采用密度泛函理论(DFT)的B3LYP方法对Ti_2^+活化环己烷的同面脱氢机理进行理论计算,分别得到反应中涉及到的驻点、优化构型及相关的构型参数,并简单绘制了反应势能图,从而对反应机理进行详细的分析。对环己烷与Ti_2^+反应的同面脱氢机...采用密度泛函理论(DFT)的B3LYP方法对Ti_2^+活化环己烷的同面脱氢机理进行理论计算,分别得到反应中涉及到的驻点、优化构型及相关的构型参数,并简单绘制了反应势能图,从而对反应机理进行详细的分析。对环己烷与Ti_2^+反应的同面脱氢机理进行研究,研究结果表明环己烷与Ti_2^+的同面脱氢过程中三次脱氢机理相似,反应发生在混合势能面上,最终产物是二、四重态的混合物,且放热分别为54.85、28.74 k J/mol。展开更多
Titanium is one of the best hydrogen loading material. The pre dieted maximum loading ratio of hydrogen in titanium may reach to 2.0. In this work, a titanium layer on molybdenum substrate was deuterated with the atom...Titanium is one of the best hydrogen loading material. The pre dieted maximum loading ratio of hydrogen in titanium may reach to 2.0. In this work, a titanium layer on molybdenum substrate was deuterated with the atomic: ratio X =2H/Ti≥1.6. The change of the surface topography and rnicrostructurc of the sample before and after loading was observed by using Scan Electron Microscopy (SEM). The surface segregation of the samples after deutcron bombardment was also observed. A fluctuatingly-incrcasing trend of the deutcriuin density in titanium target was detected in the deuteron implantation experiments. which indicated a suddenly explosion (segregation) or fast diffusion of deuterium in the titanium. Significant amount of nitrogen contamination was found in thc Ti2Hx sample by nuclear reaction analysis (NRA), which indicated that the Ti2Hx structure might have the feature to trap nitrogen from air. The nitrogen contamination in Ti2Hx significantly affects the increase of the atomic ratio X展开更多
Amorphous Ti2?xMgxNi (x=0?0.3) alloys were prepared by mechanical milling of elemental powders. Charge and discharge test, linear polarization (LP) and potential-step measurement were carried out to investigate the el...Amorphous Ti2?xMgxNi (x=0?0.3) alloys were prepared by mechanical milling of elemental powders. Charge and discharge test, linear polarization (LP) and potential-step measurement were carried out to investigate the electrochemical hydrogen storage properties of the alloys before and after heat treatment. The results show that the maximum discharge capacity of heat-treated Ti2?xMgxNi alloy can reach 275.3 mA·h/g, which is 100 mA·h/g higher than that of the amorphous Ti2?xMgxNi alloy. The heat-treated Ti1.9Mg0.1Ni alloy presents the best cycling stability with a high discharge capacity of 210 mA·h/g after 30 cycles. The results of LP and potential-step measurement of the Ti1.9Mg0.1Ni alloy show that the exchange current density increases from 101.1 to 203.3 mA/g and the hydrogen diffusion coefficient increases from 3.20×10?11 to 2.70×10?10 cm2/s after the heat treatment, indicating that the heat treatment facilitates both the charge-transfer and hydrogen diffusion processes, resulting in an improvement in electrochemical hydrogen storage properties of Ti2?xMgxNi (x=0?0.3) alloys.展开更多
文摘采用密度泛函理论(DFT)的B3LYP方法对Ti_2^+活化环己烷的同面脱氢机理进行理论计算,分别得到反应中涉及到的驻点、优化构型及相关的构型参数,并简单绘制了反应势能图,从而对反应机理进行详细的分析。对环己烷与Ti_2^+反应的同面脱氢机理进行研究,研究结果表明环己烷与Ti_2^+的同面脱氢过程中三次脱氢机理相似,反应发生在混合势能面上,最终产物是二、四重态的混合物,且放热分别为54.85、28.74 k J/mol。
基金Supported by a fund of the Chinese Academy of Sciences the special fund of the Nuclear Power Institute of China
文摘Titanium is one of the best hydrogen loading material. The pre dieted maximum loading ratio of hydrogen in titanium may reach to 2.0. In this work, a titanium layer on molybdenum substrate was deuterated with the atomic: ratio X =2H/Ti≥1.6. The change of the surface topography and rnicrostructurc of the sample before and after loading was observed by using Scan Electron Microscopy (SEM). The surface segregation of the samples after deutcron bombardment was also observed. A fluctuatingly-incrcasing trend of the deutcriuin density in titanium target was detected in the deuteron implantation experiments. which indicated a suddenly explosion (segregation) or fast diffusion of deuterium in the titanium. Significant amount of nitrogen contamination was found in thc Ti2Hx sample by nuclear reaction analysis (NRA), which indicated that the Ti2Hx structure might have the feature to trap nitrogen from air. The nitrogen contamination in Ti2Hx significantly affects the increase of the atomic ratio X
基金Project(51201089)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions of China
文摘Amorphous Ti2?xMgxNi (x=0?0.3) alloys were prepared by mechanical milling of elemental powders. Charge and discharge test, linear polarization (LP) and potential-step measurement were carried out to investigate the electrochemical hydrogen storage properties of the alloys before and after heat treatment. The results show that the maximum discharge capacity of heat-treated Ti2?xMgxNi alloy can reach 275.3 mA·h/g, which is 100 mA·h/g higher than that of the amorphous Ti2?xMgxNi alloy. The heat-treated Ti1.9Mg0.1Ni alloy presents the best cycling stability with a high discharge capacity of 210 mA·h/g after 30 cycles. The results of LP and potential-step measurement of the Ti1.9Mg0.1Ni alloy show that the exchange current density increases from 101.1 to 203.3 mA/g and the hydrogen diffusion coefficient increases from 3.20×10?11 to 2.70×10?10 cm2/s after the heat treatment, indicating that the heat treatment facilitates both the charge-transfer and hydrogen diffusion processes, resulting in an improvement in electrochemical hydrogen storage properties of Ti2?xMgxNi (x=0?0.3) alloys.
