Structure and catalytic properties of K-doped manganese oxide supported on alumina

In this study, we reported a remarkably improved catalytic activity of Mn/γ-Al2O3 catalyst promoted with potassium doping in the selective oxidation of benzyl alcohol with molecular oxygen. Characterizations of powder X-ray diffraction (XRD), Raman spectroscopy, X-ray absorption fine structure (XAFS), and hydrogen temperature-programmed reduction (H2-TPR) revealed that the co-impregnation of potassium to the Mn/γ-Al2O3 gave rise to the presence of α-MnO2 rather than β-MnO2, resulting in a stable catalyst with enhanced catalytic performance. We also demonstrated this alumina-supported K–Mn mixed oxide catalyst can effectively catalyze aerobic oxidation of various aromatic alcohols.

Graphical abstractDoping potassium to the Mn/γ-Al2O3 gave rise to the presence of α-MnO2 rather than β-MnO2, which resulted in a particularly active manganese species to catalyze the aerobic oxidation of various aromatic alcohols in the presence of molecular oxygen. The low onset reduction of supported α-MnO2 is suggested to be the vital factor for the activation of molecular oxygen.Figure optionsDownload full-size imageDownload high-quality image (132 K)Download as PowerPoint slide