pH值对水热合成黄铁矿型CoS2微晶的影响

本文以EDTA-2Na为辅助剂,Na2S2O3.5H2O为硫源,运用水热法制备了黄铁矿型CoS2微晶,研究了溶液pH值对产物结构和形貌的影响。采用X射线粉末衍射仪(XRD),扫描电子显微镜(SEM)对产物的结构和形貌进行了表征。实验结果表明,溶液为酸性环境时(pH=1、3)可得到纯相的黄铁矿型CoS2微晶,形貌为微米尺寸的空心球壳。溶液为中性和碱性环境时(pH=7、11),产物出现少量杂相,形貌变为规则的八面体晶粒。讨论了这些CoS2微晶的形成机制。

Effects of pH Value on Hydrothermal Synthesis of Pyrite CoS2 Micro-Crystals

Pyrite CoS₂ micro-crytals were synthesized under hydrothermal conditions employing sodium thiosulfate pentahydrate (Na₂S₂O₃·5H₂O) as sulfur source and ethylenediaminetetraacetic acid disodium (EDTA-2Na) as assistant. The effects of pH value of solution on the structures and morphologies of the products were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the structural features and the morphology of the samples. The results show that the morphologies of the products could be tuned by the pH values of solutions. The pure-phase pyrite CoS₂ micro-crystals with regular hollow sphere-like morphology can be obtained in acid environment (pH=1, 3), while well-faceted octahedron-shaped CoS₂ micro-crystals were synthesized in neutral and alkaline environment (pH=7, 11). The mechanisms for the formations of the CoS₂ micro-crystals were discussed.