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 composition of AlLi/NaBH4 mixture activated by common Ni powder in water for hydrogen generation was investigated. The composition presents good hydrogen generation performance and an optimized Al-10% Li-10% N...A novel composition of AlLi/NaBH4 mixture activated by common Ni powder in water for hydrogen generation was investigated. The composition presents good hydrogen generation performance and an optimized Al-10% Li-10% Ni/NaBH4 mixture （mass ratio of 3：1） generates 1540 mL/g hydrogen with 96% efficiency at 333 K. Ni powder exhibits dual catalytic effects on the hydrolysis of AlLi/NaBH4 mixture due to the formation of Ni2B in the hydrolysis process. The Ni2B deposited on aluminum surface could act as a cathode of a micro galvanic couple. Ni2B/Al（OH）3 also has a synergistic effect on NaBH4 hydrolysis. Good hydrogen generation performance with stable pH value of hydrolysis byproduct Al（OH）3/NaBO2-2H2O was obtained with successive additions of Al-Li-Ni /NaBH4 mixture into fixed water.展开更多
以间苯二胺为原料,与酰化剂甲酸反应制得中间体N,N'-二甲酰基间苯二胺,再以NABH4-I2为还原剂合成得到产品N,N'-二甲基间苯二胺,对合成工艺进行了优化,并分析了还原机理,化合物的结构经IR,1 H NMR和MS分析确定.该法原料易得,反...以间苯二胺为原料,与酰化剂甲酸反应制得中间体N,N'-二甲酰基间苯二胺,再以NABH4-I2为还原剂合成得到产品N,N'-二甲基间苯二胺,对合成工艺进行了优化,并分析了还原机理,化合物的结构经IR,1 H NMR和MS分析确定.该法原料易得,反应条件要求低,收率高且成本更低.展开更多
分别采用乙二醇(EG)和H2O为溶剂,通过NaBH4还原法在酸性pH≤2和碱性pH≥12条件下制备了铂担载量为20%(质量分数)的Pt/C催化剂,利用TEM、CV及LSV等方法对催化剂进行了表征与测试,考察了EG在NaBH4还原法中对铂纳米颗粒的稳定作用。结果表...分别采用乙二醇(EG)和H2O为溶剂,通过NaBH4还原法在酸性pH≤2和碱性pH≥12条件下制备了铂担载量为20%(质量分数)的Pt/C催化剂,利用TEM、CV及LSV等方法对催化剂进行了表征与测试,考察了EG在NaBH4还原法中对铂纳米颗粒的稳定作用。结果表明,EG作溶剂、碱性pH≥12时,通过NaBH4还原法制备得到了平均粒径约2.5nm、粒径分布窄、在碳载体上分散均匀的Pt/C催化剂;该催化剂的电化学比表面为74.4m2/g Pt,0.8V vs NHE时通过LSV得到的单位质量铂对甲醇电催化氧化的电流密度为229.1mA/mg Pt,分别是相同条件下H2O作溶剂时制备得到的Pt/C催化剂的5.倍和5.3倍。展开更多
以对羟基苯乙酸为原料,用NaBH4/(CH3)2SO4/B(OCH3)3还原体系制备2-(4-羟基苯)乙醇,考察了原料配比、溶剂用量等单因素条件对目标产物收率的影响,确定了较佳工艺条件,并通过IR、HPLC和1 H NMR等对产物进行表征。结果表明:当n(NaBH4)∶n(B...以对羟基苯乙酸为原料,用NaBH4/(CH3)2SO4/B(OCH3)3还原体系制备2-(4-羟基苯)乙醇,考察了原料配比、溶剂用量等单因素条件对目标产物收率的影响,确定了较佳工艺条件,并通过IR、HPLC和1 H NMR等对产物进行表征。结果表明:当n(NaBH4)∶n(B(OCH3)3)∶n(对羟基苯乙酸)=1.8∶1.5∶1.0,无水四氢呋喃为溶剂,B(OCH3)3滴加时间为50min,30℃搅拌反应3.5h,收率可达96%以上,质量分数为99.5%。展开更多
The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions f...The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions for preparing well-dispersed nanoparticles were found as follows: 0.4 mol/L NaBH4 was added into solution containing 0.2 mol/L Cu2+, 1.0% gelatin dispersant in mass fraction, and 1.2 mol/L NH3?H2O at pH 12 and 313 K. In addition, a series of experiments were performed to discover the reaction process. NH3?H2O was found to be able to modulate the reaction process. At pH=10, Cu2+ was transformed to Cu(NH3)42+ as precursor after the addition of NH3?H2O, and then Cu(NH3)42+ was reduced by NaBH4 solution. At pH=12, Cu2+ was transformed to Cu(OH)2 as precursor after the addition of NH3?H2O, and Cu(OH)2 was then reduced by NaBH4 solution.展开更多
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Projects (21003112, 21003111) supported by the National Natural Science Foundation of ChinaProject (Y4090507) supported by the Zhejiang Basic Research Program, China
文摘A novel composition of AlLi/NaBH4 mixture activated by common Ni powder in water for hydrogen generation was investigated. The composition presents good hydrogen generation performance and an optimized Al-10% Li-10% Ni/NaBH4 mixture （mass ratio of 3：1） generates 1540 mL/g hydrogen with 96% efficiency at 333 K. Ni powder exhibits dual catalytic effects on the hydrolysis of AlLi/NaBH4 mixture due to the formation of Ni2B in the hydrolysis process. The Ni2B deposited on aluminum surface could act as a cathode of a micro galvanic couple. Ni2B/Al（OH）3 also has a synergistic effect on NaBH4 hydrolysis. Good hydrogen generation performance with stable pH value of hydrolysis byproduct Al（OH）3/NaBO2-2H2O was obtained with successive additions of Al-Li-Ni /NaBH4 mixture into fixed water.
文摘分别采用乙二醇(EG)和H2O为溶剂,通过NaBH4还原法在酸性pH≤2和碱性pH≥12条件下制备了铂担载量为20%(质量分数)的Pt/C催化剂,利用TEM、CV及LSV等方法对催化剂进行了表征与测试,考察了EG在NaBH4还原法中对铂纳米颗粒的稳定作用。结果表明,EG作溶剂、碱性pH≥12时,通过NaBH4还原法制备得到了平均粒径约2.5nm、粒径分布窄、在碳载体上分散均匀的Pt/C催化剂;该催化剂的电化学比表面为74.4m2/g Pt,0.8V vs NHE时通过LSV得到的单位质量铂对甲醇电催化氧化的电流密度为229.1mA/mg Pt,分别是相同条件下H2O作溶剂时制备得到的Pt/C催化剂的5.倍和5.3倍。
文摘以对羟基苯乙酸为原料,用NaBH4/(CH3)2SO4/B(OCH3)3还原体系制备2-(4-羟基苯)乙醇,考察了原料配比、溶剂用量等单因素条件对目标产物收率的影响,确定了较佳工艺条件,并通过IR、HPLC和1 H NMR等对产物进行表征。结果表明:当n(NaBH4)∶n(B(OCH3)3)∶n(对羟基苯乙酸)=1.8∶1.5∶1.0,无水四氢呋喃为溶剂,B(OCH3)3滴加时间为50min,30℃搅拌反应3.5h,收率可达96%以上,质量分数为99.5%。
文摘The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions for preparing well-dispersed nanoparticles were found as follows: 0.4 mol/L NaBH4 was added into solution containing 0.2 mol/L Cu2+, 1.0% gelatin dispersant in mass fraction, and 1.2 mol/L NH3?H2O at pH 12 and 313 K. In addition, a series of experiments were performed to discover the reaction process. NH3?H2O was found to be able to modulate the reaction process. At pH=10, Cu2+ was transformed to Cu(NH3)42+ as precursor after the addition of NH3?H2O, and then Cu(NH3)42+ was reduced by NaBH4 solution. At pH=12, Cu2+ was transformed to Cu(OH)2 as precursor after the addition of NH3?H2O, and Cu(OH)2 was then reduced by NaBH4 solution.
