The chemisorption of hydrogen on porous graphites at low pressure and at elevated temperature
The chemisorption of hydrogen on porous graphites at low pressure and at elevated temperature
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低压高温下氢气在多孔石墨上的化学吸附
DOI：
10.1016/0022-3115(91)90418-7
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发表时间：
1991
影响因子：
3.1
通讯作者：
E. Hoinkis
中科院分区：
文献类型：
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作者：
E. Hoinkis
用于热核聚变实验的真空室的面向等离子体的部件用石墨包覆。气体的再循环影响等离子体的性质，在DT托卡马克运行过程中，石墨中氚的积累量必须知道。用容量法测定了氘在核级石墨基体A3-3上的吸附等温线，温度为1173 K，压力小于130 Pa。数据服从Langmuir型解离吸附等温线。饱和浓度为140 appm。用Fowler方程估算了0 K时的吸附能Ec = 2.5 eV/D2。EC = 2.5 eV/D2计算的等温线预测在T 700 K和P D2 0.1 Pa时石墨中吸附位的饱和。在T = 1173 K和P D2 = 10− 2 Pa时，吸附量小于饱和水平的1%。由Lennard-Jones势能图估算出CH的键能E B = 3.4eV/H，脱附活化能E d = 4 eV/H2.计算了与石墨相平衡时烃类的分压Cn = 3 Hm。在总压< 10− 2 Pa时，这些碳氢化合物的分压在600-1500 K的温度范围内小于10− 7 Pa。
The plasma facing components of the vacuum chamber for thermonuclear fusion experiments are clad with graphite. Recycling of gases affects the plasma properties, and the tritium quantity accumulated in the graphite during the operation of Tokamaks with DT must be known. An adsorption isotherm for deuterium on the nuclear grade graphitic Matrix A3-3 was measured by using a volumetric method at 1173 K at pressures< 130 Pa. The data obey a Langmuir type isotherm for dissociative adsorption. The saturation concentration is 140 appm. The adsorption energy at 0 K was estimated as E c= 2.5 eV/D 2 using Fowler's equation. The isotherms calculated for E c= 2.5 eV/D 2 predict saturation of the adsorption sites in graphite at T⩽ 700 K and P D2⩾ 0.1 Pa. At T⩾ 1173 K and P D2⩽ 10− 2 Pa the adsorbed quantity is less than 1% of the saturation level. A CH bond energy E b⋍ 3.4 eV/H and an activation energy of desorption E d⋍ 4 eV/H 2 was estimated from a Lennard-Jones potential energy diagram. The partial pressures of hydrocarbons C n⩽ 3 H m in equilibrium with graphite were calculated. At total pressures< 10− 2 Pa the partial pressures of these hydrocarbons are less than 10− 7 Pa in the temperature range 600–1500 K.