Alkali-resistant Ni/SiO(2)-Sil-1 and Ni/Al(2)O(3)-Sil-1 core-shell catalysts were prepared for use in direct internal reforming molten carbonate fuel cell (DIR-MCFC). A thin zeolite shell was grown on the surface of catalyst beads to create a diffusion barrier against alkali poisons in the vapors generated from the electrolyte during DIR-MCFC operation. The synthesis of low defect zeolite shell was investigated and the effects of shell thickness on catalyst activity were examined. A mathematical model of the reaction and alkali-poisoning was developed and the optimum zeolite shell thickness was determined. The experimental and modeling results demonstrated that the core-shell catalyst is more resistant to alkali poisoning and a zeolite shell thickness of 3.5 mu m can protect the catalyst for at least 100 h following a failure of the anode barrier in DIR-mCFC to give sufficient time for repair. (C) 2011 Elsevier B.V. All rights reserved.