Nickel loading on the isothermal carburation of molybdenum trioxide catalyst.

The carburization behaviour of nickel molybdenum trioxide (Ni-MoO₃) catalyst with different loading of Ni has been studied by using temperature programmed reduction (TPR) with exposure of 60 vol. % CO in 40 vol. % helium as a reductant. The Ni-MoO₃ catalysts were prepared by using the conservative wet impregnation method. The carburization characteristics of prepared catalysts were examined by isothermal carburization mode at 700°C for 90 minutes. The carburized phases were characterized by using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and field emission scanning electron microscopy (FESEM). XRD pattern for undoped MoO₃ show the formation of molybdenum dioxide (MoO2) (2θ=37° and 74.10°) and Mo₂C (2θ=33.63° and 62.50°). After addition of nickel at higher loading which is 3% (wt./wt.) of Ni-MoO₃ show the XRD pattern obtained Mo₂C at at 2θ=61.47°. This is showing that the higher loading of nickel in MoO₃ lead to higher reducibility compared 1% (wt./wt.) of Ni-MoO₃ but the broad and weak peak resulted from XRD pattern. By calculating the crystallites size 7.11 nm for 3% (wt./wt.) Ni-MoO₃ catalyst give the higher crystallinity compared to 1% (wt./wt.) Ni-MoO₃ catalyst which is 5.70 nm. Physical analysis by using BET showed an increasing in surface area and pore size of MoO₃ catalyst after addition of Ni metal loading. This proves that the higher the addition of loading might attribute to the increasing in active site for enhancing the carburization process which lead to the formation of Mo₂C. The slightly phase covering the surface of the particles or seemed like an agglomerate is amorphous deposited carbon that formed between the platelet shape on Ni-MoO₃ surfaces were observed through the FESEM images indicating some morphology modification occurred on MoO₃. Based on these results, it is interesting to address that the addition of Ni metal to MoO1₃ has a remarkable influence in carburization process. The 3% (wt./wt.) of Ni on MoO₃ catalyst was sufficient to promote the formation of Mo₂C. [ABSTRACT FROM AUTHOR]