Abstract
Thermoactivated Ni-exchanged AlMCM-41 mesoporous materials were found to be very efficient heterogeneous catalysts for the ethylene oligomerization. By means of DRIFT spectroscopy of adsorbed CO it has been established that during the thermal activation under dry atmosphere, the Ni2+ ions were partially reduced into Ni+ ions. A very good correlation between the activation temperature and the catalytic activity in the ethylene oligomerization was observed. Both Ni+ and dehydrated Ni2+ ions were proposed as catalytic active sites in this process.