Effects of RE2O3 doping on the reduction behavior of molybdenum oxide and properties of molybdenum powder

The reduction of molybdenum oxide doped with rare earth oxides (RE2O3) and the properties of molybdenum powder with RE2O3 additions have been studied by TG-DTA, X-ray diffraction, temperature programmed reduction (TPR), and X-ray photoelectron spectrometry (XPS). The TPR results show that the reduction peak of doped MoO3 shifts to lower temperature as compared with that of pure MoO3. The interaction between rare earth and molybdenum ions leads to this decrease of the reduction temperature of RE2O3 doped molybdenum oxide. RE2O3 is decreasing the particle size of molybdenum by the pinning effect of RE2O3 at the molybdenum grain boundaries. Moreover, RE2O3 nanoparticles on the surface of molybdenum powder increase the escape depth of free electrons in molybdenum, decrease the height of the characteristic energy loss peak of molybdenum, and thus increase the height of the XPS-Mo3d peak.