Hierarchical ZSM-5 catalyst synthesized by a Triton X-100 assisted hydrothermal method

ZSM-5 zeolite with a hexagonal cubic morphology was synthesized by a hydrothermal method using Triton X-100, a nonionic surfactant. The samples prepared with and without the surfactant were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, N2 adsorption, high resolution transmission electron microscopy (TEM), high resolution scanning electron microscopy, energy dispersive X-ray analysis, and NH3 temperature-programmed desorption. The XRD patterns confirmed the formation of a pure ZSM-5 crystalline phase without secondary phases. TEM images revealed that the hexagonal cubes were made of peanut-shaped nanoparticles with voids. The catalytic activity of the zeolite samples was evaluated using the selective oxidation of benzyl alcohol with tertiary-butyl hydrogen peroxide as the oxidant at 90 °C. The surfactant-assisted preparation yielded a zeolite that gave a higher conversion than the one prepared in the absence of the surfactant. The catalyst was retrieved and reused four times without significant loss in activity and selectivity.