TEMPERATURE PROGRAMMED REDUCTION AND X-RAY DIFFRACTOMETRY STUDIES OF MoO 3 REDUCTION BY DIFFERENT CONCENTRATIONS OF CARBON MONOXIDE ( Kajian Penurunan

Reduction of molybdenum trioxide, MoO3 to molybdenum dioxide, MoO2 by using carbon monoxide, CO has been studied by temperature programmed reduction (TPR) and X-ray diffraction spectroscopy (XRD). The influence of carbon monoxide concentration on the reduction of MoO3 have been investigated by comparing the reduction behaviour of MoO3 to MoO2 with 20 vol.% and 40 vol.% of CO concentration. The XRD results show that by using 20% of CO, reduction to MoO2 takes place at 700°C in 60 minutes. However, by using 40% of CO, complete reduction to MoO2 takes place at 700°C in only 30 minutes. Moreover, excess of CO results in the formation of molybdenum carbide, Mo2C. It is suggested that by using CO, complete reduction from MoO3 to MoO2 gives two-steps reduction (MoO3 → Mo4O11 → MoO2) with Mo4O11 as an intermediate product. It can be concluded that the reducing behavior of MoO3 is strongly dependent on the concentration of CO and reaction time.