One-pot pyrolysis method to fabricate Co/N co-doped hollow mesoporous spheres with carbon/silica binary shells for selective oxidation of arylalkanes

Abstract

Hollow mesoporous silica spheres have an excellent application prospect in the field of catalysis due to high specific surface area, tunable pore size, structural stability and void-confinement effect. In this work, rasberry-like Co/N co-doped hollow mesoporous spheres with carbon/silica binary shells were synthesized by a facile one-pot pyrolysis method, and the catalysts with different properties can be obtained easily by adjusting the factors such as the pyrolysis temperature and the introduction approach of the active substance cobalt porphyrin. The results indicated that pyrolysis temperature could exert influence on the specific surface areas and defects of catalysts. Moreover, the active sites introduced through different ways played an important role in utilizing the enrichment effect of reactants originated from the void-confinement effect. As a result, the obtained catalysts showed remarkable activity and stability for selective oxidation of ethylbenzene under moderate reaction condition. Additionally, the optimal catalyst that achieved 95.9% ethylbenzene conversion and 99.3% acetophenone selectivity also exhibited outstanding catalytic performance for lots of arylalkanes. The superior performance was due to the large specific surface area and the well-dispersed active sites stabilized by the hollow structures with carbon/silica binary shells, which could maximize the enrichment of reactants to accelerate the reaction.