Insight into Ce Doping Induced Oxygen Vacancies over Ce-Doped Mno₂ Catalysts for Imine Synthesis

The pursuit of modern sustainable chemistry has stimulated the development of innovative catalytic processes that enable chemical transformations to be performed under mild and clean conditions with high efficiency. Here, an amorphous sheet-like MnO₂ (Ce-doped MnO₂: CMBO) was obtained after Ce doping, which exhibits excellent catalytic performance for the oxidation coupling of alcohol and aniline. Conversion of 99% and a selectivity of 99% could be achieved within 6 h at 60 ^oC under air atmosphere, and the formation rate of target product was up to 30.2 μmol·h^–1·m^–2. Based on a series of characterizations, it was found that the doping of Ce into the MnO₂ could increase the concentration of the oxygen vacancies, thus forming abundant active surface oxygen species and favoring the mobility of lattice oxygen, which are the main reasons for the greatly enhanced catalytic performance of CMBO. This work indicates that increasing oxygen vacancy by element doping may serve as a facile and efficient way to enhance catalytic performance of transition metal oxide.