In situ high-temperature X-ray diffraction studies of reduction of K2CrO4 and the formation of KxCrOy compounds. Issue 3 (3rd July 2017)

• Record Type: Journal Article
• Authors: Liang, Shu-ting; Zhang, Hong-ling; Luo, Min-ting; Bai, Yu-lan; Xu, Hong-bin; Zhang, Yi
• Is Part Of: Powder diffraction. Volume 32:Issue 3(2017)
• Page Start: 168
• Page End: 174
• Publication Date: 2017-07-03
• Subjects: in situ XRD, -- in situ FTIR, -- K2CrO4, -- reduction mechanism, -- activated KxCrOy; Powder metallurgy -- Periodicals; Materials -- Analysis -- Periodicals; 620.1127
• DOI: 10.1017/S0885715617000690
• Languages: English
• ISSNs: 0885-7156

Abstract

Abstract : In this work, the reduction mechanism of potassium chromate (K2 CrO4 ) was investigated via in situ high-temperature X-ray diffraction coupled with Fourier transform infrared spectroscopy. During the hydrogen reduction of K2 CrO4, the formation of K3 CrO4, KCrO2, and K x CrO2 were detected for the first time. The study discovered that K2 CrO4 was firstly reduced to K3 CrO4 and an amorphous Cr(III) intermediate product at low temperature (400–500 °C). Moreover, the K3 CrO4 was the only crystalline material at this stage. As the temperature increased, a stabilized amorphous CrOOH was formed. At a high temperature (550–700 °C), KCrO2 was generated. Interestingly, a portion of KCrO2 was spontaneously decomposed during the hydrogen reduction, accompanying by the formation of K0.7 CrO2 . Finally, the results clearly illustrated the reduction mechanism of K2 CrO4 : K2 CrO4 → K3 CrO4 → amorphous intermediate → KCrO2 .