Preparation of core (Ni base)–shell (Silicalite-1) catalysts and their application for alkali resistance in direct internal reforming molten carbonate fuel cell

Alkali-resistant Ni/SiO2–Sil-1 and Ni/Al2O3–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 μm 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.

Thin Sil-1 zeolite shells were grown on the surface of Ni–SiO2 and Ni–Al2O3 catalyst beads to prepare nickel-zeolite core–shell catalysts with excellent resistance to alkali poisoning in DIR-MCFC. Experiments and model calculations were used to determine the optimum shell thickness capable of protecting the catalyst for at least 100 h following failure of anode barrier in DIR-MCFC.Figure optionsDownload as PowerPoint slideHighlights
► Core–shell catalysts with thin zeolite shell were designed and prepared to resist alkali poisoning in DIR-MCFC.
► Nickel and nickel-zeolite core shell catalysts performance were investigated and a mathematical model for catalyst reaction and deactivation was obtained.
► Ni/Al2O3–Sil-1 core–shell catalyst performed best among the catalysts examine.
► An optimum shell thickness was predicted by model calculation that could sustain at least 100 h operation following damage in DIR-MCFC anode barrier.