]}_(n)and[Cu(Hpzdc)_(2)·2H_(2)O]n(H_(2)pzdc=2,3-pyrazinedicarboxylic acid)with very similar chemical formulae and single-crystal structures as models to investigate how the coordination interactions/abilities of metal ions affect their proton conductivities and water stabilities.Remarkably,these three MOCPs show proton conductivities as high as 10^(-3)S cm^(-1)at 323 K and∼97%RH along with excellent stabilities to temperature,water,acid and base(over a broad pH range of 0-12).Density functional theory(DFT)calculations show that the binding energies of the O-H bonds of the carboxyl groups in the solvation models are a predominant factor in precisely tuning the proton conductivity at∼97%RH.Furthermore,the extraordinary stabilities,especially in water,are more likely to be associated with the coordination interactions resulting in a significant decrease in the system energies of the generated coordination compounds.These results provide a novel perspective for the design and synthesis of MOCPs with high proton conductivity and good stability.展开更多
A new Zr(IV)-based metal–organic framework,termed VNU-17[Zr_(6)O_(8)(H_(2)O)_(8)(HSNDC)_(4),where HSNDC^(2−)=4-sulfonaphthalene-2,6-dicarboxylate],was designed to enhance proton conductivity through the incorporation...A new Zr(IV)-based metal–organic framework,termed VNU-17[Zr_(6)O_(8)(H_(2)O)_(8)(HSNDC)_(4),where HSNDC^(2−)=4-sulfonaphthalene-2,6-dicarboxylate],was designed to enhance proton conductivity through the incorporation of Brønsted acid functionalities.The resulting VNU-17 framework adopted the bcu topology and the structure was highlighted by densely packed sulfonic acid groups lining 6Åchannels.Following this,the internal void space of VNU-17 was engineered to further enhance proton conductivity.展开更多
It is a widely held view that the continuous hydrogen bonding network plays a crucial role in proton transport.Herein,we report the cyclic single-crystal-to-single-crystal transformation of three hydrogenbonded organi...It is a widely held view that the continuous hydrogen bonding network plays a crucial role in proton transport.Herein,we report the cyclic single-crystal-to-single-crystal transformation of three hydrogenbonded organic frameworks(HOFs),BPPA,BPPA-azo,and BPPA-gua,induced by the change of auxiliary ligands,which explicitly demonstrates that the hydrophilic interlayers of BPPA possess good self-adaptability to vip molecules.Their proton conducting performance was studied under different humidities at varying temperatures,indicating that the proton conductivity of BPPA with continuous hydrogen bonding networks formed by water molecules reaches 5.14×10^(−2)S cm^(−1) under 80℃ and 95% relative humidity(RH),which is four orders of magnitude higher than those of BPPA-azo and BPPA-gua with their continuous hydrogen bonding networks formed by 1,2,4-triazole and guanidine molecules,respectively,under the same conditions.The evidence from this study suggests that the rotational degrees of freedom of hydrogen bonding donors and acceptors play the most important role in the construction of efficient proton conduction pathways.展开更多
Polyethyleneimine (PEI) is expected to become a new type of proton conduction booster due to its high density amine and extremely high flexibility.Herein,a nanofiber membrane (eHPW-PEI) composed of PEI and phosphotung...Polyethyleneimine (PEI) is expected to become a new type of proton conduction booster due to its high density amine and extremely high flexibility.Herein,a nanofiber membrane (eHPW-PEI) composed of PEI and phosphotungstic acid (H_(3)PW_(12)O_(40),HPW) was prepared by electrostatic spinning using polyvinylpyrrolidone (PVP) as an adhesive.In eHPW-PEI,the continuous H-bond network formed by HPW-PEI acid–base pairs,the segmental movement of highly flexible PEI and the well-tuned pathway of 1D nanofibers jointly prompt the fast transfer of protons under high temperature and low humidity conditions.The proton conductivity of eHPW-PEI with 25 wt% HPW (eHPW-PEI1) reached 1.6×10^(-3) S cm^(-1) at 85℃ and 60% relative humidity (RH) and 3.7×10^(-3) S cm^(-1) at 135℃.This is the first time that the segmental movement of a highly flexible polymer is utilized to accelerate proton transfer,which may be considered as a ‘proton escalator’.展开更多
Exploitation of stable proton conducting materials with high stability and excellent conductivity is becom-ing more important but challenging.Herein,two novel porous transition metal-organic frameworks(MOFs),formulate...Exploitation of stable proton conducting materials with high stability and excellent conductivity is becom-ing more important but challenging.Herein,two novel porous transition metal-organic frameworks(MOFs),formulated as[Zn(btzip)(H_(2)O)]·H_(2)O(LCUH-107)and[Ni(btzip)(H_(2)btzip)]·4H_(2)O(LCUH-108),are successfully synthesized.LCUH-107 and LCUH-108 exhibit excellent thermal and chemical stabilities.LCUH-108 has a suitable pore size(8.36Å×5.74Å)to load trifluoroacetic acid(TFA,5.72Å×5.65Å×5.06Å),which is larger than that of LCUH-107(3.50Å×2.04Å).Therefore,TFA molecules can be loaded into the pores of LCUH-108 while they were only loaded onto the surface of LCUH-107.Both TFA/LCUH-107(2.95×10^(-2)S cm^(−1))and TFA@LCUH-108(2.05×10^(-1)S cm^(−1))exhibit excellent proton con-duction at 80℃and 100%relative humidity(RH);in particular,the proton conductivity value of TFA@LCUH-108 can be as high as 10-1 S cm^(−1),which might be due to the fact that TFA molecules can be confined into their suitable pores and finally form strong continuous and stable hydrogen-bonding networks.The TFA molecules loaded into the suitable pores of LCUH-108 play a key role in improving greatly the proton conductivity of LCUH-108,while TFA molecules loaded onto the surface of LCUH-107 can only slightly improve the proton conductivity of LCUH-107,which can be confirmed by various con-trast tests and simulated calculations.This work gives a novel strategy to design efficient artificial crystal-line catalysts for proton conduction.展开更多
A family of isostructural heterometallic MOFs based on Fe_(2)M clusters(MOF-Fe_(2)M;M=Fe,Co and Ni,respectively)have been synthesized and serve as potential proton conductors and photocatalysts for CO_(2)photoreductio...A family of isostructural heterometallic MOFs based on Fe_(2)M clusters(MOF-Fe_(2)M;M=Fe,Co and Ni,respectively)have been synthesized and serve as potential proton conductors and photocatalysts for CO_(2)photoreduction,exhibiting varied proton conductivities and photocatalytic performances.展开更多
The development of new proton-conducting materials that are cost effective and have high proton conductivity and water stability is very important in fuel cell technology.Lanthanide-based metal-organic frameworks(MOFs...The development of new proton-conducting materials that are cost effective and have high proton conductivity and water stability is very important in fuel cell technology.Lanthanide-based metal-organic frameworks(MOFs)exhibit proton conduction properties but usually display the problem of poor hydrophilicity.We propose that the organic ligands can be replaced with polyoxometalates,and the as-prepared lanthanide-based inorganic porous materials with lanthanide ions may possess improved hydrophilicity and proton conductivity.Herein,we re-synthesize two inorganic open frameworks based on[MnV_(13)O_(38)]^(7-)clusters and lanthanide ions(H[Ln(H_(2)O)_(2)]2[MnV_(13)O_(38)]·9NMP·17H_(2)O(Ln=Ce(1),and La(2);NMP=N-methyl-2-pyrrolidone))and explore their potential proton conductivities.Under the same test conditions,both compounds show only a little difference in proton conductivities with the values of 4.68×10^(-3)S cm^(-1)and 3.46×10^(-3)S cm^(-1)at 61℃,respectively,which are much higher than those of the previously reported proton-conducting materials based on lanthanide metal ions.In addition,we also prove their proton-conducting nature by measuring the electron resistance via the Hebb-Wagner polarization technique and proton conduction via the D_(2)O-exchange test.The 3D channel in the two compounds plays a key role in constructing an efficient proton transfer pathway via a hydrogen bonding network.展开更多
Ceramic proton conductors are promising materials for clean energy.In contrast to the conventional acceptor doping,donor doping into the oxides with intrinsic oxygen vacancies is a novel strategy to achieve the reduce...Ceramic proton conductors are promising materials for clean energy.In contrast to the conventional acceptor doping,donor doping into the oxides with intrinsic oxygen vacancies is a novel strategy to achieve the reduced proton trapping.Here,we report high proton conductivity(e.g.,0.01 S cm^(-1) at 320℃)and high chemical stability of pentavalent donor doped BaScO_(2.5),BaSc_(0.75)Nb_(0.25)O_(2.75).The high proton conductivity is attributable to high proton concentration and high proton diffusion coefficient.The high proton concentration is ascribed to a large amount of oxygen vacancies in BaSc_(0.75)Nb_(0.25)O_(2.75) and full hydration in hydrated BaSc_(0.75)Nb_(0.25)O_(2.75).The high proton diffusion coefficient is attributable to its low activation energy,suggesting reduced proton trapping due to the repulsion between the donor Nb^(5+)dopant and protons.The repulsion is clearly shown by the ab initio molecular dynamics simulations.展开更多
Porous crystalline metal–organic frameworks (MOFs) bearing sulfonic groups (–SO_(3)H) are receiving increasing attention as solid-state proton conductors because the –SO_(3)H group can not only enhance the proton c...Porous crystalline metal–organic frameworks (MOFs) bearing sulfonic groups (–SO_(3)H) are receiving increasing attention as solid-state proton conductors because the –SO_(3)H group can not only enhance the proton concentration, but also form hydrogen bonding networks for high proton conductivity. A large number of 1,4-phenyldicarboxylic acids or biphenyldicarboxylic acids bearing two –SO_(3)H groups have been applied for the synthesis of proton-conducting MOFs. Surprisingly, 4,4′-biphenyldicarboxylic acid bearing one –SO_(3)H group has never been explored for the construction of proton-conducting materials. Herein, we first designed and synthesized 2-sulfonyl-4,4′-biphenyldicarboxylic acid (H_(3)L). By applying this ligand to react with lanthanide salts, a series of three-dimensional MOFs, (Me_(2)NH_(2))_(2)(H_(3)O)[LnL_(2)]·8H_(2)O (Ln=Eu (1), Gd (2), Tb (3)) have been prepared. Due to the presence of the uncoordinated –SO_(3)H group and the encapsulation of high concentrations of dimethylammonium and hydronium cations in the cavity, the MOFs 1–3 show a high proton conductivity (8.83 × 10^(-3) S cm^(-1)) at 95℃ and 60% relative humidity (RH). More importantly, this high proton conductivity can be maintained over 72 hours without any significant decrease at low RH.展开更多
基金supported by the National Natural Science Foundation of China(41930112,91755215)the Sichuan Students'Innovation and entrepreneurship training program(s202310616086).
文摘The electrical conductivity of minerals under extreme conditions is governed by their variations in composition and structure.Constitution water,which is present in various polymorphic phases of olivine,can significantly enhance electrical conductivity under mantle pressure-temperature conditions,therefore playing a key role in proton transport.Despite this,the conductive mechanisms in hydrous olivine,particularly in hydrous ringwoodite,and the dynamic behavior of hydrogen at elevated temperatures,remain poorly understood.In this study,we investigated the proton conduction mechanisms in hydrous ringwoodite through first-principles calculations.Several hydrous models were considered,and ab initio molecular dynamics(AIMD)simulations were employed to simulate hydrous configurations at high temperatures.Calculations based on density functional perturbation theory(DFPT)and vibrational density of states(VDOS)analyses were conducted to probe the stability of hydrous structures,and investigate the dynamic behavior of internal hydrogen.Our results indicate that hydrogen trapped in Mg^(2+)and Fe^(3+)defects exhibits significantly higher mobility than hydrogen trapped in Si^(4+)defects.At elevated temperatures,we observed the ionization of hydrogen from cationic defects,leading to high and highly anisotropic proton conductivity along the[100]crystallographic direction.This thermal ionization-induced anisotropic conductivity is consistent with experimental observations of olivine single crystals.Finally,the conductivity of the 0.79 wt%hydrous ringwoodite structure was found to range from 10^(-0.3)to 10^(0.4)S/m,the 1.19 wt%structure ranged from 10^(0.4)to 10^(0.9)S/m in the transition region,and the 1.62 wt%structure exhibited conductivity ranging from 10^(0.7)to 10^(1.2)S/m.These results are in excellent agreement with prior experimental data,providing further insight into the proton conduction mechanisms of hydrous olivine under extreme mantle conditions.
基金supported by the National Natural Science Foundation of China(22071019,21872021 and 21671033).
文摘With several favorable properties,including flexibility,biocompatibility,and conductivity,conductive hydrogels are one of the most promising flexible sensing materials and are expected to be used in areas such as wearable devices,health monitoring,and electronic skin.However,water in hydrogels freezes at sub-zero temperatures,which greatly affects the performance of hydrogels at low temperatures.Therefore,it remains a challenge to prepare conductive hydrogels that can maintain their performance at low temperatures.In this work,we developed a series of polyoxometalate-based anti-freezing hydrogels with high conductivity by constructing a semi-interpenetrating network using polyacrylamide and sodium alginate,and then introducing H_(3)PW_(12)O_(40)(HPW)and glycerol into it via a facile soaking strategy.Among the obtained anti-freezing hydrogels,PSWG-50%hydrogel has the proton conductivity of 0.325 S·cm^(−1) at room temperature and can maintain high proton conductivity over a wide temperature range from−20 to 65℃.Based on these advantages,PSWG-50%hydrogel has been used in flexible sensors to monitor human movement,such as limb bending.Whether in mild or cold environments,PSWG-50%hydrogel shows great potential in the field of flexible sensor.
基金supported by the National Natural Science Foundation of China (Nos. 21901133 and 22071126)Key Research and Development Project of Shandong Province (No. 2019GGX102006)the State Key Laboratory of Fine Chemicals (No. KF1905)。
文摘Molecules with multifunctional properties are of immense interest in hybrid materials, while challenges still existed because of the limited compatibility of multiple functionalities in a single system. In this work, a series of metal-organic complexes were synthesized and characterized under the assembly of electron donor phosphonate, electron acceptor polypyridine ligand and spin carrier rare earth ions. All the compounds exhibited remarkable and reversible responses with photochromism and photomodulated fluorescence, originated from photogenerated radicals via electron transfer from phosphonates to polypyridine ligands. For the Dy analog, slow magnetic relaxation was observed at cryogenic temperature, indicating the single-molecule magnetic behavior. Furthermore, photogenerated radicals could enhance the proton conductive behavior, with about 2 times larger in magnitude after light irradiation for Dy and Y compounds. The introduction of photoluminescence, magnetism and proton conduction into metallic phosphonates can provide potential applications for photochromic materials.
基金The project supported by National Natural Science Foundation of China under Grant No. 90306015
文摘The dynamic properties of proton conductivity along hydrogen-bonded molecular systems, for example, ice crystal, with structure disorder or damping and finite temperatures exposed in an externally applied electric-field have been numerically studied by Runge-Kutta way in our soliton model. The results obtained show that the proton-soliton is very robust against the structure disorder including the fluctuation of the force constant and disorder in the sequence of masses and thermal perturbation and damping of medium, the velocity of its conductivity increases with increasing of the externally applied electric-field and decreasing of the damping coefficient of medium, but the proton-soliton disperses for quite great fluctuation of the ＂force constant and damping coefficient. In the numerical simulation we find that the proton-soliton in our model is thermally stable in a large region of temperature of T ≤ 273 K under influences of damping and externally applied electric-field in ice crvstal. This shows that our model is available and appropriate to ice.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.12075172,12375288,12205089,and 12105048)National Key R&D Program of China(Grant No.2019YFA0210003)Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110817).
文摘High-performance proton exchange membranes are of great importance for fuel cells.Here,we have synthesized polycarboxylate plasticizer modified MIL-101-Cr-NH_(2)(PCP-MCN),a kind of hybrid metal-organic framework,which exhibits a superior proton conductivity.PCP-MCN nanoparticles are used as additives to fabricate PCP-MCN/Nafion composite membranes.Microstructures and characteristics of PCP-MCN and these membranes have been extensively investigated.Significant enhancement in proton conduction for PCP-MCN around 55℃ is interestingly found due to the thermal motion of the PCP molecular chains.Robust mechanical properties and higher thermal decomposition temperature of the composite membranes are directly ascribed to strong intermolecular interactions between PCP-MCN and Nafion side chains,i.e.,the formation of substantial acid–base pairs(-SO_(3)^(-)…^(+)H–NH-),which further improves compatibility between additive and Nafion matrix.At the same humidity and temperature condition,the water uptake of composite membranes significantly increases due to the incorporation of porous additives with abundant functional groups and thus less crystallinity degree in comparison to pristine Nafion.Proton conductivity(σ)over wide ranges of humidities(30-100%RH at 25℃)and temperatures(30-98℃ at 100%RH)for prepared membranes is measured.The s in PCPMCN/Nafion composite membranes is remarkably enhanced,i.e.0.245 S/cm for PCP-MCN-3wt.%/Nafion is twice that of Nafion membrane at 98℃ and 100%RH,because of the establishment of well-interconnected proton transport ionic water channels and perhaps faster protonation–deprotonation processes.The composite membranes possess weak humidity-dependence of proton transport and higher water uptake due to excellent water retention ability of PCP-MCN.In particular,when 3 wt.%PCP-MCN was added to Nafion,the power density of a single-cell fabricated with this composite membrane reaches impressively 0.480,1.098 W/cm^(2) under 40%RH,100%RH at 60℃,respectively,guaranteeing it to be a promising proton exchange membrane.
文摘Graphene oxide(GO)filler containing diversified Nafion-based proton exchange membrane(PEM)is studied to know the unique physical and chemical properties and performances of PEM.Nafion-SPEEK 1%-GO 0.75%(NSG-0.75%)composite shows the highest proton conductivity of 0.327 S·cm^(-1) at 90℃ and 100%RH(relative humidity)among all the PEM investigated.The descending order of significant proton conductivity is found as;Nafion-sPGO(1%)0.306 S·cm^(-1)>Nafion/ZIF-8@GO 0.280 S·cm^(-1)>Nafion/PGO(2%)0.277 S·cm^(-1)>Nafion/GO-sulfur(3%)0.232 S·cm^(-1)>Nafion/GO-poly-SPM-co-PEGMEMA(1%)0.229 S·cm^(-1)>Nafion/Ce-sPGO(1%)0.215 S·cm^(-1).The proton conductivity,water uptake capacity and ion exchange capacity,hydration number,thermal and oxidative stability,mechanical integrity(tensile strength),maximum power,and current density are found to be increased while activation energy and fuel crossover show a decrement as GO or modified GO is incorporated in the Nafion matrix.Principal component analysis(PCA)predicted a significant correlation between the proton conductivity and the properties;the water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density are 0.598%,0.688%,0.894%,0.980%,and 0.852%accordingly.A multiple linear model equation of proton conductivity is defined with the parameters of water uptake capacity,ion exchange capacity,hydration number,maximum power density,and maximum current density whereas the regression coefficient is 0.9923.
基金the National Natural Science Foundation of China(No.21871061)the Foundation of Basic and Applied Basic Research of Guangdong Province(No.2021A1515010274)+2 种基金the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032)the Science and Technology Planning Project of Guangdong Province(No.2021A0505030066)the Science and Technology Program of Guangzhou(No.201807010026)。
文摘Two primitive metal-organic frameworks(MOFs),Ni L1 and Ni L2,based on Ni_(8)O_(6)-cluster and ditopic pyrazolate linkers,L1(with rigid alkyne arms)and L2(with flexible alkyne chains),were prepared.The proton conductivities of these MOFs in pristine form and imidazole-encapsulated forms,Im@Ni L1 and Im@Ni L2,were measured and compared.Upon introduction of imidazole molecules,the proton conductivity could be increased by 3 to 5 orders of magnitude and reached as high as 1.72×10^(-2)S/cm(at 98%RH and 80℃).Also,whether imidazole molecules were introduced or not,Ni_(8)O_(6)-based MOFs with L2 in general gave better proton conductivity than those with L1 signifying that flexible side arms indeed assist proton conduction probably via establishment of efficient proton-conducting channels along with formation of highly ordered domains of water/imidazole molecules within the network cavities.Beyond the active Ni_(8)O_(6)-cluster,tuning flexibility of linker pendants serves as an alternative approach to regulate/modulate the proton conductivity of MOFs.
基金supported by the National Natural Science Foundation of China(No.22071045)the Excellent Youth Science Fund Project of Henan Province(No.202300410042)+2 种基金the Natural Science Foundation of Henan Province(No.232300420372)Henan Universitythe State Key Laboratory of Physical Chemistry of the Solid Surface of Xiamen University。
文摘Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthesized and structurally characterized.Single-crystal X-ray diffraction analyses reveal that the polyanions of La_(6)Co_(2)and La_(6)Mn_(2)consist of the uncommon 3d-4f-5d clusters{La_(6)W_(12)Co_(2)}and{La_(6)W_(12)Mn_(2)},which are encapsulated by four trilacunary Keggin tungstoantimonates to form the parallelogram-shaped title compounds.Additionally,the polyanions can be extended into a two-dimensional(2D)frame by the linkage of peripheral Na+ions.The inner space of the 2D layer was filled with water molecules and thus an H-bonded network was formed,which is expected to exhibit a fascinating proton conductivity.The study of water-assisted proton conduction demonstrated that La_(6)Co_(2)and La_(6)Mn_(2)were temperature-and humiditydependent proton conductors,respectively,and the proton conductivities could reach 1.3×10^(-2)and 2.3×10^(-2)S/cm at 65℃and 90%RH conditions.
基金supported by the National Natural Science Foundation of China(Nos.21978138 and 22035003)the Fundamental Research Funds for the Central Universities(Nankai University)the Haihe Laboratory of Sustainable Chemical Transformations(No.YYJC202101).
文摘Herein,we developed for the first time two carboxylic acid based intrinsic proton conductors(COOHCOF-1 and COOH-COF-2)via pre-assembly approach.The obtained COOH-COF-1 and COOH-COF-2 not only show outstanding chemical and thermal stabilities,but also exhibit superhigh intrinsic proton conductive behaviors.Especially,the intrinsic proton conductivity of COOH-COF-2 is up to 2.6×10^(−3) S/cm at 353 K and 98%RH,which is the highest value among all the reported acid functionalized COFs.This work lights up the way for the rational design of functional COFs with remarkably intrinsic proton conducting performance and related practical applications.
文摘A γ - type of layered zirconium hydrogen phosphate, Zr(HPO 4) 2·2H 2O( γ ZrP), was synthesized under hydrothermal conditions and characterized by powder X ray diffraction and thermogravimetric analysis. The temperature dependence of the proton conductivity in γ ZrP was investigated in a temperature range of 23￣413 ℃ by ac impedance spectroscopy. The variation of the conductivity with water loss and phase transitions was observed. The best proton conductivity in γ ZrP is 6×10 -4 S·cm -1 at 60 ℃. The proton conductivities in the dehydrated sample are ￣10 -5 at 150 ℃ and ￣10 -4 S·cm -1 at 350 ℃, respectively. The conductivities as a function of humidity in the temperature range of 120￣200 ℃ were measured.
基金supported by the National Natural Science Foundation of China(21401147 and 21301134)Basic Research Program of Natural Science from Shaanxi Provincial Government(2015JQ2032)+2 种基金Scientific Research Program from Education Department of Shaanxi Provincial Government(2013JK0654)Opening Foundation from State Key Laboratory of Coordination Chemistry in Nanjing University(201219)the Program for Distinguished Young Scholars of Xi’an Polytechnic University(201403)
文摘A heterometal-organic framework {[Pr2Ca（betc）2（H2O）7]·H2O}n（1） was prepared by the hydrothermal reaction of 1,2,4,5-benzenetetracarboxylic acid（H4betc） with Pr（NO3）3 and CaCO3, and further characterized by single-crystal X-ray structural analysis, elemental analysis, IR, thermal gravimetric, and X-ray powder diffraction. Complex 1 crystallizes in triclinic, space group P1 with a = 7.3668（12）, b = 10.1726（14）, c = 11.2264（15） A, a = 100.404（2）, b = 106.113（3）, g = 109.158（3）o, V = 728.48（19） A3, Mr = 966.26, Z = 1, F（000） = 470, Dc = 2.203 g/cm3, m（Mo Kα） = 3.585 mm-1, the final R = 0.0195 and w R = 0.0470（I 〉 2s（I））. Complex 1 is a 3D network with pcu topology with 1D porosity and rich hydrogen-bonding interactions. The proton conductivity of complex 1 was also studied under ~97% relative humidity and the different temperature conditions.
基金financial support of the National Natural Science Foundation of China(21401147,21403048 and 21771047)the Natural Science Basic Research Plan in the Shaanxi Province of China(2019JM-397)+1 种基金the Special Project of Talent Cultivation in the West Region of China Scholarship Council(201808615077)the Innovation Training Project for College Students in Shaanxi Province of China(S202210709091)。
文摘Highly proton-conductive metal-organic coordination polymers(MOCPs)have attracted a great deal of attention because of their potential applications in proton exchange membrane fuel cells and electrochemical sensors.Currently,the precise control of proton conductivity is mainly achieved through the rational design of organic ligands and the effective modification of pore structures.In contrast,little attention has been paid to the influence of metal ions of MOCPs on their proton conductivities due to the absence of isostructural compounds for comparison and analysis.Herein,we designed three MOCPs{[(H_(3)O^(+))_(2)][Zn(pzdc)_(2)]}_(n),{[(H_(3)O^(+))_(2)][Mn(pzdc)_(2)]}_(n)and[Cu(Hpzdc)_(2)·2H_(2)O]n(H_(2)pzdc=2,3-pyrazinedicarboxylic acid)with very similar chemical formulae and single-crystal structures as models to investigate how the coordination interactions/abilities of metal ions affect their proton conductivities and water stabilities.Remarkably,these three MOCPs show proton conductivities as high as 10^(-3)S cm^(-1)at 323 K and∼97%RH along with excellent stabilities to temperature,water,acid and base(over a broad pH range of 0-12).Density functional theory(DFT)calculations show that the binding energies of the O-H bonds of the carboxyl groups in the solvation models are a predominant factor in precisely tuning the proton conductivity at∼97%RH.Furthermore,the extraordinary stabilities,especially in water,are more likely to be associated with the coordination interactions resulting in a significant decrease in the system energies of the generated coordination compounds.These results provide a novel perspective for the design and synthesis of MOCPs with high proton conductivity and good stability.
基金supported by the U.S.Office of Naval Research Global:Naval International Cooperative Opportunities in Science and Technology Program(No.N62909-16-1-2146).
文摘A new Zr(IV)-based metal–organic framework,termed VNU-17[Zr_(6)O_(8)(H_(2)O)_(8)(HSNDC)_(4),where HSNDC^(2−)=4-sulfonaphthalene-2,6-dicarboxylate],was designed to enhance proton conductivity through the incorporation of Brønsted acid functionalities.The resulting VNU-17 framework adopted the bcu topology and the structure was highlighted by densely packed sulfonic acid groups lining 6Åchannels.Following this,the internal void space of VNU-17 was engineered to further enhance proton conductivity.
基金supported by the National Natural Science Foundation of China(NSFC,Grant No.21771193,22275210,and 22201305)the Fundamental Research Funds for the Central Universities(22CX06024A)the Outstanding Youth Science Fund Projects of Shandong Province(2022HWYQ-070).
文摘It is a widely held view that the continuous hydrogen bonding network plays a crucial role in proton transport.Herein,we report the cyclic single-crystal-to-single-crystal transformation of three hydrogenbonded organic frameworks(HOFs),BPPA,BPPA-azo,and BPPA-gua,induced by the change of auxiliary ligands,which explicitly demonstrates that the hydrophilic interlayers of BPPA possess good self-adaptability to vip molecules.Their proton conducting performance was studied under different humidities at varying temperatures,indicating that the proton conductivity of BPPA with continuous hydrogen bonding networks formed by water molecules reaches 5.14×10^(−2)S cm^(−1) under 80℃ and 95% relative humidity(RH),which is four orders of magnitude higher than those of BPPA-azo and BPPA-gua with their continuous hydrogen bonding networks formed by 1,2,4-triazole and guanidine molecules,respectively,under the same conditions.The evidence from this study suggests that the rotational degrees of freedom of hydrogen bonding donors and acceptors play the most important role in the construction of efficient proton conduction pathways.
基金supported by the National Natural Science Foundation of China(grant no.21671033,22071019 and 21872021)the National Key Research and Development Program of China(grant no.2016YFB0901600)the Zhejiang Provincial Natural Science Foundation of China(LY18B010001).
文摘Polyethyleneimine (PEI) is expected to become a new type of proton conduction booster due to its high density amine and extremely high flexibility.Herein,a nanofiber membrane (eHPW-PEI) composed of PEI and phosphotungstic acid (H_(3)PW_(12)O_(40),HPW) was prepared by electrostatic spinning using polyvinylpyrrolidone (PVP) as an adhesive.In eHPW-PEI,the continuous H-bond network formed by HPW-PEI acid–base pairs,the segmental movement of highly flexible PEI and the well-tuned pathway of 1D nanofibers jointly prompt the fast transfer of protons under high temperature and low humidity conditions.The proton conductivity of eHPW-PEI with 25 wt% HPW (eHPW-PEI1) reached 1.6×10^(-3) S cm^(-1) at 85℃ and 60% relative humidity (RH) and 3.7×10^(-3) S cm^(-1) at 135℃.This is the first time that the segmental movement of a highly flexible polymer is utilized to accelerate proton transfer,which may be considered as a ‘proton escalator’.
基金supported by the National Natural Science Foundation of China(21401095,21801107,22178157)the Natural Science Foundation of Shandong Province(ZR2022MB010,ZR2019MB068,ZR2021QB123)+5 种基金the Project of Shandong Province Higher Educational Science and Technology Program(KJ2018BZC043 and J18KA113)the Liaocheng University Start-up Fund for Doctoral Scientific Research(318050104 and 318052017)the Scientific Research Fund of Liaocheng University(318011913)the Youth Innovation Team of Shandong Colleges and Universities(2019KJC027 and 2020KJC012)the Open Fund of Liaocheng University(2020CESNCTKL02)the Shandong Students Innovation and Entrepreneurship Training Program(319260210).
文摘Exploitation of stable proton conducting materials with high stability and excellent conductivity is becom-ing more important but challenging.Herein,two novel porous transition metal-organic frameworks(MOFs),formulated as[Zn(btzip)(H_(2)O)]·H_(2)O(LCUH-107)and[Ni(btzip)(H_(2)btzip)]·4H_(2)O(LCUH-108),are successfully synthesized.LCUH-107 and LCUH-108 exhibit excellent thermal and chemical stabilities.LCUH-108 has a suitable pore size(8.36Å×5.74Å)to load trifluoroacetic acid(TFA,5.72Å×5.65Å×5.06Å),which is larger than that of LCUH-107(3.50Å×2.04Å).Therefore,TFA molecules can be loaded into the pores of LCUH-108 while they were only loaded onto the surface of LCUH-107.Both TFA/LCUH-107(2.95×10^(-2)S cm^(−1))and TFA@LCUH-108(2.05×10^(-1)S cm^(−1))exhibit excellent proton con-duction at 80℃and 100%relative humidity(RH);in particular,the proton conductivity value of TFA@LCUH-108 can be as high as 10-1 S cm^(−1),which might be due to the fact that TFA molecules can be confined into their suitable pores and finally form strong continuous and stable hydrogen-bonding networks.The TFA molecules loaded into the suitable pores of LCUH-108 play a key role in improving greatly the proton conductivity of LCUH-108,while TFA molecules loaded onto the surface of LCUH-107 can only slightly improve the proton conductivity of LCUH-107,which can be confirmed by various con-trast tests and simulated calculations.This work gives a novel strategy to design efficient artificial crystal-line catalysts for proton conduction.
基金financial support from the National Natural Science Foundation of China(No.21601109).
文摘A family of isostructural heterometallic MOFs based on Fe_(2)M clusters(MOF-Fe_(2)M;M=Fe,Co and Ni,respectively)have been synthesized and serve as potential proton conductors and photocatalysts for CO_(2)photoreduction,exhibiting varied proton conductivities and photocatalytic performances.
基金financial support from the National Natural Science Foundation of China(No.21471028,21671036)National Key Basic Research Program of China(No.2013CB834802)+1 种基金Changbai Mountain Scholarship,Natural Science Foundation of Jilin Province(No.20150101064JC)the Fundamental Research Funds for the Central Universities(No.2412017BJ004).
文摘The development of new proton-conducting materials that are cost effective and have high proton conductivity and water stability is very important in fuel cell technology.Lanthanide-based metal-organic frameworks(MOFs)exhibit proton conduction properties but usually display the problem of poor hydrophilicity.We propose that the organic ligands can be replaced with polyoxometalates,and the as-prepared lanthanide-based inorganic porous materials with lanthanide ions may possess improved hydrophilicity and proton conductivity.Herein,we re-synthesize two inorganic open frameworks based on[MnV_(13)O_(38)]^(7-)clusters and lanthanide ions(H[Ln(H_(2)O)_(2)]2[MnV_(13)O_(38)]·9NMP·17H_(2)O(Ln=Ce(1),and La(2);NMP=N-methyl-2-pyrrolidone))and explore their potential proton conductivities.Under the same test conditions,both compounds show only a little difference in proton conductivities with the values of 4.68×10^(-3)S cm^(-1)and 3.46×10^(-3)S cm^(-1)at 61℃,respectively,which are much higher than those of the previously reported proton-conducting materials based on lanthanide metal ions.In addition,we also prove their proton-conducting nature by measuring the electron resistance via the Hebb-Wagner polarization technique and proton conduction via the D_(2)O-exchange test.The 3D channel in the two compounds plays a key role in constructing an efficient proton transfer pathway via a hydrogen bonding network.
基金the project approval(JRR-3 proposal no.24609,J-PARC:proposal no.2024A0178 and 2020L0804)supported by JSPS KAKENHI Grant Numbers JP21K18182,JP23K04887,JP23H04618,and JP24H00041,Adopting Sustainable Partnerships for Innovative Research Ecosystem(ASPIRE)from the Japan Science and Technology Agency(JST)(grant JPMJAP2308)+1 种基金the Adaptable and Seamless Technology Transfer Program through Target-Driven R&D(A-STEP)from JST(grant JPMJTR22TC),the Institute for Solid State Physics,the University of Tokyo,and the GIMRT Program of the Institute for Materials Research,Tohoku University(202403-CNKXX-0030,202405-CNKXX-0036,202412-QBKNE-0008,202412-QBKNE-0009)K.S.acknowledges support from a JSPS Fellowship for Young Scientists,DC1(23KJ0953).
文摘Ceramic proton conductors are promising materials for clean energy.In contrast to the conventional acceptor doping,donor doping into the oxides with intrinsic oxygen vacancies is a novel strategy to achieve the reduced proton trapping.Here,we report high proton conductivity(e.g.,0.01 S cm^(-1) at 320℃)and high chemical stability of pentavalent donor doped BaScO_(2.5),BaSc_(0.75)Nb_(0.25)O_(2.75).The high proton conductivity is attributable to high proton concentration and high proton diffusion coefficient.The high proton concentration is ascribed to a large amount of oxygen vacancies in BaSc_(0.75)Nb_(0.25)O_(2.75) and full hydration in hydrated BaSc_(0.75)Nb_(0.25)O_(2.75).The high proton diffusion coefficient is attributable to its low activation energy,suggesting reduced proton trapping due to the repulsion between the donor Nb^(5+)dopant and protons.The repulsion is clearly shown by the ab initio molecular dynamics simulations.
基金supported by the National Natural Science Foundation of China(No.21476115)the Natural Science Foundation of Jiangsu Province(No.BK20181374)+1 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_1027)the Cultivation Program for the Excellent Doctoral Dissertation of Nanjing Tech University(2020-03)for financial support.
文摘Porous crystalline metal–organic frameworks (MOFs) bearing sulfonic groups (–SO_(3)H) are receiving increasing attention as solid-state proton conductors because the –SO_(3)H group can not only enhance the proton concentration, but also form hydrogen bonding networks for high proton conductivity. A large number of 1,4-phenyldicarboxylic acids or biphenyldicarboxylic acids bearing two –SO_(3)H groups have been applied for the synthesis of proton-conducting MOFs. Surprisingly, 4,4′-biphenyldicarboxylic acid bearing one –SO_(3)H group has never been explored for the construction of proton-conducting materials. Herein, we first designed and synthesized 2-sulfonyl-4,4′-biphenyldicarboxylic acid (H_(3)L). By applying this ligand to react with lanthanide salts, a series of three-dimensional MOFs, (Me_(2)NH_(2))_(2)(H_(3)O)[LnL_(2)]·8H_(2)O (Ln=Eu (1), Gd (2), Tb (3)) have been prepared. Due to the presence of the uncoordinated –SO_(3)H group and the encapsulation of high concentrations of dimethylammonium and hydronium cations in the cavity, the MOFs 1–3 show a high proton conductivity (8.83 × 10^(-3) S cm^(-1)) at 95℃ and 60% relative humidity (RH). More importantly, this high proton conductivity can be maintained over 72 hours without any significant decrease at low RH.
