含空位缺陷黄铁矿(100)表面吸附氢氧根和羟基钙的量子化学研究

Quantum chemical study of adsorption of hydroxyl and hydroxyl calcium on pyrite (100) surface bearing vacancy defects

采用密度泛函理论方法研究硫空位和铁空位缺陷对氢氧根和羟基钙在黄铁矿表面吸附的影响。计算结果表明,铁空位能减弱氢氧根的吸附,硫空位能促进氢氧根的吸附,而铁空位和硫空位缺陷都能增强羟基钙在黄铁矿表面的吸附。氢氧根在硫空位缺陷形成的活性铁原子上的吸附能力比在铁空位缺陷形成的活性硫原子上的吸附能力强。对于羟基钙分子,在硫空位缺陷存在的情况下氧原子与黄铁矿表面铁原子成键,在铁空位缺陷存在的情况下钙原子与周围的硫原子发生作用,从而促进了钙原子在黄铁矿表面空位缺陷处的吸附。

The effects of S-vacancy and Fe-vacancy on the adsorption of hydroxyl and hydroxyl calcium on the pyrite surface were investigated, respectively, by density functional theory （DFT）. The calculation results indicate that Fe-vacancy can weaken the adsorption of hydroxyl, and S-vacancy can enhance the adsorption of hydroxyl calcium. Both Fe-vacancy and S-vacancy can enhance the adsorption of hydroxyl calcium on the pyrite surface. The adsorption of hydroxyl on the iron site resulted from S-vacancy is stronger than that of the sulphur site resulted from Fe-vacancy. For the hydroxyl calcium molecule, the oxygen atom bonds with the iron atom on the pyrite surface containing S-vacancy, and the calcium atom bonds with the sulphur atom around the Fe-vacancy, which enhances the adsorption of calcium on the pyrite surface.