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
Desilication kinetics of calcined boron mud(CBM) occurring in molten sodium hydroxide media was investigated. The effects of factors such as reaction temperature and Na OH-to-CBM mass ratio on silicon extraction effic...Desilication kinetics of calcined boron mud(CBM) occurring in molten sodium hydroxide media was investigated. The effects of factors such as reaction temperature and Na OH-to-CBM mass ratio on silicon extraction efficiency were studied. The results show that silicon extraction efficiency increases with increasing the reaction time and Na OH-to-CBM mass ratio. There are two stages for the desilication process of the calcined boron mud. The overall desilication process follows the shrinking-core model, and the first and second stages of the process were determined to obey the shrinking-core model for surface chemical reaction and the diffusion through the product layer, respectively. The activation energies of the first and second stages were calculated to be 44.78 k J/mol and 15.94 k J/mol, respectively.展开更多
The feasibility of using liquid nitrogen cold trap （LNCT） for the removal of water vapour and alkaline mist from the hydrogen gas stream which is generated from the catalytic and acidic decomposition of sodium boroh...The feasibility of using liquid nitrogen cold trap （LNCT） for the removal of water vapour and alkaline mist from the hydrogen gas stream which is generated from the catalytic and acidic decomposition of sodium borohydride is investigated. Practically, the target application is mobile fuel cells based on hydrogen production from storage in chemical hydrides. The LNCT would be used as a one step purification method with less cost and space requirements instead of applying the conventional purification techniques. Two catalysts were investigated for the production of hydrogen from the aqueous solution of NaBH4 in a small scale packed bed reaction column. The hydrogen generated from the catalytic decomposition of NaBH4 was accompanied by limited quantity of water vapour and alkaline mist. Nonetheless, higher quantities were generated when applying the acidic decomposition of NaBH4 and consequently the utilization of LNCT for H2 purification has proved useful and lead to a reduction in the content of these impurities; thereby the concentration of hydrogen in the outlet stream has increased.展开更多
Tremendous efforts have been devoted to the synthesis of new light element hydrides for hydrogen storage. Ammonia borane （AB） is a promising candidate possessing high hydrogen capacity and low dehydrogenation temper...Tremendous efforts have been devoted to the synthesis of new light element hydrides for hydrogen storage. Ammonia borane （AB） is a promising candidate possessing high hydrogen capacity and low dehydrogenation temperature. The step-wise dehydrogenation and release of by-products, however, are obstacles to its practical application. Chemical modifications of AB to synthesize new compounds or its derivatives are of practical and fundamental importance. Here we report an improved synthesis of sodium aminodiborane （NaNH2（BH3）2, NaABB）, a derivative of ammonia borane. This procedure leads to high purity NaABB by reacting NaNH2 and 2 eq. AB. The dehydrogenation properties have been investigated by means of temperature programmed desorption-mass spectrometry, volumetric release, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and X-ray diffraction. In a closed vessel, NaABB can release -2 eq. H2 when heated at 271 ℃, forming solid products of NaBH4 and highly condensed polyborazylene.展开更多
Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced(η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru–H···HO dihydrogen bonded complex(...Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced(η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru–H···HO dihydrogen bonded complex(η5-C5H4CH2OH) RuH(PPh3)2. The dihydrogen bonded complex(η5-C5H4CH2OH)RuH(PPh3)2 could also be synthesized by the reduction of complex(η5-C5H4CHO)RuH(PPh3)2, which was obtained by the reaction of RuHCl(PPh3)3 with 6-dimethylaminopentafulvene in the presence of water. The analogous dihydrogen bonded osmium complex(η5-C5H4CH2OH)OsH(PPh3)2 was similarly prepared. Single crystal structures and DFT calculations support the presence of intra-molecular H···H interaction, with separations of around 1.9 to 2.0 .展开更多
A new hydrogen storage route of 3D nanoporous sodium borohydride (NPSB) generated by removing special atoms is proposed in this work. Three different size pores of NPSB-1 (7), NPSB-2 (10) and NPSB-3 (14) are presented...A new hydrogen storage route of 3D nanoporous sodium borohydride (NPSB) generated by removing special atoms is proposed in this work. Three different size pores of NPSB-1 (7), NPSB-2 (10) and NPSB-3 (14) are presented, and the hydrogen storage capacities of these NPSBs are simulated by employing a grand canonical Monte Carlo (GCMC) procedure for a temperature range of 77-298 K and a pressure range of 0.1-100 bar. The effects of pore diameter, temperature and pressure on the hydrogen adsorption have been examined. The results show that the adsorption of hydrogen decreases and increases with increasing temperature and hydrogen pressure, respectively. It also reflects that the hydrogen adsorption capacities at higher pressures are dependent on pore diameter, while independent of pore diameter at lower pressures.展开更多
In this article, we present a facile, direct, synthetic approach of preparing monodisperse [Au2s（SePh）ls]- nanoclusters in high yield. In this synthetic approach, two-phase Brust-Schiffrin method is used. Both PhSeH...In this article, we present a facile, direct, synthetic approach of preparing monodisperse [Au2s（SePh）ls]- nanoclusters in high yield. In this synthetic approach, two-phase Brust-Schiffrin method is used. Both PhSeH and NaBH4 should be added drop-wise to the solution of Au （III） at the same time. The formula and molecular purity of [Au25（SePh）ls] TOA＋ clusters are characterized by MALDI-TOF mass spectrometry, NMR and TGA analysis. Furthermore, some critical parameters to obtain pure [Au25（SePh）18]-TOA＋ are identified, including the NaBH4-to-Au ratio, the selenolate-to-Au ratio and the temperature. The facile, direct, high yield synthetic method can be widely applied in the theoretical research of Au clusters protected by selenol.展开更多
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.
基金Project(51204037)supported by the National Natural Science Foundation of ChinaProject(N140204016)supported by the Fundamental Research Funds for the Central Universities,China
文摘Desilication kinetics of calcined boron mud(CBM) occurring in molten sodium hydroxide media was investigated. The effects of factors such as reaction temperature and Na OH-to-CBM mass ratio on silicon extraction efficiency were studied. The results show that silicon extraction efficiency increases with increasing the reaction time and Na OH-to-CBM mass ratio. There are two stages for the desilication process of the calcined boron mud. The overall desilication process follows the shrinking-core model, and the first and second stages of the process were determined to obey the shrinking-core model for surface chemical reaction and the diffusion through the product layer, respectively. The activation energies of the first and second stages were calculated to be 44.78 k J/mol and 15.94 k J/mol, respectively.
文摘The feasibility of using liquid nitrogen cold trap （LNCT） for the removal of water vapour and alkaline mist from the hydrogen gas stream which is generated from the catalytic and acidic decomposition of sodium borohydride is investigated. Practically, the target application is mobile fuel cells based on hydrogen production from storage in chemical hydrides. The LNCT would be used as a one step purification method with less cost and space requirements instead of applying the conventional purification techniques. Two catalysts were investigated for the production of hydrogen from the aqueous solution of NaBH4 in a small scale packed bed reaction column. The hydrogen generated from the catalytic decomposition of NaBH4 was accompanied by limited quantity of water vapour and alkaline mist. Nonetheless, higher quantities were generated when applying the acidic decomposition of NaBH4 and consequently the utilization of LNCT for H2 purification has proved useful and lead to a reduction in the content of these impurities; thereby the concentration of hydrogen in the outlet stream has increased.
基金financially supported by the National Natural Science Foundation of China(U1232120,21273229)the Australian Research Council Discovery Early Career Research Award(DE120101496)
文摘Tremendous efforts have been devoted to the synthesis of new light element hydrides for hydrogen storage. Ammonia borane （AB） is a promising candidate possessing high hydrogen capacity and low dehydrogenation temperature. The step-wise dehydrogenation and release of by-products, however, are obstacles to its practical application. Chemical modifications of AB to synthesize new compounds or its derivatives are of practical and fundamental importance. Here we report an improved synthesis of sodium aminodiborane （NaNH2（BH3）2, NaABB）, a derivative of ammonia borane. This procedure leads to high purity NaABB by reacting NaNH2 and 2 eq. AB. The dehydrogenation properties have been investigated by means of temperature programmed desorption-mass spectrometry, volumetric release, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and X-ray diffraction. In a closed vessel, NaABB can release -2 eq. H2 when heated at 271 ℃, forming solid products of NaBH4 and highly condensed polyborazylene.
基金supported by the Hong Kong Research Grant Council(HKUST 602611,HKUST-601812,CUHK7/CRF/12G-2)
文摘Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced(η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru–H···HO dihydrogen bonded complex(η5-C5H4CH2OH) RuH(PPh3)2. The dihydrogen bonded complex(η5-C5H4CH2OH)RuH(PPh3)2 could also be synthesized by the reduction of complex(η5-C5H4CHO)RuH(PPh3)2, which was obtained by the reaction of RuHCl(PPh3)3 with 6-dimethylaminopentafulvene in the presence of water. The analogous dihydrogen bonded osmium complex(η5-C5H4CH2OH)OsH(PPh3)2 was similarly prepared. Single crystal structures and DFT calculations support the presence of intra-molecular H···H interaction, with separations of around 1.9 to 2.0 .
基金the National Natural Science Foundation of China (Grant Nos. 11074176 and 10976019)the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20100181110080)
文摘A new hydrogen storage route of 3D nanoporous sodium borohydride (NPSB) generated by removing special atoms is proposed in this work. Three different size pores of NPSB-1 (7), NPSB-2 (10) and NPSB-3 (14) are presented, and the hydrogen storage capacities of these NPSBs are simulated by employing a grand canonical Monte Carlo (GCMC) procedure for a temperature range of 77-298 K and a pressure range of 0.1-100 bar. The effects of pore diameter, temperature and pressure on the hydrogen adsorption have been examined. The results show that the adsorption of hydrogen decreases and increases with increasing temperature and hydrogen pressure, respectively. It also reflects that the hydrogen adsorption capacities at higher pressures are dependent on pore diameter, while independent of pore diameter at lower pressures.
基金the financial support by the National Natural Science Foundation of China (20871112, 21072001, 21372006)Changjiang Scholars Program+1 种基金the Scientific Research Foundation for Returning Overseas Chinese Scholars, State Education Ministry, Ministry of Human Resources and Social Security, Anhui Province International Scientific and Technological Cooperation Project211 Project of Anhui University
文摘In this article, we present a facile, direct, synthetic approach of preparing monodisperse [Au2s（SePh）ls]- nanoclusters in high yield. In this synthetic approach, two-phase Brust-Schiffrin method is used. Both PhSeH and NaBH4 should be added drop-wise to the solution of Au （III） at the same time. The formula and molecular purity of [Au25（SePh）ls] TOA＋ clusters are characterized by MALDI-TOF mass spectrometry, NMR and TGA analysis. Furthermore, some critical parameters to obtain pure [Au25（SePh）18]-TOA＋ are identified, including the NaBH4-to-Au ratio, the selenolate-to-Au ratio and the temperature. The facile, direct, high yield synthetic method can be widely applied in the theoretical research of Au clusters protected by selenol.
