Study on the Reduction Behavior of Molybdenum Oxide (MoO3) in Carbon Monoxide (CO) Atmosphere

The reduction behavior of molybdenum trioxide (MoO3) by carbon monoxide (CO) has been studied using temperature programmed reduction (TPR) and was characterized using X-ray diffraction spectroscopy (XRD). The TPR result shows that the first reduction peak of MoO3 under 20 vol. % CO in nitrogen started at 530 °C and second reduction peaks observed was at 700 °C. The XRD technique was employed to identify the changes in the sample. It was found that after non-isothermal reduction up to 700 °C, the intermediate phases Mo4O11 were observed. Completed reduction to MoO2 achieved after continued reduction with isothermal mode at 700 °C for 60 minutes. Based on the XRD analysis, it is confirmed that the reduction of MoO3 to MoO2 in CO atmosphere consists of two reduction stages, i) Mo6+ → Mo5+ and ii) Mo5+ → Mo4+. While, CO excess have resulted the formation of molybdenum carbide (Mo2C) rather than formation of metallic molybdenum (Mo).