Highly efficient catalytic combustion of o-dichlorobenzene over three-dimensional ordered mesoporous cerium manganese bimetallic oxides: A new concept of chlorine removal mechanism

A series of three-dimensional (3D) ordered mesoporous cerium manganese bimetallic oxide catalysts (marked as CeMnX, X refers to the molar percentage of Mn relative to total molar quantity of Ce and Mn) were prepared using KIT-6 as hard template. The highly ordered mesoporous structural CeMn30 had a large specific surface area where the formation of CeMnOx solid solution led to a great enrichment of Ce3+, oxygen vacancies, active oxygen species and acidic sites, which promoted the catalytic activity of CeMn30. CeMn30 exhibited a good stability which activity did not decrease after five cycles of activity test and o-dichlorobenzene conversion kept over 95% at 370 degrees C for more than 1600 min. The deactivation of CeMn30 used in stability test mainly caused by adsorption of inorganic chlorine species which are hardly to be removed completely by simple calcination process in air condition. CeMn30 also had a good water resistance and high airspeed applicability. In this work, the selectivity of HCl and CO2 can reach 100% at 347 degrees C and the chlorine dissociated from o-dichlorobenzene as a form of HCl without any Cl-2 produced which is an inevitable product of Deacon Reaction. Thus, the mechanism of chlorine removal from o-dichlorobenzene molecule is different from general cognition (Deacon Reaction). Based on this, we introduced a new and reasonable reaction mechanism in conjunction with a series of characterization analysis.