Effect of transition metals addition on the nickel oxide catalyst toward reduction behaviour in carbon monoxide atmosphere

• Main Authors: Dzakaria, Norliza, Lahuri, Azizul Hakim, Salleh, Fairous, Tengku Saharuddin, Tengku Shafazila, Samsuri, Alinda
• Format: Article
• Published: Penerbit Universiti Putra Malaysia 2023
• Subjects: Metal ions; atmosphere; Atmospheric temperature
• Online Access: http://psasir.upm.edu.my/id/eprint/105914/; http://www.pertanika.upm.edu.my/pjst/browse/regular-issue?article=JST-3779-2022; https://doi.org/10.47836/pjst.31.4.07

The chemical reduction progression behaviour of transition metals (Mo, Zr, W, Ce, and Co) doped on NiO was studied using temperature programmed reduction (TPR) analysis. A wet impregnation method was applied to synthesise the doped NiO series catalysts. The reduction progress of the catalysts was attained by using a reductant gas at the concentration of 40% v/v CO/N2. X-ray diffraction (XRD) was employed to determine the composition of the reduced phases. Undoped NiO was reduced at 384℃ to obtain a cubic phase of NiO. It was observed that Ce/NiO exhibited the lowest reduction temperature of 370℃ among all catalysts. This phenomenon might be due to a higher surface area of Ce/NiO compared to undoped NiO, which facilitated a faster reduction reaction. The rest of the doped NiO series catalysts (Co/NiO, Mo/NiO, W/NiO and Zr/NiO) demonstrated a higher reduction temperature compared to undoped NiO. New peaks in the XRD pattern were observed only for the reduced catalysts of Mo/NiO and W/NiO, which were associated with monoclinic MoO2 and WO2.72 phases, respectively. The formation of new compounds or more stable nickel alloys led to a slower reduction reaction than undoped NiO. Therefore, Ce/NiO was the most efficient catalyst in promoting the formation of Ni under the CO atmosphere.