Alkali resistant Ni-loaded yolk-shell catalysts for direct internal reforming in molten carbonate fuel cells

A facile and scalable spray pyrolysis process is applied to synthesize multi-shelled Ni-loaded yolk-shell catalysts on various supports (Al₂O₃, CeO₂, ZrO₂, and La(OH)₃). The prepared catalysts are applied to direct internal reforming (DIR) in a molten carbonate fuel cell (MCFC). Even on exposure to alkali hydroxide vapors, the Ni-loaded yolk-shell catalysts remain highly active for DIR-MCFCs. The Ni@Al₂O₃ microspheres show the highest conversion (92%) of CH₄ and the best stability among the prepared Ni-loaded yolk-shell catalysts. Although the initial CH₄ conversion of the Ni@ZrO₂ microspheres is higher than that of the Ni@CeO₂ microspheres, the Ni@CeO₂ microspheres are more stable. The catalytic performance is strongly dependent on the surface area and acidity and also partly dependent on the reducibility. The acidic nature of Al₂O₃ combined with its high surface area and yolk-shell structure enhances the adsorption of CH₄ and resistance against alkali poisoning, resulting in efficient DIR-MCFC reactions.