Catalysis Today 195 (2012) 93–100 Contents lists available at SciVerse ScienceDirect Catalysis Today jou rn al h om epage: www.elsevier.com/locate/cattod Biogas reforming for syngas production over nickel supported on ceria–alumina catalysts O.A. Bereketidou a,b , M.A. Goula a,∗ a Technological Educational Institute of Western Macedonia, Pollution Control Technologies Department, GR-50100 Koila, Kozani, Greece b University of Western Macedonia, Department of Mechanical Engineering, Bakola and Sialvera, GR-50100 Kozani, Greece a r t i c l e i n f o Article history: Received 13 January 2012 Received in revised form 10 July 2012 Accepted 10 July 2012 Available online 13 August 2012 Keywords: Biogas reforming Nickel catalysts Syngas production Ceria–alumina a b s t r a c t A series of 8 wt% nickel catalysts supported on alumina and alumina-modified with different amounts of ceria were prepared. The effect of the supporting ceria loading at the catalytic performance for the biogas reforming reaction was investigated. The physicochemical properties of the final catalysts were determined by using different techniques: N 2 adsorption–desorption isotherms, X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and transmission electron microscopy (TEM). Catalytic performance was evaluated for the biogas reforming reaction using a feed gas mixture of CH 4 /CO 2 = 1.5, simulating a clean model of biogas. It was shown that nickel catalysts supported on ceria–alumina exhibit slightly higher conversion values, compared to the one supported on alumina above 800 ◦ C, which can be mainly attributed to the redox properties of ceria. In particular, the 8 wt% nickel catalyst supported on 20 wt% ceria–alumina was proven to have the best catalytic performance with a highest H 2 /CO ratio of about 1.3. The biogas reforming reaction catalyzed by nickel–alumina doped with ceria catalysts seems to be an appropriate process in order to produce syngas suitable for methanol or Fischer–Tropsch synthesis reactions, which require H 2 /CO ratio values between one and two (1 to 2). © 2012 Elsevier B.V. All rights reserved. 1. Introduction Global climate change caused by CO 2 emission is currently debated around the world and greener sources of energy are being sought as alternatives to the use of fossil fuels. Biogas is a clean and environmental friendly fuel that is typically generated from anaerobic degradation of biomass. Biogas, consisting mainly of CO 2 and CH 4 , is an attractive renewable carbon source and its exploitation would be advantageous from both financial and envi- ronmental points of view [1]. A clean model biogas consists mainly of 55–65% methane (CH 4 ), and 30–45% carbon dioxide (CO 2 ) [2]. The technologies that could be applied for biogas reforming reac- tion are the same that have been extensively used for the natural gas reforming: Steam Reforming (SRM), Partial Oxidation (PROX), Dry and Autothermal Reforming [3]. For syngas production, the CO 2 reforming of CH 4 or Dry Reforming of Methane (DRM) reaction has been proposed as the most promising one. DRM has attracted considerable scientific interest in the past years, as it offers the pos- sibility of simultaneous removal of two inexpensive and abundant carbon containing sources, which are also greenhouse gases, and their transformation into useful chemical products. Moreover, the ∗ Corresponding author. Tel.: +30 2461068296; fax: +30 2461039682. E-mail addresses: oberek@kozani.teikoz.gr (O.A. Bereketidou), mgoula@kozani.teikoz.gr, mgoula@teikoz.gr (M.A. Goula). utilization of CO 2 as a feedstock for producing chemicals, pauses an interesting challenge in exploring new concepts and new opportu- nities for catalysis and chemical industry [4]. DRM appears to be advantageous when compared to the SRM and PROX as the hydrogen to carbon monoxide molar ratio of the produced syngas is close to one. This value is considered to be the most appropriate for Fischer–Tropsch and other synthesis reactions for the production of liquid hydrocarbons [5–7]. The network reactions that can be included in the dry reforming process are summarised as follows: CH 4 + CO 2 ↔ 2CO + 2H 2 CO 2 reforming (1) CO 2 + H 2 ↔ H 2 O + CO reverse water gas shift (2) CH 4 ↔ C + 2H 2 methane decomposition (3) 2CO ↔ C + CO 2 Boudouard reaction (4) C + H 2 O ↔ CO + H 2 carbon gasification (5) Due to the attention that the DRM process is receiving, major efforts are being expended in the development of new catalysts that will exhibit high activity towards synthesis gas formation, and be resistant to coking, as well as, displaying stable long-term oper- ation. Generally, noble metals catalysts have been reported to be less sensitive to coking than the nickel-based ones [8–15]. 0920-5861/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.cattod.2012.07.006