The presence of gallium on HZMS5 zeolites increases the rate of coke elimination in their regeneration in hydrogen. The gallium species should contribute to the hydrogenation of the coke molecules and the acid sites should favour their crackings. However, the location of the coke molecules (near the outer surface and near the gallium species) instead of their nature seems to be the determining parameter for their elimination
Ga/HZSM5 catalysts; coke; regeneration in hydrogen
