In situ XRD investigation of Со_3O_4 reduction

摘要

In situ X-ray diffraction (XRD) method was used to investigate the Co_3O_4reduc-tion in catalyst supported on γ-Al_2O_3and oxide monophase sample. Initial structure of Co_3O_4in both samples is similar and contains vacancies in the cation positions. In spite of this re-duction process of Со_3O_4is different for supported and monophase samples as has beenshown by in situ XRD. In monophase sample the cobalt oxide is reduced to metallic cobalt(hcp) directly. On the contrary the two-stage reduction is observed for supported sample:Со_3O_4is reduced to CoO and then to metallic Co (fcc). In both cases nanoparticles of metal-lic cobalt contains high concentration of stacking faults.