“…The absorption at 459 cm –1 is related to the silanol bending, and the vibration of asymmetric and symmetric stretching vibrations of Si–O–Si are assigned to the bands at 1084 and 801 cm –1 , respectively. − These characteristics also indicated the retention of the original structure, meaning the prepared bifunctional catalysts can preserve the merits of the mesoporous silica supports. Meanwhile, a band at 969 cm –1 for the obtained samples could be explained as the framework Si–O–M vibrations, reflecting the incorporation of the metal species into the silica framework. , The band at 1647 cm –1 corresponded to the hydroxyl deformation mode on the material surface …”