Insight on the role of a new heterogeneous catalyst for catalytic steam gasification of adsorbed asphaltenes is reported. The catalyst was prepared by incorporating NiO nanoparticles into mesoporous-macroporous Ba-based meta kaolin intended both as catalyst support as well as adsorbent. Variations on the catalyst support were made in form of extrudates by adding a binder (Ba(CH3COO)(2) and/or Ca(CH3COO)(2)) and sucrose as a porogenic substance, to kaolin and calcining in air typically at 650 degrees C. Effect of the binder type and content, sucrose content and calcination temperature upon adsorption was determined by performing adsorption study of Quinoline-65 (Q-65) using UV-Vis spectrophotometry. The surface basicity of catalyst support was measured by CO2 temperature programmed desorption (TPD) experiments. Pore size distribution was determined by Nitrogen physisorption. The Q-65 uptake was correlated to the pore size distribution and the basicity of the adsorbents. The results suggest that solids having low surface basicity and with increased pore size distribution between 200 and 800 angstrom showed better adsorption. Further, incorporation of NiO nanoparticles into these catalyst supports not only enhanced the adsorption of asphaltenes, but also promoted the steam gasification of the adsorbed asphaltenes, leading to CO2 and H-2 as major products. (C) 2012 Elsevier B. V. All rights reserved.