CH4/H2气氛中Ni-Mo双金属氧化物还原碳化 过程的TG-DTA研究

 采用TG-DTA技术研究了MoO3在CH4/H2气氛中的还原碳化行为，考察了NiO助剂对MoO3还原碳化性能的影响，探索了适宜的还原碳化条件。结果表明，MoO3在H2气氛中程序升温还原经MoO3 → MoO2 →Mo反应历程被还原为金属Mo，在CH4/H2气氛中则经MoO3→MoO2→MoOxCy →Mo2C反应历程被还原碳化成Mo2C；NiO可在H2气氛中被还原成金属Ni，但在CH4/H2气氛中不能被碳化成相应的碳化物,也被还原为金属Ni；NiO作为助剂添加到MoO3中后，NiO-MoO3在CH4/H2气氛中的还原碳化反应历程为NiO-MoO3→Ni-MoOxCy→ Ni-Mo2C，相应的还原碳化温度降低。随Ni/Mo原子比的增大，制备的NiO-MoO3在CH4 /H2气氛中还原碳化的温度降幅增大。MoO3 和NiO-MoO3的适宜还原碳化温度分别为675℃和639℃。

STUDY ON CARBURIZING REACTION OF BIMATALLIC Ni-Mo OXIDE IN CH4/H2 MIXTURE BY TG-DTA

The carburizing reaction of MoO3 and influence of NiO promoter were investigated by TG-DTA in-situ in CH4/H2，and carburized samples were characterized by XRD techniques. The results indicated that in the temperature-programmed reaction(TPR) with H2 as the reducing atmosphere MoO3 was reduced to metal Mo through the pathway of MoO3 → MoO2 →Mo, and in the temperature-programmed reaction(TPR) with CH4/H2 mixture as the reducing atmosphere MoO3 could be reduced to Mo2C by the pathway of MoO3→MoO2 →MoOxCy→Mo2C. NiO could be reduced to metal Ni by TPR in H2, but not be carburized to nickel carbide in CH4/H2 mixture. It was found that the carburizing reaction pathway of NiO-MoO3 was NiO-MoO3→Ni-MoOxCy→Ni-Mo2C in CH4/H2 mixture, and its carburizing temperature decreased with the increase of Ni/Mo atom ratio. The proper carburizing temperature of MoO3 and NiO-MoO3 was 675℃ and 639℃, respectively.