Nickel Oxide Based Supported Catalysts for the In-situ Reactions of Methanation and Desulfurization in the Removal of Sour Gases from Simulated Natural Gas Wan Azelee Wan Abu Bakar Æ Mohd Yusuf Othman Æ Rusmidah Ali Æ Ching Kuan Yong Received: 6 August 2008 / Accepted: 24 September 2008 / Published online: 11 November 2008 Ó Springer Science+Business Media, LLC 2008 Abstract Supported nickel oxide based catalysts were prepared by wetness impregnation method for the in-situ reactions of H 2 S desulfurization and CO 2 methanation from ambient temperature up to 300 °C. Fe/Co/Ni (10:30:60)–Al 2 O 3 and Pr/Co/Ni (5:35:60)–Al 2 O 3 catalysts were revealed as the most potential catalysts, which yiel- ded 2.9% and 6.1% of CH 4 at reaction temperature of 300 °C, respectively. From XPS, Ni 2 O 3 and Fe 3 O 4 were suggested as the surface active components on the Fe/Co/ Ni (10:30:60)–Al 2 O 3 catalyst, while Ni 2 O 3 and Co 3 O 4 on the Pr/Co/Ni (5:35:60)–Al 2 O 3 catalyst. Keywords Nickel oxide  Catalyst  Methanation  Desulfurization  Natural gas 1 Introduction Malaysian crude natural gas is categorized as a sour gas due to the contamination of carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S). Catalysts for the CO 2 methanation have been extensively studied because of their application in the conversion of CO 2 gas to produce methane, which is the major component in natural gas. In fact, there is also presence of H 2 S in real natural gas. Therefore, H 2 S should be considered in invention of methanation catalyst, since it could cause poisoning of the nickel catalyst. However, fewer researches on the catalyst for in-situ reactions of CO 2 methanation and desulfurization have been carried out. The acidic nature of CO 2 and H 2 S necessitates the employment of a catalytic system with basic properties such as Group VIII metals. According to Miao et al. [1], the activity and selectivity of the catalysts are most probably related to the changeable valence of M 0 /M 2? . The major reasons for the much slower development of the catalysts science of mixed metal oxide is its signifi- cant complexity compared with metal based catalysts e.g. possible presence of multiple oxidation states, variable local coordination, coexisting bulk and surface phases as well as different surface termination functionalities such as M–OH, M = O or M–O–M [2]. Nickel based catalysts are generally considered as reference methanation cata- lysts and proven to eliminate H 2 S by desulfurization process. According to Inui et al. [3], the CO 2 methanation activity of the nickel based composite catalyst from the substrates of iron group metals following this order: Ni [ Co [ Fe. El-Shobaky et al. [4] observed a signifi- cant increment in the catalytic activity of NiO/MgO system due to treatment with small amount of CoO. Souma et al. [5] investigated that methanation reaction seems to be accelerated by the absorption of H 2 on metallic Ni or Co. Medina et al. [6] concluded that carbon dioxide hydrogenation on Fe has the advantage of no catalyst deactivation. Praseodymium has been investigated as the most effective rare earth metal oxide when it was doped onto NiO based catalysts for CO 2 methanation reaction at 400 °C. Later, cobalt oxide was found as the most suitable dopant towards the Pr/Ni catalyst (WA Wan Abu Bakar, ‘‘Personnel Communication’’ 2005). The addition of increasing amounts of Pr 6 O 11 caused the conversion rate of side product to decrease with an apparent minimum [7]. The selection of support is con- sidered as important since it may influence both the activity and selectivity of the reaction. It has been W. A. Wan Abu Bakar (&)  M. Y. Othman  R. Ali  C. K. Yong Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia e-mail: wanazelee@yahoo.com 123 Catal Lett (2009) 128:127–136 DOI 10.1007/s10562-008-9703-2