低价氧化铝真空碳热氯化反应机理研究

Mechanisms Responsible for Carbothermic-Chlorination of Aluminum Suboxide in Vacuum

为研究低价氧化铝、三氯化铝以及碳在真空下反应的机理,对该反应进行热力学计算,计算结果表明反应在1760K,60 Pa的条件下可以进行。采用基于密度泛函框架下的第一性原理平面波赝势法,计算得到Al2O与C、Al Cl3与C以及Al2O与Al Cl3和C的稳定结构。并用从头算分子动力学的方法模拟了它们在1760 K,60 Pa的条件下的反应过程,结果表明Al2O、Al Cl3分别在C(001)表面时,Al2O更容易发生解离,同时在C表面时Al Cl3会先发生离解,最后有吸附态的Al Cl分子和CO分子生成。

We theoretically addressed the mechanisms responsible for the carbothennic-chlorinafion of aluminum sub-oxide in vacuum. First, the influence of the reaction conditions, including but not limited to the reaction temperature and reaction pressure, was mathematically modeled and analytically calculated in thermodynamics to optimize the reaction conditions. Next, the first principle calculation by the plane-wave pseudo-potential scheme, based on density function theory （DFT） ,was performed to evaluate the stable molecular structures of Al2O and C,AlCl3 and C,A120 and AlCl3 with C, respectively. Finally,the reaction,at 1760 K and 60 Pa, was simulated in ab initio molecular dynamics calculation. The simulated results show that the gaseous Al2O is decomposed more easily than AlCl3 gas on C（001）,and that most AlCl, decomposed from AlCl3, are adsorbed on C（001）. We suggest that the calculated results may be of some basic and technological interest.