Characteristics of alkali-resistant Ni/MgAl2O4 catalyst for direct internal reforming molten carbonate fuel cell

Direct internal reforming – molten carbonate fuel cell (DIR–MCFC) has advantages of higher efficiency and smaller size. However, deactivation of the catalyst by alkali carbonate electrolytes poses a significant problem in MCFC. To solve this problem, Ni/MgO and Ni/MgAl2O4 catalysts were compulsively mixed with a eutectic mixture of Li2CO3 and Na2CO3 prior to a methane steam reforming activity test. Activity of Ni/MgO rapidly decreased, while that of Ni/MgAl2O4 remained steady due to good alkali resistance. To analyze the effects of alkali addition, N2 adsorption-desorption, X-ray diffraction, temperature-programmed reduction and oxidation, scanning electron microscopy, and X-ray photoelectron spectroscopy experiments were carried out. Both Ni/MgO and Ni/MgAl2O4 showed sintering of Ni and blocking of pores, which reduced the catalytic activity. However, Ni/MgAl2O4 showed other positive effects such as stronger metal–support interaction and increased dissociative adsorption.