气相原子氢与pt111表面的相互作用体相氢物种的直接证据

在超高真空条件下利用高温钨丝裂解氢分子制备气相氢原子,并研究了气相氢原子与Pt(111)表面的相互作用.热脱附谱(TDS)结果表明气相分子氢在Pt(111)表面吸附生成表面吸附氢物种;而气相原子氢在Pt(111)表面吸附不仅生成表面吸附氢物种,而且能够生成体相氢物种.Pt(111)表面体相氢物种的热稳定性低于表面氢物种,表明体相氢物种具有更高的能量.这种弱吸附体相氢物种有可能是Pt表面催化加氢反应的活性氢物种

气相原子氢与pt111表面的相互作用体相氢物种的直接证据

在超高真空条件下利用高温钨丝裂解氢分子制备气相氢原子,并研究了气相氢原子与Pt(111)表面的相互作用.热脱附谱(TDS)结果表明气相分子氢在Pt(111)表面吸附生成表面吸附氢物种;而气相原子氢在Pt(111)表面吸附不仅生成表面吸附氢物种,而且能够生成体相氢物种.Pt(111)表面体相氢物种的热稳定性低于表面氢物种,表明体相氢物种具有更高的能量.这种弱吸附体相氢物种有可能是Pt表面催化加氢反应的活性氢物种

Effects of Methanol Contaminant in Electrolyte on Performance of Graphite Electrodes for Li-ion Batteries Studied via Electrochemical Impedance Spectroscopy

运用电化学阻抗谱和循环伏安法研究了在1 mol/L L iPF6-EC/DEC/DMC电解液中,不同甲醇杂质含量对石墨电极性能的影响及其机制.结果表明,甲醇对石墨电极性能的影响与电解液中甲醇的含量有关;其对石墨电极性能的影响机制为甲醇在2.0 V左右还原生成的甲氧基锂沉积在石墨电极表面上,形成一层初始SEI膜,影响了EC的还原分解成膜过程.Electrochemical performance of graphite electrode cycled vs.Li in 1 mol/L LiPF_(6)-EC/DEC/DMC(1∶1∶1, volume ratio) electrolyte solution,which contains different concentrations of methanol,was investigated by cyclic voltammetry and electrochemical impedance spectroscopy(EIS) in the process of first lithiation.It was demonstrated that methanol contaminant caused the deterioration of the electrochemical performance of graphite electrodes,which depends markedly on the concentration of methanol.Based on the experimental results and analysis,a mechanism of the deterioration of the electrochemical performance of graphite electrode caused by methanol contaminant was proposed.The methanol was reduced to lithium methoxide,that deposited on graphite electrode surface to form initial SEI(solid electrolyte interphase) near 2.0 V,which resulted in ethylene carbonate excess decomposition and poor passive ability of the SEI ultimately formed.国家“九七三”计划项目(批准号:2002CB211804)资

储热材料检测装备技术的研究与应用

可再生能源与工业余热具有间歇性和分散性等特点,其有效利用需要匹配高效储能装置进行资源稳定转化。储热以其高容量和经济性获得关注。本研究针对中高温复合相变储热材料,研制系列专用分析仪器装备:主要包括冷热循环寿命的测试、高温接触角的测定,和导热系数的测定等。研制样机已成功应用于实验研究,为储/释热实效分析和储能工程经济性精确分析等提供了重要数据基础

effectofprecoveredoxygenontheadsorptionanddecompositionofnoonpt110surface

The adsorption and decomposition of NO on clean and oxygen-precovered Pt(110) surfaces were investigated by means of thermal desorption spectroscopy, X-ray photoelectron spectroscopy, and high-resolution electron energy loss spectroscopy. At room temperature, NO molecularly adsorbs on the clean Pt(110) surface. NO adsorbing on the bridge sites dominates at low coverage whereas NO adsorbs on the terminal sites at high coverage. Some NO (mainly the bridge-bound NO) undergoes dissociation upon heating, forming N and N2O. Molecular oxygen dissociates on Pt(110) at room temperature. Precovered oxygen adatoms on Pt(110) inhibit the formation of bridge-bound NO, which results in a decrease in the desorption temperature of bridge-bound NO from the surface by 40 K. The decrease in the desorption temperature facilitates the thermal desorption of bridge-bound NO on Pt(110), and thus inhibits the dissociation reaction of NO. These results provide a reasonable surface science approach to understand the deactivation of Pt catalysts for NO decomposition under the oxygen rich atmosphere

effectofprecoveredoxygenontheadsorptionanddecompositionofnoonpt110surface

The adsorption and decomposition of NO on clean and oxygen-precovered Pt(110) surfaces were investigated by means of thermal desorption spectroscopy, X-ray photoelectron spectroscopy, and high-resolution electron energy loss spectroscopy. At room temperature, NO molecularly adsorbs on the clean Pt(110) surface. NO adsorbing on the bridge sites dominates at low coverage whereas NO adsorbs on the terminal sites at high coverage. Some NO (mainly the bridge-bound NO) undergoes dissociation upon heating, forming N and N2O. Molecular oxygen dissociates on Pt(110) at room temperature. Precovered oxygen adatoms on Pt(110) inhibit the formation of bridge-bound NO, which results in a decrease in the desorption temperature of bridge-bound NO from the surface by 40 K. The decrease in the desorption temperature facilitates the thermal desorption of bridge-bound NO on Pt(110), and thus inhibits the dissociation reaction of NO. These results provide a reasonable surface science approach to understand the deactivation of Pt catalysts for NO decomposition under the oxygen rich atmosphere

Effects of methanol contaminant in electrolyte on performance of graphite electrodes for Li-ion batteries studied via electrochemical impedance spectroscopy

Electrochemical performance of graphite electrode cycled vs. Li in 1 mol/L LiPF6-EC/DEC/DMC (1: 1: 1, volume ratio) electrolyte solution, which contains different concentrations of methanol, was investigated by cyclic voltammetry and electrochemical impedance spectroscopy( EIS) in the process of first lithiation. It was demonstrated that methanol contaminant caused the deterioration of the electrochemical performance of graphite electrodes, which depends markedly on the concentration of methanol. Based on the experimental results and analysis, a mechanism of the deterioration of the electrochemical performance of graphite electrode caused by methanol contaminant was proposed. The methanol was reduced to lithium methoxide, that deposited on graphite electrode surface to form initial SEI ( solid electrolyte interphase) near 2.0 V, which resulted in ethylene carbonate excess decomposition and poor passive ability of the SEI ultimately formed