The compounds K(2)CO(3), KCl, Na(2)CO(3), CaCO(3), CaO, and MgO were tested as catalysts for steam gasification of coke from oil sands bitumen at atmospheric pressure and 600-800 degrees C. Catalysts were added to liquid vacuum residue prior to coke formation and directly to the coke solids. K(2)CO(3) and Na(2)CO(3) were most effective, giving nearly complete conversion at 800 degrees C in 30 min, regardless of whether they were added before or after coke formation. Ca and Mg compounds did not promote catalytic reactions, nor did they interact physically with the coke based on SEM and EDX analyses. KCl was effective, to a lower extent than K(2)CO(3) and Na(2)CO(3) only at higher temperatures (800 degrees C). The alkali metal compounds showed high mobility within the coke phase, which was consistent with their catalytic activities. (C) 2010 Elsevier Ltd. All rights reserved.