Manganese oxide hollow structures with different phases: Synthesis, characterization and catalytic application

Manganese oxide hollow structures with different phases were synthesized by calcination using a γ-MnO2 hollow structure as a precursor. Our results revealed that the as-synthesized β-MnO2 and Mn2O3 still maintained the morphology of the precursor. Compared with the MnO2 reported and conventional MnO2, both the γ-MnO2 and β-MnO2 hollow structures showed a higher catalytic activity and an excellent selectivity in the aerobic oxidation of cinnamyl alcohol to cinnamyl aldehyde. The TPR experiments demonstrated that the reduced size of crystallite, hollow nature and higher BET specific surface area were responsible for their higher catalytic activity.