Carbon dioxide reforming of methane to synthesis gas over hexaaluminate ANiAl(11)O(19-delta) (A=Ca, Sr, Ba and La) catalysts

A series of A-modified hexaaluminates, ANiAl(11)O(19-delta) (A=Ca, Sr, Ba a nd La) as new catalysts for carbon dioxide reforming of methane to synthesi s gas, were prepared by decomposition of nitrates and calcination at high t emperature. Nickel ions as active component were inlayed in the hexaalumina te lattices to substitute part of Al ions. The structure and properties of these samples were characterized using XRD, XPS, TPR and TGA techniques. Th e series of hexaaluminates exhibited significantly catalytic activity and s tability at high temperature, for instance at 780 C-degrees for 18 h, the c onversion of CH4 and CO2 was kept over 91.0 and 93.7%, respectively, meanwh ile no Ni sintering, phase transformation and catalyst deactivation due to carbon deposition were found. Besides, the modifier A in the mirror plane l ayer of the lattices showed different effects on reducibility and catalytic activity of transition metal Ni in the hexaaluminate lattices.