Journal of Power Sources 171 (2007) 811–817 Regeneration of an n-decanethiol-poisoned nickel catalyst H. Oudghiri-Hassani a , N. Abatzoglou a,∗ , S. Rakass a , P. Rowntree b a Department of Chemical Engineering, Universit´ e de Sherbrooke, 2500 Boul. Universit´ e, Sherbrooke, Quebec, Canada b Department of Chemistry, University of Guelph, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1 Received 11 May 2007; received in revised form 25 June 2007; accepted 26 June 2007 Available online 10 July 2007 Abstract The regeneration of an n-decanethiol-poisoned nickel catalyst by treatment with steam was studied using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray photoemission spectroscopy (XPS) and mass spectrometry (MS). The catalytic activity of a Ni catalyst contaminated with n-decanethiol (H (CH 2 ) 10 SH) before and after regeneration was measured on methane steam reforming at a CH 4 :H 2 O ratio of 1:2 at 700 ◦ C and compared to the nickel catalyst. The results show that, although (a) in the regenerated catalyst surface there is no residual sulfur and (b) the amount of surface carbon is the same as in Ni catalyst, the regenerated catalyst has gained 84% of its catalytic activity. Since all sulfur is removed, this loss of activity is attributed to structural changes at the surface of the catalyst and to the different nature of the remaining carbon. © 2007 Elsevier B.V. All rights reserved. Keywords: Regeneration; Steam reforming; Ni catalyst; Sulphur poisoning; XPS; IR 1. Introduction Nickel continues to be both a well established and a promising new material in several developing fields of applied technology such as those arising in catalysis and in fuel cells [1,2]. For example, steam reforming, long used in the manufacture of syn- thesis gases and pure hydrogen from hydrocarbons, is a catalytic process involving ceramic-supported nickel catalysts. Coke for- mation [3–10] and sulfur poisoning [3,5,9,11,12] are two of the major problems associated with nickel catalysts. The presence of sulfur collecting on a catalyst surface is known to cause sub- stantial losses of the catalyst’s activity in many desired reactions, particularly those utilized in methane steam reforming processes [3]. This loss of activity is due to (1) direct sulfur adsorption on nickel particle surface(s) which hinders further adsorption of the reactant molecules and (2) the reconstruction of the Ni surfaces (i.e. sulfur can modify the chemical nature of the active Ni sites or result in the formation of new compounds which may modify or decrease the adsorption rates of reactant gases). The presence of carbon on catalyst surfaces can also cause (a) the blockage of desirable catalyst pores, (b) the loss of structural integrity of ∗ Corresponding author. Tel.: +1 819 821 7904. E-mail address: Nicolas.Abatzoglou@USherbrooke.ca (N. Abatzoglou). the catalyst support material [3,5,6,8] and (c) fouling of the cat- alysts surfaces. Catalyst deactivation may be overcome, at least partially, through timely regeneration processing. Relatively few studies, on the regeneration of sulfur-poisoned and carbon-poisoned catalysts, have been reported in the liter- ature. In the case of sulfur deposits, the following processes have been studied for their efficiency in the removal of sul- fur from poisoned nickel catalysts and the restoration of their activity: (a) reduction with hydrogen [12,13] and (b) mild con- ditions oxidation, with oxygen or water [14,15]. The final goal is the removal of surface sulfur through H 2 S or SO 2 forma- tion. Efforts made to regenerate sulfur-poisoned Ni catalysts, using H 2 [15–17] alone, have been largely unsuccessful. One US Patent [18] proposes the use of H 2 to regenerate 15–60% Ni/Al 2 O 3 at 700–1100 K, although reportedly, no sulfur is actu- ally removed by this treatment. In respect of the study of regeneration using steam reaction, Rostrup-Nielsen [19] have reported that up to ∼80% removal of the surface sulfur from Ni can be achieved at 700 ◦ C, being either promoted or unpro- moted by Mg and Ca, steam reforming catalysts. Aguinaga [13] had studied the regeneration of a nickel/silica catalyst, poisoned by thiophene, through oxidation–reduction treatments use, and they report that the sulfur removal efficiency of these methods is as high as 90% when they are applied to completely deactivated catalysts. 0378-7753/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2007.06.258