It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quan...It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quantitative yields with relatively narrow molecular weight distributions （MWDs = 1.1-1.5） which depend on the reaction temperature. End groups of the produced polypeptide are studied in detail by MALDI-ToF MS, IH-NMR, 13C-NMR, IH-1H COSY and IH-13C HMQC analyses. The results indicate that α-hydroxy-ω-aminotelechelic polypeptides are formed which are suitable for post- polymerization functionalization.展开更多
Complexes of lanthanide trisborohydrides, formally Ln（BH4）3（THF）, （Ln=La, Ce, Sm, Yb）, were synthesized and their catalytic activity for polymerization of ε-caprolactone was studied. All the complexes can catal...Complexes of lanthanide trisborohydrides, formally Ln（BH4）3（THF）, （Ln=La, Ce, Sm, Yb）, were synthesized and their catalytic activity for polymerization of ε-caprolactone was studied. All the complexes can catalyze this polymerization. It was found that the catalytic activities decreased in the order of La〉Ce〉Sm〉Yb. The crystal structure of cerium trisborohydride was determined for the first time by single crystal X-ray diffraction analysis. It is an ionic pair complex of [Ce（BH4）E（THF）5][Ce（BH4）4（THF）2]. The cationic part involves two ηa-BH4 ligands, while the anionic part involves two η3-BH4 groups and two η2-BH4 groups.展开更多
LiBH_(4) and Mg(BH_(4))_(2) with high theoretical hydrogen mass capacity receive significant attentions for hy-drogen storage.Also,these compounds can be potentially applied as solid-state electrolytes with their high...LiBH_(4) and Mg(BH_(4))_(2) with high theoretical hydrogen mass capacity receive significant attentions for hy-drogen storage.Also,these compounds can be potentially applied as solid-state electrolytes with their high ionic conductivity.However,their applications are hindered by the poor kinetics and reversibility for hydrogen storage and low ionic conductivity at room temperature,respectively.To address these challenges,effective strategies towards engineering the hydrogen storage properties and the emerging solid-state electrolytes with improved performances have been summarized.The focuses are on the state-of-the-art developments of Li/Mg-based borohydrides with a parallel comparison of similar methods ap-plied in both hydrogen storage and solid-state electrolytes,particularly on the phase,structure,and thermal properties changes of Li/Mg-based borohydrides induced by milling,ion substitution,coordination,adding additives/catalysts,and hydrides.The similarities and differences between the strategies towards two kinds of applications are also discussed and prospected.The review will shed light on the future development of Li/Mg-based borohydrides for hydrogen storage and solid-state electrolytes.展开更多
Lithium borohydride(LiBH_(4))is regarded as a potential hydrogen storage material due to its high gravi-metric and volumetric capacity,but its practical application suffers from high operating temperature and poor rev...Lithium borohydride(LiBH_(4))is regarded as a potential hydrogen storage material due to its high gravi-metric and volumetric capacity,but its practical application suffers from high operating temperature and poor reversibility.Herein,porous hollow carbon microspheres composed of carbon-coated Ni nanoparti-cles with high content(denoted as Ni/C)are rationally designed as functional support,which not only induces effective nanoconfinement of LiBH4 but also promotes efficiently homogeneous destabilization reaction between LiBH4 and Ni nanoparticles.The introduction of Ni nanoparticles leads to the decrease of the Gibbs free energy change for H_(2)desorption of LiBH4 based on the formation of Ni_(2)B down to−0.95 eV while this value reaches 1.19 eV for bulk LiBH4,validating the effective role of Ni in thermo-dynamically destabilizing H_(2)desorption.Impressively,the average B-H bond length of LiBH4 on Ni_(2)B reaches 1.291A and thus the corresponding dissociation energy of removing one H atom from LiBH4 is lowered to 1.00 eV,much lower than bulk LiBH4(4.22 eV)and even LiBH4 on Ni(1.27 eV),which verifies superior role of Ni_(2)B than Ni in catalytically enhancing H_(2)desorption.Therefore,a capacity of 8.86 wt.%is obtained for LiBH4 confined into Ni/C at 320℃ after 10 cycles.展开更多
A novel and simple synthetic way using NaBH4 in the mixure of H2O-THF was applied to prepare 1,2-bis(diphenylphosphinoborane)ethane, dppe(BH3)2, in high yield and purity. The phosphanylborohydride compound dppe(BH3)2 ...A novel and simple synthetic way using NaBH4 in the mixure of H2O-THF was applied to prepare 1,2-bis(diphenylphosphinoborane)ethane, dppe(BH3)2, in high yield and purity. The phosphanylborohydride compound dppe(BH3)2 was isolated in the form of colorless crystals and characterized by single crystal X-ray diffraction, 1H, 13C, 31P and 11B NMR spectroscopy. Prismatic colorless crystals of dppe(BH3)2 were obtained in monoclinic crystal system and space group P21 with two asymmetric units in the unit cell. Lattice parameters were: a = 11.657(2), b = 17.237(2), c = 12.764(2) ?, β = 98.735(14)°, 2535.0(7) ?展开更多
Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discu...Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discussed.It is found that after the addition of Sn promoter,the specific surface area and the generation of active CoB phase are increased,while the oxidation treatment of CNTs results in more loading amounts of active components and enrichment of electron at active sites as well as large surface area.Consequently,the Sn-doped CoB catalysts supported on CNTs with oxidation treatment exhibits a significantly improved activity with a high H_(2)generation rate of 2640 mL/(min·g).Meanwhile,this catalyst shows a low activation energy of 43.7 kJ/mol and relatively high reusability.展开更多
Herein the use of rare-earth compounds in catalytic reduction systems for the end-group functionalization of carboxyl-terminated low-molecularweight fluoropolymers was explored.Leveraging the high catalytic activity a...Herein the use of rare-earth compounds in catalytic reduction systems for the end-group functionalization of carboxyl-terminated low-molecularweight fluoropolymers was explored.Leveraging the high catalytic activity and selectivity of rare-earth compounds along with no residual impact on polymer product's performance,highly efficient catalytic reduction systems containing sodium borohydride(NaBH_(4))and rare-earth chloride(RECl_(3))were specifically designed for a telechelic carboxyl-terminated liquid fluoroeslastomer,aiming to facilitate the conversion of chainend carboxyl groups into hydroxyl groups and improvement in end-group reactivity.To achieve this,lanthanum chloride(LaCl_(3)),cerium chloride(CeCl_(3)),and neodymium chloride(NdCl_(3))were used separately to form catalytic reduction systems with NaBH_(4).The effects of solvent dosage,reaction temperature,reaction time length,and reductant dosage on carboxylic conversion were investigated,and the molecular chain structure,molecular weight,and functional group content of the raw materials and the products were analyzed and characterized by means of infrared spectroscopy(FTIR),proton nuclear magnetic resonance(^(1)H-NMR),fluorine-19 nuclear magnetic resonance(^(19)F-NMR),gel permeation chromatography(GPC),and chemical titration.Moreover,the catalytic activity and selectivity of the rare-earth chlorides,as well as the corresponding underlying interactions were discussed.Results indicated that the rare-earth-containing catalytic reduction systems studied in this work could efficiently convert the chain-end carboxyl groups into highly active hydroxyl groups,with a highest conversion up to 87.0%and differing catalytic reduction activities ranked as NaBH_(4)/CeCl_(3)>NaBH_(4)/LaCl_(3)>NaBH_(4)/NdCl_(3).Compared with the conventional lithium aluminum hydride(LiAIH_(4))reduction system,the NaBH_(4)/RECl_(3)systems provide multiple advantages such as mild reaction conditions,high conversion ratio with good selectivity,and environmental innocuity,and are potentially applicable as new reduction-catalysis combinations for the synthesis and functionalization of polymer materials.展开更多
Direct borohydride hydrogen peroxide fuel cells(DBHPFCs)are emerging as a transformative technology for sustainable energy conversion.Despite their potential,their efficiency is largely hindered by the limitations of ...Direct borohydride hydrogen peroxide fuel cells(DBHPFCs)are emerging as a transformative technology for sustainable energy conversion.Despite their potential,their efficiency is largely hindered by the limitations of the anode catalyst.In response to this challenge,we have developed a novel series of Co-based heterojunction metal-organic framework(MOF)derivatives,supported on reduced graphene oxide(rGO)-modified nickel foam(NF),to enhance borohydride electrooxidation performance.Our synthesis involves the thermal transformation of a ZIF67-Co(OH)_(2)-rGO/NF precursor within a controlled temperature between 300 and 750℃,yielding distinct phase heterostructures and pristine Co and CoO,verified by X-ray diffraction(XRD)and transmission electron microscopy(TEM)analyses.Additionally,the Ultraviolet photoelectron spectroscopy and theoretical calculation result further validate the formation of the heterojunction and direction of electron transfer along the interface as well as the BH_(4)^(-)adsorption behavior across the heterointerface.Notably,the catalyst annealed at 600℃,designated Co-CoO@C-rGO/NF-600,exhibits an exceptional oxidation current density of 2.5 A cm^(-2)at 0 V vs.Ag/AgCl in an electrolyte containing 2 mol L^(-1)NaOH and 0.4 mol L^(-1)NaBH_(4)Furthermore,the Co-CoO@C-rGO/NF-600 catalyst demonstrates remarkable performance as the anode catalyst in a DBHPFC assembly,achieving a peak power density of 385.73 mW cm^(-2)and demonstrating the enduring operational stability.The superior electrocatalytic performance is primarily attributed to the synergistic effects of Co-CoO nanoparticles rich in active heterointerfaces and the superior electron mobility afforded by the rGO scaffold.These results not only deepen our understanding of anode catalyst design for DBHPFCs but also pave the way for breakthroughs in electrocatalytic technologies,driving forward the quest for sustainable energy solutions.展开更多
High-entropy materials have become high-activity electrocatalysis owing to their high-entropy effect and multiple active sites.Herein,we synthesize a series of carbon-supported nano high-entropy oxides(HEOs/C),specifi...High-entropy materials have become high-activity electrocatalysis owing to their high-entropy effect and multiple active sites.Herein,we synthesize a series of carbon-supported nano high-entropy oxides(HEOs/C),specifically (PtFeCoNiCu)O/C,using a carbothermal shock (CTS) method for application as a cathode catalyst in direct borohydride fuel cells (DBFCs).The microstructure of the prepared catalysts was characterized by X-ray photoelectron spectroscopy,X-ray absorption fine structure,and transmission electron microscopy.The prepared (PtFeCoNiCu)O/C,with particle sizes ranging from 2 to 4 nm,demonstrates 3.94 transferred electrons towards the oxygen reduction reaction in an alkaline environment,resulting in a minimal H_(2)O_(2)yield of 2.6%.Additionally,it exhibits a Tafel slope of 61 mV dec-1,surpassing that of commercial Pt/C (82 mV dec-1).Furthermore,after 40,000 cycles of cyclic voltammetry(CV) testing,the half-wave potential of (PtFeCoNiCu)O/C shows a positive shift of 3 mV,with no notable decline in the limiting current density.When (PtFeCoNiCu)O/C is used as a cathode catalyst in DBFCs,the DBFC achieves a maximum power density of 441 mW cm^(-2)at 60°C and sustains a cell voltage of approximately 0.73 V after 52 h at 30°C.These findings confirm that HEO/C is a promising cathode catalyst for DBFCs.展开更多
A commentary on an anode-free cell design with electrochemically stable sodium borohydride solid electrolyte and pelletized aluminium current collector for sodium all-solid-state batteries is presented.First,the viabl...A commentary on an anode-free cell design with electrochemically stable sodium borohydride solid electrolyte and pelletized aluminium current collector for sodium all-solid-state batteries is presented.First,the viable strategies for implementing anode-free configuration utilizing solid-state electrolytes are briefly reviewed.Then,the remarkable work of Meng et al.on designing an anode-free sodium all-solid-state battery is elucidated.Finally,the significance of Meng’s work is discussed.展开更多
As an environmentally friendly and high-density energy carrier,hydrogen has been recognized as one of the ideal alternatives for fossil fuels.One of the major challenges faced by“hydrogen economy”is the development ...As an environmentally friendly and high-density energy carrier,hydrogen has been recognized as one of the ideal alternatives for fossil fuels.One of the major challenges faced by“hydrogen economy”is the development of efficient,low-cost,safe and selective hydrogen generation from chemical storage materials.In this review,we summarize the recent advances in hydrogen production via hydrolysis and alcoholysis of light-metal-based materials,such as borohydrides,Mg-based and Al-based materials,and the highly efficient regeneration of borohydrides.Unfortunately,most of these hydrolysable materials are still plagued by sluggish kinetics and low hydrogen yield.While a number of strategies including catalysis,alloying,solution modification,and ball milling have been developed to overcome these drawbacks,the high costs required for the“one-pass”utilization of hydrolysis/alcoholysis systems have ultimately made these techniques almost impossible for practical large-scale applications.Therefore,it is imperative to develop low-cost material systems based on abundant resources and effective recycling technologies of spent fuels for efficient transport,production and storage of hydrogen in a fuel cell-based hydrogen economy.展开更多
Rechargeable Mg batteries have attracted much attention in the past decade due to their high theoretical energy density and low production cost,in which the electrolyte is the key component that determines the overall...Rechargeable Mg batteries have attracted much attention in the past decade due to their high theoretical energy density and low production cost,in which the electrolyte is the key component that determines the overall performance.Applying solid Mg-ion electrolytes brings many benefits to rechargeable Mg bat-teries,which can improve safety under aggressive conditions and open opportunities for new electrode applications.After extensive investigations,researchers make major breakthroughs in the solid Mg-ion electrolyte field,especially in terms of Mg-ion conductivities.However,the development of solid-state Mg batteries is still at the early stage since their stable cycling has not been achieved yet.In this review,we introduce the Mg-ion conducting properties of current solid Mg-ion electrolytes,and then summarize the performances of corresponding solid-state Mg batteries.In addition,we provide a discussion on the application potentials and future directions of each type of solid Mg-ion electrolytes that are applied in solid-state Mg batteries.展开更多
In this work,the hydrogen sorption properties of the LiBH4-Mg2NiH4 composite system with the molar ratio 2:2.5 were thoroughly investigated as a function of the applied temperature and hydrogen pressure.To the best of...In this work,the hydrogen sorption properties of the LiBH4-Mg2NiH4 composite system with the molar ratio 2:2.5 were thoroughly investigated as a function of the applied temperature and hydrogen pressure.To the best of our knowledge,it has been possible to prove experimentally the mutual destabilization between LiBH4 and Mg2NiH4.A detailed account of the kinetic and thermodynamic features of the dehydrogenation process is reported here.展开更多
MgH_(2),owing to a high theoretical capacity of 2038 mAh g^(−1),is regarded as a promising anode material for lithium-ion batteries(LIBs).However,the application of MgH_(2) is still far from satisfactory due to its po...MgH_(2),owing to a high theoretical capacity of 2038 mAh g^(−1),is regarded as a promising anode material for lithium-ion batteries(LIBs).However,the application of MgH_(2) is still far from satisfactory due to its poor cycling stability.Herein,nano-crystallization of MgH_(2) as an anode is applied for all-solid-state lithium-ion batteries(ASSLIBs)using LiBH4 as a solid-state electrolyte.The self-assembly designed MgH_(2) electrode on graphene could effectively alleviate the volume expansion,prevent the agglomeration of active substances,improve the electron transfer,and enhance the electrochemical performance of the anode material.As a result,a reversible capacity of 1214 mAh g^(−1) after 50 cycles is obtained.Significantly enhanced cycle life with a notable capacity of 597 mAh g^(−1) at a current density of 400 mA g^(−1) is delivered after 200 cycles.Further investigation on full cells also exhibits great application potential on ASSLIBs.展开更多
In order to enhance the hydrogen storage properties of LiBH4,activated charcoal (AC) was used as the scaffold to confine LiBH4 in this paper.Ball milling was used to prepare LiBH4/AC composites.Experimental results sh...In order to enhance the hydrogen storage properties of LiBH4,activated charcoal (AC) was used as the scaffold to confine LiBH4 in this paper.Ball milling was used to prepare LiBH4/AC composites.Experimental results show that dehydrogenation properties of ball-milled LiBH4/AC (LiBH4/AC-BM) are greatly improved compared with that of pristine LiBH4,ball-milled LiBH4 (LiBH4-BM) and hand-milled LiBH4/AC (LiBH4/AC-HM).The onset dehydrogenation temperature of LiBH4 for LiBH4/AC-BM is around 160 ℃,which is 170 ℃ lower than that of pristine LiBH4.At around 400 ℃,LiBH4/AC-BM finishes the dehydrogenation with a hydrogen capacity of 13.6 wt%,which is approximately the theoretical dehydrogenation capacity of pure LiBH4 (13.8 wt%),while the dehydrogenation processes for LiBH4-BM and LiBH4/AC-BM do not finish even when they were heated to 600 ℃.The isothermal dehydriding measurements show that it takes only 15 min for LiBH4/AC-BM to reach a dehydrogenation capacity of 10.1 wt% at 350 ℃,whereas the pristine LiBH4 and the LiBH4/AC-HM release hydrogen less than 1 wt% under the same conditions.The dehydrogenation process and the effect of AC were discussed.展开更多
High dispersive copper nanoparticles were prepared by chemical reduction method using potassium borohydride as reducing agent.The effects of reactant ratio,concentration of CuSO4,reaction temperature,and dispersant on...High dispersive copper nanoparticles were prepared by chemical reduction method using potassium borohydride as reducing agent.The effects of reactant ratio,concentration of CuSO4,reaction temperature,and dispersant on the size of product and conversion rate were studied.The morphologies of copper nanoparticles were characterized by scanning electron microscopy.The results show that the optimum process conditions are as follows:the molar ratio of KBH4 to CuSO4 is 0.75(3:4),concentration of CuSO4 is 0.4 mol/L,reaction temperature is 30℃,and dispersant is n-butyl alcohol.The average particles size of copper powders with spherical shape gained is about 100 nm.展开更多
In order to improve the hydrogen storage properties of LiBH4-MgH2 composite, two different kinds of Nb-based catalysts, NbC and NbF5, were added to LiBH4-MgH2 composite by ball milling, and the effect of catalysts on ...In order to improve the hydrogen storage properties of LiBH4-MgH2 composite, two different kinds of Nb-based catalysts, NbC and NbF5, were added to LiBH4-MgH2 composite by ball milling, and the effect of catalysts on hydrogen storage properties of the modified LiBH4-MgH2 system was investigated. The experimental results show that LiBH4-MgH2 composite is a two-step dehydrogenation process, and Nb-based compounds can remarkably enhance its dehydrogenation kinetics. For the composite without addition of catalysts, the starting decomposition temperature for the first dehydrogenation step is around 320℃, and there is a long period of incubation time（around 220 min） for the occurrence of the second decomposition step even at high temperature of 450℃. It needs more than 10 h to complete the decomposition process and release around 9 wt% H2. After addition of 5 mol% NbF5, the starting decomposition temperature for the first dehydrogenation step is around 150℃, there is no incubation time for the second decomposition step, and it takes around 40 min to complete the second step and reaches a total dehydrogenation capacity of 9.5 wt%. NbF5 has better catalytic effect than NbC. Based on the hydrogenation/dehydrogenation behaviors and structural variation, the mechanism of catalytic effect was discussed.展开更多
Stability of borohydrides is determined by the localization of the negative charge on the boron atom.Ionic liquids(ILs) allow to modify the stability of the borohydrides and promote new dehydrogenation pathways with a...Stability of borohydrides is determined by the localization of the negative charge on the boron atom.Ionic liquids(ILs) allow to modify the stability of the borohydrides and promote new dehydrogenation pathways with a lower activation energy. The combination of borohydride and IL is very easy to realize and no expensive rare earth metals are required. The composite of the ILs with complex hydrides decreases the enthalpy and activation energy for the hydrogen desorption. The Coulomb interaction between borohydride and IL leads to a destabilization of the materials with a significantly lower enthalpy for hydrogen desorption. Here, we report a simple ion exchange reaction using various ILs, such as vinylbenzyltrimethylammonium chloride([VBTMA][Cl]), 1-butyl-3-methylimidazolium chloride([bmim][Cl]), and 1-ethyl-1-methylpyrrolidinium bromide([EMPY][Br]) with NaBH4 to decrease the hydrogen desorption temperature. Dehydrogenation of 1-butyl-3-methylimidazolium borohydride([bmim][BH4]) starts below 100℃. The quantity of desorbed hydrogen ranges between 2.4 wt% and 2.9 wt%, which is close to the theoretical content of hydrogen. The improvement in dehydrogenation is due to the strong amine cation that destabilizes borohydride by charge transfer.展开更多
Co/Al2O3 catalyst is prepared with an impregnation-chemical reduction method and used to catalyze the methanolysis of sodium borohydride （NaBH 4） for hydrogen generation.At solution temperature of 0 C,the methanolys...Co/Al2O3 catalyst is prepared with an impregnation-chemical reduction method and used to catalyze the methanolysis of sodium borohydride （NaBH 4） for hydrogen generation.At solution temperature of 0 C,the methanolysis reaction can be effectively accelerated using Co/Al2O3 catalyst and provide a desirable hydrogen generation rate,which makes it suitable for applications under the circumstance of low environmental temperature.The byproduct of methanolysis reaction is analyzed by X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FTIR）.The characterization results indicate that methanol can be easily recovered after methanolysis reaction by hydrolysis of the methanolysis byproduct,NaB（OCH 3） 4.The catalytic activity of Co/Al2O3 towards NaBH 4 methanolysis can be further improved by appropriate calcination treatment.The catalytic methanolysis kinetics and catalyst reusability are also studied over the Co/Al2O3 catalyst calcined at the optimized temperature.展开更多
Lanthanide borohydrides Ln(BH_4)_3(THF)_3 (Ln=Yb, Er), prepared from LnCl_3 and NaBH_4 in THF, were characterized by elemental analysis, infrared spectrum and X-ray diffraction analysis. Yb(BH_4)_3(THF)_3 and Er(BH_4)...Lanthanide borohydrides Ln(BH_4)_3(THF)_3 (Ln=Yb, Er), prepared from LnCl_3 and NaBH_4 in THF, were characterized by elemental analysis, infrared spectrum and X-ray diffraction analysis. Yb(BH_4)_3(THF)_3 and Er(BH_4)_3(THF)_3 are isostructural. Each complex contains two η3-BH_4 ligands, an η2-BH_4 ligand and three THF molecules in a distorted octahedron centered about the lanthanide atom. The three B atoms in a complex are coplanar with the lanthanide atom, and the two η3-BH_4 ligands lie opposite to each other.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21174122)Special Funds for Major Basic Research Projects(No.G2011CB606001)Zhejiang Provincial Natural Science Foundation of China(No.Y4110115)
文摘It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quantitative yields with relatively narrow molecular weight distributions （MWDs = 1.1-1.5） which depend on the reaction temperature. End groups of the produced polypeptide are studied in detail by MALDI-ToF MS, IH-NMR, 13C-NMR, IH-1H COSY and IH-13C HMQC analyses. The results indicate that α-hydroxy-ω-aminotelechelic polypeptides are formed which are suitable for post- polymerization functionalization.
基金Project supported by Jiangsu Key Laboratory for the Environment Functional Materialsthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Innovation Program for Graduate Students of USTS(SKCX11S-058)
文摘Complexes of lanthanide trisborohydrides, formally Ln（BH4）3（THF）, （Ln=La, Ce, Sm, Yb）, were synthesized and their catalytic activity for polymerization of ε-caprolactone was studied. All the complexes can catalyze this polymerization. It was found that the catalytic activities decreased in the order of La〉Ce〉Sm〉Yb. The crystal structure of cerium trisborohydride was determined for the first time by single crystal X-ray diffraction analysis. It is an ionic pair complex of [Ce（BH4）E（THF）5][Ce（BH4）4（THF）2]. The cationic part involves two ηa-BH4 ligands, while the anionic part involves two η3-BH4 groups and two η2-BH4 groups.
基金H.S.acknowledges the Guangdong-Hong Kong-Macao Joint Laboratory (Grant No.2019B121205001),Macao Sci-ence and Technology Development Fund (FDCT) (Project No.0098/2020/A2),National Key Research and Development Program (No.2022YFE0206400),Natural Science Foundation of Guang-dong Province (No.2023A1515010765)and FDCT-MOST joint project (Grant No.0026/2022/AMJ)for funding.We also acknowl-edge the support of the National Natural Science Foundation of China (Grant No.52104309)Natural Science Foundation of Hubei Province (No.2021CFB011)+1 种基金“Macao Young Scholars Program”China (No.AM2020004)FDCT Funding Scheme for Postdoctoral Researchers (No.0026/APD/2021).
文摘LiBH_(4) and Mg(BH_(4))_(2) with high theoretical hydrogen mass capacity receive significant attentions for hy-drogen storage.Also,these compounds can be potentially applied as solid-state electrolytes with their high ionic conductivity.However,their applications are hindered by the poor kinetics and reversibility for hydrogen storage and low ionic conductivity at room temperature,respectively.To address these challenges,effective strategies towards engineering the hydrogen storage properties and the emerging solid-state electrolytes with improved performances have been summarized.The focuses are on the state-of-the-art developments of Li/Mg-based borohydrides with a parallel comparison of similar methods ap-plied in both hydrogen storage and solid-state electrolytes,particularly on the phase,structure,and thermal properties changes of Li/Mg-based borohydrides induced by milling,ion substitution,coordination,adding additives/catalysts,and hydrides.The similarities and differences between the strategies towards two kinds of applications are also discussed and prospected.The review will shed light on the future development of Li/Mg-based borohydrides for hydrogen storage and solid-state electrolytes.
基金supported by the National Key R&D Program of China(No.2021YFB3802400)the National Natural Sci-ence Foundation of China(Nos.22279020,22109026,51971065,51901045,U2130208,and 52071156)the Science and Technology Commission of Shanghai Municipality(Nos.21ZR1407500 and 23ZR1406500).
文摘Lithium borohydride(LiBH_(4))is regarded as a potential hydrogen storage material due to its high gravi-metric and volumetric capacity,but its practical application suffers from high operating temperature and poor reversibility.Herein,porous hollow carbon microspheres composed of carbon-coated Ni nanoparti-cles with high content(denoted as Ni/C)are rationally designed as functional support,which not only induces effective nanoconfinement of LiBH4 but also promotes efficiently homogeneous destabilization reaction between LiBH4 and Ni nanoparticles.The introduction of Ni nanoparticles leads to the decrease of the Gibbs free energy change for H_(2)desorption of LiBH4 based on the formation of Ni_(2)B down to−0.95 eV while this value reaches 1.19 eV for bulk LiBH4,validating the effective role of Ni in thermo-dynamically destabilizing H_(2)desorption.Impressively,the average B-H bond length of LiBH4 on Ni_(2)B reaches 1.291A and thus the corresponding dissociation energy of removing one H atom from LiBH4 is lowered to 1.00 eV,much lower than bulk LiBH4(4.22 eV)and even LiBH4 on Ni(1.27 eV),which verifies superior role of Ni_(2)B than Ni in catalytically enhancing H_(2)desorption.Therefore,a capacity of 8.86 wt.%is obtained for LiBH4 confined into Ni/C at 320℃ after 10 cycles.
基金Partial support of this work by the Turkish Academy of Sciences and the Scientific and Technological Research Council of Turkey(TUBITAK,Project No:105M357)is gratefully acknowledgedL.T.Y ildirim thanks Hacettepe University Scientific Research Unit(grant,No.04 A602004)for financial support.
文摘A novel and simple synthetic way using NaBH4 in the mixure of H2O-THF was applied to prepare 1,2-bis(diphenylphosphinoborane)ethane, dppe(BH3)2, in high yield and purity. The phosphanylborohydride compound dppe(BH3)2 was isolated in the form of colorless crystals and characterized by single crystal X-ray diffraction, 1H, 13C, 31P and 11B NMR spectroscopy. Prismatic colorless crystals of dppe(BH3)2 were obtained in monoclinic crystal system and space group P21 with two asymmetric units in the unit cell. Lattice parameters were: a = 11.657(2), b = 17.237(2), c = 12.764(2) ?, β = 98.735(14)°, 2535.0(7) ?
基金supported by National Natural Science Foundation of China(22276144).
文摘Carbon nanotubes(CNTs)supported CoB and CoBSn catalysts were synthesized for hydrogen production via NaBH4 hydrolysis.The roles of Sn-promoter and the effect of CNTs treatment on CoB catalysts were evaluated and discussed.It is found that after the addition of Sn promoter,the specific surface area and the generation of active CoB phase are increased,while the oxidation treatment of CNTs results in more loading amounts of active components and enrichment of electron at active sites as well as large surface area.Consequently,the Sn-doped CoB catalysts supported on CNTs with oxidation treatment exhibits a significantly improved activity with a high H_(2)generation rate of 2640 mL/(min·g).Meanwhile,this catalyst shows a low activation energy of 43.7 kJ/mol and relatively high reusability.
文摘Herein the use of rare-earth compounds in catalytic reduction systems for the end-group functionalization of carboxyl-terminated low-molecularweight fluoropolymers was explored.Leveraging the high catalytic activity and selectivity of rare-earth compounds along with no residual impact on polymer product's performance,highly efficient catalytic reduction systems containing sodium borohydride(NaBH_(4))and rare-earth chloride(RECl_(3))were specifically designed for a telechelic carboxyl-terminated liquid fluoroeslastomer,aiming to facilitate the conversion of chainend carboxyl groups into hydroxyl groups and improvement in end-group reactivity.To achieve this,lanthanum chloride(LaCl_(3)),cerium chloride(CeCl_(3)),and neodymium chloride(NdCl_(3))were used separately to form catalytic reduction systems with NaBH_(4).The effects of solvent dosage,reaction temperature,reaction time length,and reductant dosage on carboxylic conversion were investigated,and the molecular chain structure,molecular weight,and functional group content of the raw materials and the products were analyzed and characterized by means of infrared spectroscopy(FTIR),proton nuclear magnetic resonance(^(1)H-NMR),fluorine-19 nuclear magnetic resonance(^(19)F-NMR),gel permeation chromatography(GPC),and chemical titration.Moreover,the catalytic activity and selectivity of the rare-earth chlorides,as well as the corresponding underlying interactions were discussed.Results indicated that the rare-earth-containing catalytic reduction systems studied in this work could efficiently convert the chain-end carboxyl groups into highly active hydroxyl groups,with a highest conversion up to 87.0%and differing catalytic reduction activities ranked as NaBH_(4)/CeCl_(3)>NaBH_(4)/LaCl_(3)>NaBH_(4)/NdCl_(3).Compared with the conventional lithium aluminum hydride(LiAIH_(4))reduction system,the NaBH_(4)/RECl_(3)systems provide multiple advantages such as mild reaction conditions,high conversion ratio with good selectivity,and environmental innocuity,and are potentially applicable as new reduction-catalysis combinations for the synthesis and functionalization of polymer materials.
基金funded by the National Natural Science Foundation of China(No.52402106)the Natural Science Foundation of Heilongjiang Province Jointly Guided Project(No.LH2023B010)the Planning Project of Heilongjiang Province Education Department(No.LJYXL2022-036)。
文摘Direct borohydride hydrogen peroxide fuel cells(DBHPFCs)are emerging as a transformative technology for sustainable energy conversion.Despite their potential,their efficiency is largely hindered by the limitations of the anode catalyst.In response to this challenge,we have developed a novel series of Co-based heterojunction metal-organic framework(MOF)derivatives,supported on reduced graphene oxide(rGO)-modified nickel foam(NF),to enhance borohydride electrooxidation performance.Our synthesis involves the thermal transformation of a ZIF67-Co(OH)_(2)-rGO/NF precursor within a controlled temperature between 300 and 750℃,yielding distinct phase heterostructures and pristine Co and CoO,verified by X-ray diffraction(XRD)and transmission electron microscopy(TEM)analyses.Additionally,the Ultraviolet photoelectron spectroscopy and theoretical calculation result further validate the formation of the heterojunction and direction of electron transfer along the interface as well as the BH_(4)^(-)adsorption behavior across the heterointerface.Notably,the catalyst annealed at 600℃,designated Co-CoO@C-rGO/NF-600,exhibits an exceptional oxidation current density of 2.5 A cm^(-2)at 0 V vs.Ag/AgCl in an electrolyte containing 2 mol L^(-1)NaOH and 0.4 mol L^(-1)NaBH_(4)Furthermore,the Co-CoO@C-rGO/NF-600 catalyst demonstrates remarkable performance as the anode catalyst in a DBHPFC assembly,achieving a peak power density of 385.73 mW cm^(-2)and demonstrating the enduring operational stability.The superior electrocatalytic performance is primarily attributed to the synergistic effects of Co-CoO nanoparticles rich in active heterointerfaces and the superior electron mobility afforded by the rGO scaffold.These results not only deepen our understanding of anode catalyst design for DBHPFCs but also pave the way for breakthroughs in electrocatalytic technologies,driving forward the quest for sustainable energy solutions.
基金Zhejiang Provincial Natural Science Foundation of China (LZ22B060001,LY22E010003)“Pioneer” R&D Program of Zhejiang Province(2023C01080)National Natural Science Foundation of China (52301235)。
文摘High-entropy materials have become high-activity electrocatalysis owing to their high-entropy effect and multiple active sites.Herein,we synthesize a series of carbon-supported nano high-entropy oxides(HEOs/C),specifically (PtFeCoNiCu)O/C,using a carbothermal shock (CTS) method for application as a cathode catalyst in direct borohydride fuel cells (DBFCs).The microstructure of the prepared catalysts was characterized by X-ray photoelectron spectroscopy,X-ray absorption fine structure,and transmission electron microscopy.The prepared (PtFeCoNiCu)O/C,with particle sizes ranging from 2 to 4 nm,demonstrates 3.94 transferred electrons towards the oxygen reduction reaction in an alkaline environment,resulting in a minimal H_(2)O_(2)yield of 2.6%.Additionally,it exhibits a Tafel slope of 61 mV dec-1,surpassing that of commercial Pt/C (82 mV dec-1).Furthermore,after 40,000 cycles of cyclic voltammetry(CV) testing,the half-wave potential of (PtFeCoNiCu)O/C shows a positive shift of 3 mV,with no notable decline in the limiting current density.When (PtFeCoNiCu)O/C is used as a cathode catalyst in DBFCs,the DBFC achieves a maximum power density of 441 mW cm^(-2)at 60°C and sustains a cell voltage of approximately 0.73 V after 52 h at 30°C.These findings confirm that HEO/C is a promising cathode catalyst for DBFCs.
基金grateful for support from the National Natural Science Foundation of China(Nos.52472247,52172229,21401145)Fundamental Research Funds for the Central Universities(No.104972024KFYjc0079).
文摘A commentary on an anode-free cell design with electrochemically stable sodium borohydride solid electrolyte and pelletized aluminium current collector for sodium all-solid-state batteries is presented.First,the viable strategies for implementing anode-free configuration utilizing solid-state electrolytes are briefly reviewed.Then,the remarkable work of Meng et al.on designing an anode-free sodium all-solid-state battery is elucidated.Finally,the significance of Meng’s work is discussed.
基金This work was financially supported by the National Key R&D Program of China(2018YFB1502101)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(NSFC51621001)+2 种基金National Natural Science Foundation of China Projects(51771075)Natural Science Foundation of Guangdong Province of China(2016A030312011)Z.L.acknowledges the funding support from the Australian Research Council(ARC Discovery Projects,DP180102976 and DP210103539).
文摘As an environmentally friendly and high-density energy carrier,hydrogen has been recognized as one of the ideal alternatives for fossil fuels.One of the major challenges faced by“hydrogen economy”is the development of efficient,low-cost,safe and selective hydrogen generation from chemical storage materials.In this review,we summarize the recent advances in hydrogen production via hydrolysis and alcoholysis of light-metal-based materials,such as borohydrides,Mg-based and Al-based materials,and the highly efficient regeneration of borohydrides.Unfortunately,most of these hydrolysable materials are still plagued by sluggish kinetics and low hydrogen yield.While a number of strategies including catalysis,alloying,solution modification,and ball milling have been developed to overcome these drawbacks,the high costs required for the“one-pass”utilization of hydrolysis/alcoholysis systems have ultimately made these techniques almost impossible for practical large-scale applications.Therefore,it is imperative to develop low-cost material systems based on abundant resources and effective recycling technologies of spent fuels for efficient transport,production and storage of hydrogen in a fuel cell-based hydrogen economy.
基金The authors gratefully acknowledge the support of the National Natural Science Foundation of China(Nos.51971146,51971147,52171218,and 52271222)the Shanghai Municipal Science and Technology Commission(No.21010503100)+2 种基金the Major Program for the Scientific Research Innovation Plan of Shanghai Education Com-mission(No.2019-01-07-00-07-E00015)the Shanghai Outstand-ing Academic Leaders Plan,the Shanghai Rising-Star Program(No.20QA1407100)the General Program of Natural Science Foun-dation of Shanghai(No.20ZR1438400).
文摘Rechargeable Mg batteries have attracted much attention in the past decade due to their high theoretical energy density and low production cost,in which the electrolyte is the key component that determines the overall performance.Applying solid Mg-ion electrolytes brings many benefits to rechargeable Mg bat-teries,which can improve safety under aggressive conditions and open opportunities for new electrode applications.After extensive investigations,researchers make major breakthroughs in the solid Mg-ion electrolyte field,especially in terms of Mg-ion conductivities.However,the development of solid-state Mg batteries is still at the early stage since their stable cycling has not been achieved yet.In this review,we introduce the Mg-ion conducting properties of current solid Mg-ion electrolytes,and then summarize the performances of corresponding solid-state Mg batteries.In addition,we provide a discussion on the application potentials and future directions of each type of solid Mg-ion electrolytes that are applied in solid-state Mg batteries.
基金supported by the Danish Council for Strategic Research via HyFillFast
文摘In this work,the hydrogen sorption properties of the LiBH4-Mg2NiH4 composite system with the molar ratio 2:2.5 were thoroughly investigated as a function of the applied temperature and hydrogen pressure.To the best of our knowledge,it has been possible to prove experimentally the mutual destabilization between LiBH4 and Mg2NiH4.A detailed account of the kinetic and thermodynamic features of the dehydrogenation process is reported here.
基金financially supported by the National Natural Science Foundation of China(Nos.52171180,51802154,and 51971065)the National Science Fund for Distinguished Young Scholars(No.51625102)+3 种基金the Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-07-E00028)the Fundamental Research Funds for the Central Universities(No.NG2022005)the Scientific and Technological Innovation Special Fund for Carbon Peak and Carbon Neutrality of Jiangsu Province(No.BK20220039)the Open Fund for Graduate Innovation Base in Nanjing University of Aeronautics and Astronautics(No.xcxjh20210612).
文摘MgH_(2),owing to a high theoretical capacity of 2038 mAh g^(−1),is regarded as a promising anode material for lithium-ion batteries(LIBs).However,the application of MgH_(2) is still far from satisfactory due to its poor cycling stability.Herein,nano-crystallization of MgH_(2) as an anode is applied for all-solid-state lithium-ion batteries(ASSLIBs)using LiBH4 as a solid-state electrolyte.The self-assembly designed MgH_(2) electrode on graphene could effectively alleviate the volume expansion,prevent the agglomeration of active substances,improve the electron transfer,and enhance the electrochemical performance of the anode material.As a result,a reversible capacity of 1214 mAh g^(−1) after 50 cycles is obtained.Significantly enhanced cycle life with a notable capacity of 597 mAh g^(−1) at a current density of 400 mA g^(−1) is delivered after 200 cycles.Further investigation on full cells also exhibits great application potential on ASSLIBs.
基金financially supported by the National Natural Science Foundation of China(Nos. 51471149 and 51171168)the Public Project of Zhejiang Province (No. 2015C31029)
文摘In order to enhance the hydrogen storage properties of LiBH4,activated charcoal (AC) was used as the scaffold to confine LiBH4 in this paper.Ball milling was used to prepare LiBH4/AC composites.Experimental results show that dehydrogenation properties of ball-milled LiBH4/AC (LiBH4/AC-BM) are greatly improved compared with that of pristine LiBH4,ball-milled LiBH4 (LiBH4-BM) and hand-milled LiBH4/AC (LiBH4/AC-HM).The onset dehydrogenation temperature of LiBH4 for LiBH4/AC-BM is around 160 ℃,which is 170 ℃ lower than that of pristine LiBH4.At around 400 ℃,LiBH4/AC-BM finishes the dehydrogenation with a hydrogen capacity of 13.6 wt%,which is approximately the theoretical dehydrogenation capacity of pure LiBH4 (13.8 wt%),while the dehydrogenation processes for LiBH4-BM and LiBH4/AC-BM do not finish even when they were heated to 600 ℃.The isothermal dehydriding measurements show that it takes only 15 min for LiBH4/AC-BM to reach a dehydrogenation capacity of 10.1 wt% at 350 ℃,whereas the pristine LiBH4 and the LiBH4/AC-HM release hydrogen less than 1 wt% under the same conditions.The dehydrogenation process and the effect of AC were discussed.
基金Project(50834003)supported by the National Natural Science Foundation of ChinaProject(09JK561)supported by Educational Commission of Shaanxi Province of China
文摘High dispersive copper nanoparticles were prepared by chemical reduction method using potassium borohydride as reducing agent.The effects of reactant ratio,concentration of CuSO4,reaction temperature,and dispersant on the size of product and conversion rate were studied.The morphologies of copper nanoparticles were characterized by scanning electron microscopy.The results show that the optimum process conditions are as follows:the molar ratio of KBH4 to CuSO4 is 0.75(3:4),concentration of CuSO4 is 0.4 mol/L,reaction temperature is 30℃,and dispersant is n-butyl alcohol.The average particles size of copper powders with spherical shape gained is about 100 nm.
基金financially supported by the National Natural Science Foundation of China(Nos.51471149 and 51171168)the Public Project of Zhejiang Province(No.2015C31029)
文摘In order to improve the hydrogen storage properties of LiBH4-MgH2 composite, two different kinds of Nb-based catalysts, NbC and NbF5, were added to LiBH4-MgH2 composite by ball milling, and the effect of catalysts on hydrogen storage properties of the modified LiBH4-MgH2 system was investigated. The experimental results show that LiBH4-MgH2 composite is a two-step dehydrogenation process, and Nb-based compounds can remarkably enhance its dehydrogenation kinetics. For the composite without addition of catalysts, the starting decomposition temperature for the first dehydrogenation step is around 320℃, and there is a long period of incubation time（around 220 min） for the occurrence of the second decomposition step even at high temperature of 450℃. It needs more than 10 h to complete the decomposition process and release around 9 wt% H2. After addition of 5 mol% NbF5, the starting decomposition temperature for the first dehydrogenation step is around 150℃, there is no incubation time for the second decomposition step, and it takes around 40 min to complete the second step and reaches a total dehydrogenation capacity of 9.5 wt%. NbF5 has better catalytic effect than NbC. Based on the hydrogenation/dehydrogenation behaviors and structural variation, the mechanism of catalytic effect was discussed.
基金part of the activities of SCCER HeE, which is financially supported by Innosuisse – Swiss Innovation Agency
文摘Stability of borohydrides is determined by the localization of the negative charge on the boron atom.Ionic liquids(ILs) allow to modify the stability of the borohydrides and promote new dehydrogenation pathways with a lower activation energy. The combination of borohydride and IL is very easy to realize and no expensive rare earth metals are required. The composite of the ILs with complex hydrides decreases the enthalpy and activation energy for the hydrogen desorption. The Coulomb interaction between borohydride and IL leads to a destabilization of the materials with a significantly lower enthalpy for hydrogen desorption. Here, we report a simple ion exchange reaction using various ILs, such as vinylbenzyltrimethylammonium chloride([VBTMA][Cl]), 1-butyl-3-methylimidazolium chloride([bmim][Cl]), and 1-ethyl-1-methylpyrrolidinium bromide([EMPY][Br]) with NaBH4 to decrease the hydrogen desorption temperature. Dehydrogenation of 1-butyl-3-methylimidazolium borohydride([bmim][BH4]) starts below 100℃. The quantity of desorbed hydrogen ranges between 2.4 wt% and 2.9 wt%, which is close to the theoretical content of hydrogen. The improvement in dehydrogenation is due to the strong amine cation that destabilizes borohydride by charge transfer.
基金supported by the Key Project of Chinese Ministry of Education (No. 208076)Shandong Provincial Natural Science Foundation,China (No. ZR2010EM069)the Open Project of State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology
文摘Co/Al2O3 catalyst is prepared with an impregnation-chemical reduction method and used to catalyze the methanolysis of sodium borohydride （NaBH 4） for hydrogen generation.At solution temperature of 0 C,the methanolysis reaction can be effectively accelerated using Co/Al2O3 catalyst and provide a desirable hydrogen generation rate,which makes it suitable for applications under the circumstance of low environmental temperature.The byproduct of methanolysis reaction is analyzed by X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FTIR）.The characterization results indicate that methanol can be easily recovered after methanolysis reaction by hydrolysis of the methanolysis byproduct,NaB（OCH 3） 4.The catalytic activity of Co/Al2O3 towards NaBH 4 methanolysis can be further improved by appropriate calcination treatment.The catalytic methanolysis kinetics and catalyst reusability are also studied over the Co/Al2O3 catalyst calcined at the optimized temperature.
文摘Lanthanide borohydrides Ln(BH_4)_3(THF)_3 (Ln=Yb, Er), prepared from LnCl_3 and NaBH_4 in THF, were characterized by elemental analysis, infrared spectrum and X-ray diffraction analysis. Yb(BH_4)_3(THF)_3 and Er(BH_4)_3(THF)_3 are isostructural. Each complex contains two η3-BH_4 ligands, an η2-BH_4 ligand and three THF molecules in a distorted octahedron centered about the lanthanide atom. The three B atoms in a complex are coplanar with the lanthanide atom, and the two η3-BH_4 ligands lie opposite to each other.
