Abstract—The reduction of undoped tungsten oxide (WO
3) and doped tungsten oxide has been studied by using temperature programmed reduction (TPR) and characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and transmission electron microscope (TEM) analysis. Zirconia (Zr) and nickel (Ni) doped tungsten powder were prepared by impregnation method. The effect of Zr and Ni doping on reduction of WO
3 and the effect of holding time on reduction were also studied. The reduction behavior were examined by nonisothermal reduction up to 900 °C then continued with isothermal reduction at 900 °C for 45 min under (40 %v/v) carbon monoxide in nitrogen (CO in N
2) atmosphere. The results show that, TPR spectra of doped powder slightly shift to a lower temperature (ºC) as compared to the undoped WO
3 . The reduction steps involved in the undoped WO
3, 10 mol% Zr and 10 mol% Ni to WO
3 were found WO
3 → WO
2 and
W, WO
3 → W
O
2, W and W
2C and WO
3 →WC and Ni0.98C0.02 respectively. The ca
rbide formation from reduction WO3 in th
is study revealed that WO
2 and W could transform to carbide in excess of CO introduction. The ability to enhance the reducibility involved in WO
3 may associate to the presence of zirconium tungsten (Zr(WO
4 )
2) compound and nickel tungsten oxide (NiWO
4).
Index Terms—Carbon monoxide, nickel, tungsten, tungsten oxide, zirconia.
The authors are with the School of Chemical Science & Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia (e-mail: fairoussalleh@gmail.com, tengkushafazila@gmail.com, alindasamsuri@gmail.com, rizafizah@ukm.edu.my, ambar@ukm.edu.my).
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Cite: Fairous Salleh, Tengku Shafazila Tengku Saharuddin, Alinda Samsuri, Rizafizah Othaman, and Mohd. Ambar Yarmo, "Effect of Zirconia and Nickel Doping on the Reduction Behavior of Tungsten Oxide in Carbon Monoxide Atmosphere," International Journal of Chemical Engineering and Applications vol. 6, no. 6, pp. 389-394, 2015.
