Synthesis and characterization of Co-SBA-15 via rapid ultrasonic technique and their catalytic properties.

The rapid preparation of SBA-15 with cobalt (Co) introduction was performed via the ultrasonic irradiation in combination with "pH-adjusting" method. The catalytic properties of the synthesized Co-SBA-15 were investigated by examining the oxidation of styrene with hydrogen peroxide. The effect of pH values on the textural properties were extensively investigated using small-angle X-ray Diffraction (XRD), N2 adsorption-desorption isotherms and Transmission Electron Microscipy (TEM). The characterization results showed that the incorporation of Co by ultrasonic method did not destroy the mesoporous structure of SBA-15. The Co-SBA-15 catalyst with Co/Si (the molar ratio of 0.03) at pH of 7.5 exhibited a well-ordered hexagonal mesoporous structure with higher surface area and pore volume. This catalyst had excellent styrene conversion and selectivity to benzaldehyde of 21.8% and 92.3%, respectively. The physicochemical properties and catalytic activity of the Co-SBA-15 catalysts via ultrasonic technique possessed the comparable characteristics as those prepared via conventional hydrothermal method.