The current paper presents a surface science study of the reaction pathways of thiophene on Ni/W(1 1 0) and Ni/Ru(0 0 0 1) surfaces. Using Auger electron spectroscopy (AES) and temperature-programmed desorption (TPD), we have shown that depositing Ni on a W(1 1 0) surface enhances the yield of the selective hydrodesulfurization (HDS) products, butene and butane. On Ni/W(1 1 0) surfaces with Ni coverages of 0.4 ML Ni, the butene product starts to desorb from the surface at similar to 178 K. In contrast, at Ni coverages above 2 ML, the butene product desorbs in two peaks at 209 and 259 K. When H-2 is pre-adsorbed on the Ni/W(1 1 0) surface, both butene and butane are detected at temperatures between 179 and 200 K on surfaces with Ni coverages between 0.3 and 0.5 ML Ni. For comparison, the Ni/Ru(0 0 0 1) surfaces also produce butene from the HDS of thiophene at temperatures below 300 K. However, pre-adsorbed hydrogen has only a relatively minor effect on the overall HDS activity of thiophene on the 1 ML Ni/Ru(0 0 0 1) surface. (C) 2003 Elsevier B.V. All rights reserved.