Highly Dispersed Nickel Nanoparticles on Hierarchically Ordered Macroporous Al2O3 and Its Catalytic Performance for Steam Reforming of 1-Methyl Naphthalene

In this study, we investigate the effect of a hierarchically ordered macroporous structure of alumina support on the steam reforming of 1-methyl naphthalene with mesoporous alumina-supported nickel and potassium (xK/Ni-MeAl), and macroporous alumina-supported nickel and potassium (xK/Ni-MaAl) catalysts. Hierarchically ordered macroporosity in Al2O3 supports plays an important role in maintaining the high Ni dispersion through multiple interactions in Ni-K over AlO4 tetrahedra in alumina. This, in turn, improves the catalytic performance of steam reforming, including high gas yields, turnover frequency for hydrogen production, and 1-methyl naphthalene conversion. At high K content, the Ni active sites over xK/Ni-MeAl catalysts significantly decrease, resulting in almost zero steam reforming rate in the reaction test. Conversely, the potassium-alumina interaction in xK/Ni-MaAl catalysts not only diminishes the formation of the inactive nickel aluminate phase but also maintains the highly dispersed Ni active sites, resulting in a high steam reforming rate.