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
The mixture of(2NaBH4+ MnCl2) was ball milled in a magneto-mill. No gas release was detected. The XRD patterns of the ball milled mixture exhibit only the Bragg diffraction peaks of the Na Cl-type salt which on the ba...The mixture of(2NaBH4+ MnCl2) was ball milled in a magneto-mill. No gas release was detected. The XRD patterns of the ball milled mixture exhibit only the Bragg diffraction peaks of the Na Cl-type salt which on the basis of the present X-ray diffraction results and the literature is likely to be a solid solution Na(Cl)x(BH4)(1-x), possessing a cubic Na Cl-type crystalline structure. No presence of any crystalline hydride was detected by powder X-ray diffraction which clearly shows that NaBH4in the initial mixture must have reacted with MnCl2forming a Na Cl-type by-product and another hydride that does not exhibit X-ray Bragg diffraction peaks. Mass spectrometry(MS) of gas released from the ball milled mixture during combined MS/thermogravimetric analysis(TGA)/differential scanning calorimetry(DSC) experiments, confirms mainly hydrogen(H2) with a small quantity of diborane gas, B2H6. The Fourier transform infra-red(FT-IR) spectrum of the ball milled(2NaBH4+ MnCl2) is quite similar to the FT-IR spectrum of crystalline manganese borohydride, c-Mn(BH4)2, synthesized by ball milling, which strongly suggests that the amorphous hydride mechano-chemically synthesized during ball milling could be an amorphous manganese borohydride. Remarkably, the process of solvent filtration and extraction at 42 °C, resulted in the transformation of mechano-chemically synthesized amorphous manganese borohydride to a nanostructured,crystalline, c-Mn(BH4)2hydride.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
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
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
Borohydrides present interesting options for the electrochemical power generation acting either as hydrogen source or anodic fuel for direct borohydride fuel cells(DBFC).In this work,Mg-Ni composite synthesized by mec...Borohydrides present interesting options for the electrochemical power generation acting either as hydrogen source or anodic fuel for direct borohydride fuel cells(DBFC).In this work,Mg-Ni composite synthesized by mechanically alloying method,used as the catalyst for the hydrolysis of borohydride,has been investigated.Co-doping treatment has been carried out for the purpose of improving the hydrolysis rate further.The as-prepared and Co-doped Mg-Ni composites with low cost showed high catalytic activity to the hydrolysis of borohydride for hydrogen generation.After Co-doping,the hydrogen generation rate was around 280 ml·g-1·min-1.Borohydride would be a promising hydrogen source for fuel cells.展开更多
Ionic liquids（ILs） are attracting much attention in various fields of chemical synthesis, electrochemical applications, liquid-liquid extractions, as well as biotransformations. Among those fields, the application o...Ionic liquids（ILs） are attracting much attention in various fields of chemical synthesis, electrochemical applications, liquid-liquid extractions, as well as biotransformations. Among those fields, the application of ILs as the potential green solvent for a wide variety of synthetic processes is an area of intense researches. High yield, high selectivity, and good catalytic charac-teristics have usually been achieved. After the isolation of products, ILs can usually be recovered and recycled many times by simple treating procedures, such as, filtration, extraction, and dryness.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
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
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
PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing ...PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.展开更多
The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte...The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte at 25 ℃ and in a direct methane proton exchange membrane fuel cell at 80 ℃. The electrocatalysts prepared also were characterized by X-ray diffraction( XRD) and transmission electron microscopy( TEM). The diffractograms of the Pt/C and Pt/C-ATO electrocatalysts show four peaks associated with Pt face-centered cubic( fcc) structure,and the diffractograms of Pd/C and Pd/C-ATO show four peaks associated with Pd face-centered cubic( fcc) structure. For Pt/C-ATO and Pd/C-ATO,characteristic peaks of cassiterite( SnO_2) phase are observed,which are associated with Sb-doped SnO_2( ATO) used as supports for electrocatalysts. Cyclic voltammograms( CV) of all electrocatalysts after adsorption of methane show that there is a current increase during the anodic scan. However,this effect is more pronounced for Pt/C-ATO and Pd/C-ATO. This process is related to the oxidation of the adsorbed species through the bifunctional mechanism,where ATO provides oxygenated species for the oxidation of CO or HCO intermediates adsorbed in Pt or Pd sites. From in situ ATR-FTIR( Attenuated Total Reflectance-Fourier Transform Infrared) experiments for all electrocatalysts prepared the formation of HCO or CO intermediates are observed,which indicates the production of carbon dioxide. Polarization curves at 80 ℃in a direct methane fuel cell( DMEFC) show that Pd/C and Pt/C electroacatalysts have superior performance to Pd/C-ATO and Pt/C-ATO in methane oxidation.展开更多
Metal borohydride ammoniates have become one of the most promising hydrogen storage materials due to their ultrahigh capacities.However,their application is still restricted by the high temperature of hydrogen desorpt...Metal borohydride ammoniates have become one of the most promising hydrogen storage materials due to their ultrahigh capacities.However,their application is still restricted by the high temperature of hydrogen desorption and the release of ammonia.Here,to promote the dehydrogenation evolution and suppress the ammonia release,different amounts of NbF 5 were introduced into Mg(BH4)2·2NH3.Compared to the pure Mg(BH_(4))_(2)·2NH_(3),the Mg(BH_(4))_(2)·2NH_(3)-NbF_(5) composites exhibit lower onset dehydriding temperatures(53–57℃)and higher dehydriding capacities(5.6 wt.%–8.2 wt.%)at below 200℃,with the complete suppression of ammonia.In addition,7.4 wt.%H_(2) could be released from Mg(BH_(4))_(2)·2NH_(3)–5 mol%NbF5 composite at 200℃ within 20 min and the apparent activation energy is calculated to be 60.28 kJ mol^(-1),which is much lower than that of pure Mg(BH_(4))_(2)·2NH_(3)(92.04 kJ mol^(-1)).Mg(BH_(4))_(2)·2NH_(3) should mechanochemically react with NbF5,forming dual-metal(Mg,Nb)borohydride ammoniate and spherical MgF2.The introduction of electronegative Nb cation results in-situ formation of(Mg,Nb)borohydride ammoniate towards a lower dehydrogenation temperature and a higher hydrogen release purity.The increased phase boundaries among the Mg(BH_(4))_(2)·2NH_(3),dual-metal(Mg,Nb)borohydride ammoniate,and MgF2 phases further facilitate the hydrogen diffusion during the dehydrogenation of the composites.展开更多
Since graphene-based materials have shown great potential in many fields,it is important to explore ultrafast and high-efficient methods to synthesize reduced graphene oxide(rGO) using inexpensive reducing agents unde...Since graphene-based materials have shown great potential in many fields,it is important to explore ultrafast and high-efficient methods to synthesize reduced graphene oxide(rGO) using inexpensive reducing agents under mild conditions.Here,we reported a novel method for the ultrafast chemical reduction of graphene oxide(GO) at room temperature using sodium borohydride(NaBH_(4)),sodium molybdate(Na_(2)MoO_(4)) and hydrochloric acid(HCl).The reduction was carried out within 2 min.A series of characterization results revealed that the obtained reduced graphene oxide has higher reduction degree than that synthesized by NaBH_(4) alone at high temperature.Moreover,rGO electrode based on the present reducing method exhibited a superior specific capacitance of 139.8 F/g at a current density of1 A/g,indicating that it can be used as electrode materials for supercapacitors.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
The facile construction of nanoscale NbH_(x)supported by Ti_(3)C_(2)(NbH_(x)@Ti_(3)C_(2))was achieved using facile ball milling strategy to improve the hydrogen desorption kinetics and reversibility of magnesium boroh...The facile construction of nanoscale NbH_(x)supported by Ti_(3)C_(2)(NbH_(x)@Ti_(3)C_(2))was achieved using facile ball milling strategy to improve the hydrogen desorption kinetics and reversibility of magnesium borohydride(Mg(BH_(4))_(2)).The doping of 30 wt%NbH_(x)@Ti_(3)C_(2)catalyst reduced the onset dehydrogenation temperature of Mg(BH_(4))_(2)to 71.2℃.Additionally,the Mg(BH_(4))_(2)+30NbH_(x)@Ti_(3)C_(2)composite achieved remarkable hydrogen release of over 9.2 wt%at a temperature as low as 230℃,indicating unexpected dehydrogenation kinetics.Moreover,the reversibility of NbH_(x)@Ti_(3)C_(2)doped Mg(BH_(4))_(2)was retained to more than 4.2 wt%after four cycles,which was increased by 68%compared to that of undoped Mg(BH_(4))_(2).The strong catalysis of NbH_(x)@Ti_(3)C_(2)catalyst could be attributed to the synergistic effect of NbH_(x)and Ti_(3)C_(2)in hydrogen spillover and diffusion.NbH_(x)acted as a"hydrogen pump"for effective hydrogen spillover,while Ti_(3)C_(2)created numerous diffusion channels for hydrogen dissolution and provided the active catalytic site to facilitate the re/dehydrogenation of Mg(BH_(4))_(2).展开更多
Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hy...Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hydrogen and enhance the utilization of borohydride, Ti/Zr metal powders has been added into the parent LmNi4.78Mn0.22 （where Lm is La-richened mischmetal） alloy （LNM） by ball milling and heat treatment methods. It is found that the addition of Ti/Zr metal powders lowers the electrochemical catalytic activity of the electrodes, at the same time, restrains the generation of hydrogen and enhances the utilization of the fuel. All the results show that the hydrogen generation rate or the utilization of the fuel is directly relative to the electrochemical catalytic activity or the discharge capability of the electrodes. The utilization of the fuel increases with discharge current density. It is very important to find a balance between the discharge capability and the utilization of the fuel.展开更多
A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described.A variety of ali...A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described.A variety of aliphatic and aromatic aldehydes,ketones and amines when mixed with NaBH;/silica chloride at room temperature,afforded excellent yield of the corresponding amines.展开更多
We reported an inexpensive and high-efficiency hydrogen generation method from NaBH4 hydrolysis promoted by oxalic acid.NaBH4 and H2C2O4 were premixed and hydrogen generation was initiated by adding water into the sol...We reported an inexpensive and high-efficiency hydrogen generation method from NaBH4 hydrolysis promoted by oxalic acid.NaBH4 and H2C2O4 were premixed and hydrogen generation was initiated by adding water into the solid mixture.H2C2O4 was selected as the acid promotor due to its solid state and low mass per proton.The effect of reactant ratio on the hydrogen yield and hydrogen storage density was investigated.With optimized reactant ratio,high gravimetric hydrogen storage up to 4.4wt%based on all the reactants can be achieved with excellent hydrogen generation kinetics.展开更多
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supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grant to Prof. R.A. Varin
文摘The mixture of(2NaBH4+ MnCl2) was ball milled in a magneto-mill. No gas release was detected. The XRD patterns of the ball milled mixture exhibit only the Bragg diffraction peaks of the Na Cl-type salt which on the basis of the present X-ray diffraction results and the literature is likely to be a solid solution Na(Cl)x(BH4)(1-x), possessing a cubic Na Cl-type crystalline structure. No presence of any crystalline hydride was detected by powder X-ray diffraction which clearly shows that NaBH4in the initial mixture must have reacted with MnCl2forming a Na Cl-type by-product and another hydride that does not exhibit X-ray Bragg diffraction peaks. Mass spectrometry(MS) of gas released from the ball milled mixture during combined MS/thermogravimetric analysis(TGA)/differential scanning calorimetry(DSC) experiments, confirms mainly hydrogen(H2) with a small quantity of diborane gas, B2H6. The Fourier transform infra-red(FT-IR) spectrum of the ball milled(2NaBH4+ MnCl2) is quite similar to the FT-IR spectrum of crystalline manganese borohydride, c-Mn(BH4)2, synthesized by ball milling, which strongly suggests that the amorphous hydride mechano-chemically synthesized during ball milling could be an amorphous manganese borohydride. Remarkably, the process of solvent filtration and extraction at 42 °C, resulted in the transformation of mechano-chemically synthesized amorphous manganese borohydride to a nanostructured,crystalline, c-Mn(BH4)2hydride.
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 Natural Science Foundation of Zhejiang Province （Y405496） the State Key Development Program for Basic Research of China （2007CB216409）
文摘Borohydrides present interesting options for the electrochemical power generation acting either as hydrogen source or anodic fuel for direct borohydride fuel cells(DBFC).In this work,Mg-Ni composite synthesized by mechanically alloying method,used as the catalyst for the hydrolysis of borohydride,has been investigated.Co-doping treatment has been carried out for the purpose of improving the hydrolysis rate further.The as-prepared and Co-doped Mg-Ni composites with low cost showed high catalytic activity to the hydrolysis of borohydride for hydrogen generation.After Co-doping,the hydrogen generation rate was around 280 ml·g-1·min-1.Borohydride would be a promising hydrogen source for fuel cells.
基金National Natural Science Foundation of China(No.20336010)National Basic Research Programme of China(No.2003CB716008)
文摘Ionic liquids（ILs） are attracting much attention in various fields of chemical synthesis, electrochemical applications, liquid-liquid extractions, as well as biotransformations. Among those fields, the application of ILs as the potential green solvent for a wide variety of synthetic processes is an area of intense researches. High yield, high selectivity, and good catalytic charac-teristics have usually been achieved. After the isolation of products, ILs can usually be recovered and recycled many times by simple treating procedures, such as, filtration, extraction, and dryness.
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 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.
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.
文摘PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy.
基金The project was supported by the FAPESP(2014/09087-4,2014/50279-4).
文摘The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte at 25 ℃ and in a direct methane proton exchange membrane fuel cell at 80 ℃. The electrocatalysts prepared also were characterized by X-ray diffraction( XRD) and transmission electron microscopy( TEM). The diffractograms of the Pt/C and Pt/C-ATO electrocatalysts show four peaks associated with Pt face-centered cubic( fcc) structure,and the diffractograms of Pd/C and Pd/C-ATO show four peaks associated with Pd face-centered cubic( fcc) structure. For Pt/C-ATO and Pd/C-ATO,characteristic peaks of cassiterite( SnO_2) phase are observed,which are associated with Sb-doped SnO_2( ATO) used as supports for electrocatalysts. Cyclic voltammograms( CV) of all electrocatalysts after adsorption of methane show that there is a current increase during the anodic scan. However,this effect is more pronounced for Pt/C-ATO and Pd/C-ATO. This process is related to the oxidation of the adsorbed species through the bifunctional mechanism,where ATO provides oxygenated species for the oxidation of CO or HCO intermediates adsorbed in Pt or Pd sites. From in situ ATR-FTIR( Attenuated Total Reflectance-Fourier Transform Infrared) experiments for all electrocatalysts prepared the formation of HCO or CO intermediates are observed,which indicates the production of carbon dioxide. Polarization curves at 80 ℃in a direct methane fuel cell( DMEFC) show that Pd/C and Pt/C electroacatalysts have superior performance to Pd/C-ATO and Pt/C-ATO in methane oxidation.
基金supported by the National Key Research and Development Plan(Grant No.2021YFB3802400)the National Natural Science Foundation of China(Grant Nos.52071141,52271212,52201250)+1 种基金the Equipment Pre-research Field Foundation(Grant No.6140721040101)the Interdisciplinary Innovation Program of North China Electric Power University(Grant No.XM2112355).
文摘Metal borohydride ammoniates have become one of the most promising hydrogen storage materials due to their ultrahigh capacities.However,their application is still restricted by the high temperature of hydrogen desorption and the release of ammonia.Here,to promote the dehydrogenation evolution and suppress the ammonia release,different amounts of NbF 5 were introduced into Mg(BH4)2·2NH3.Compared to the pure Mg(BH_(4))_(2)·2NH_(3),the Mg(BH_(4))_(2)·2NH_(3)-NbF_(5) composites exhibit lower onset dehydriding temperatures(53–57℃)and higher dehydriding capacities(5.6 wt.%–8.2 wt.%)at below 200℃,with the complete suppression of ammonia.In addition,7.4 wt.%H_(2) could be released from Mg(BH_(4))_(2)·2NH_(3)–5 mol%NbF5 composite at 200℃ within 20 min and the apparent activation energy is calculated to be 60.28 kJ mol^(-1),which is much lower than that of pure Mg(BH_(4))_(2)·2NH_(3)(92.04 kJ mol^(-1)).Mg(BH_(4))_(2)·2NH_(3) should mechanochemically react with NbF5,forming dual-metal(Mg,Nb)borohydride ammoniate and spherical MgF2.The introduction of electronegative Nb cation results in-situ formation of(Mg,Nb)borohydride ammoniate towards a lower dehydrogenation temperature and a higher hydrogen release purity.The increased phase boundaries among the Mg(BH_(4))_(2)·2NH_(3),dual-metal(Mg,Nb)borohydride ammoniate,and MgF2 phases further facilitate the hydrogen diffusion during the dehydrogenation of the composites.
文摘Since graphene-based materials have shown great potential in many fields,it is important to explore ultrafast and high-efficient methods to synthesize reduced graphene oxide(rGO) using inexpensive reducing agents under mild conditions.Here,we reported a novel method for the ultrafast chemical reduction of graphene oxide(GO) at room temperature using sodium borohydride(NaBH_(4)),sodium molybdate(Na_(2)MoO_(4)) and hydrochloric acid(HCl).The reduction was carried out within 2 min.A series of characterization results revealed that the obtained reduced graphene oxide has higher reduction degree than that synthesized by NaBH_(4) alone at high temperature.Moreover,rGO electrode based on the present reducing method exhibited a superior specific capacitance of 139.8 F/g at a current density of1 A/g,indicating that it can be used as electrode materials for supercapacitors.
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financially supported by the National Natural Science Foundation of China(No.52201255)the Natural Science Foundation of Jiangsu Province(No.BK20210884)the Innovation and Entrepreneurship Program of Jiangsu Province(No.JSSCBS20211007)。
文摘The facile construction of nanoscale NbH_(x)supported by Ti_(3)C_(2)(NbH_(x)@Ti_(3)C_(2))was achieved using facile ball milling strategy to improve the hydrogen desorption kinetics and reversibility of magnesium borohydride(Mg(BH_(4))_(2)).The doping of 30 wt%NbH_(x)@Ti_(3)C_(2)catalyst reduced the onset dehydrogenation temperature of Mg(BH_(4))_(2)to 71.2℃.Additionally,the Mg(BH_(4))_(2)+30NbH_(x)@Ti_(3)C_(2)composite achieved remarkable hydrogen release of over 9.2 wt%at a temperature as low as 230℃,indicating unexpected dehydrogenation kinetics.Moreover,the reversibility of NbH_(x)@Ti_(3)C_(2)doped Mg(BH_(4))_(2)was retained to more than 4.2 wt%after four cycles,which was increased by 68%compared to that of undoped Mg(BH_(4))_(2).The strong catalysis of NbH_(x)@Ti_(3)C_(2)catalyst could be attributed to the synergistic effect of NbH_(x)and Ti_(3)C_(2)in hydrogen spillover and diffusion.NbH_(x)acted as a"hydrogen pump"for effective hydrogen spillover,while Ti_(3)C_(2)created numerous diffusion channels for hydrogen dissolution and provided the active catalytic site to facilitate the re/dehydrogenation of Mg(BH_(4))_(2).
文摘Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hydrogen and enhance the utilization of borohydride, Ti/Zr metal powders has been added into the parent LmNi4.78Mn0.22 （where Lm is La-richened mischmetal） alloy （LNM） by ball milling and heat treatment methods. It is found that the addition of Ti/Zr metal powders lowers the electrochemical catalytic activity of the electrodes, at the same time, restrains the generation of hydrogen and enhances the utilization of the fuel. All the results show that the hydrogen generation rate or the utilization of the fuel is directly relative to the electrochemical catalytic activity or the discharge capability of the electrodes. The utilization of the fuel increases with discharge current density. It is very important to find a balance between the discharge capability and the utilization of the fuel.
基金support of this work from the Research Council of Mazandaran University gratefully acknowledged.
文摘A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described.A variety of aliphatic and aromatic aldehydes,ketones and amines when mixed with NaBH;/silica chloride at room temperature,afforded excellent yield of the corresponding amines.
基金Funded by the Ministry of Science and Technology(MOST)of China(No.2018YFB1502104)the National Natural Science Foundation of China(No.21771006)the Equipment Development Department of People’s Republic of China Central Military Commission(Pre-research Project of the Thirteenth FiveYear Plan)(No.41421020103)。
文摘We reported an inexpensive and high-efficiency hydrogen generation method from NaBH4 hydrolysis promoted by oxalic acid.NaBH4 and H2C2O4 were premixed and hydrogen generation was initiated by adding water into the solid mixture.H2C2O4 was selected as the acid promotor due to its solid state and low mass per proton.The effect of reactant ratio on the hydrogen yield and hydrogen storage density was investigated.With optimized reactant ratio,high gravimetric hydrogen storage up to 4.4wt%based on all the reactants can be achieved with excellent hydrogen generation kinetics.
