HZSM-5 synthesized by montmorillonite and its application for production of hydrogen via steam reforming of dimethyl ether

HZSM-5 with different texture and acidity was prepared using sub-molten salt activated montmorillonite as raw material by traditional hydrothermal method, seed-directed method, steam-assisted crystallization method and aerosol crystallization method. And the HZSM-5 used as solid acid was physically mixed with commercial Cu/ZnO/Al₂O₃ to obtain bifunctional catalysts for steam reforming of dimethyl ether (SRD) reaction. The samples were systematically characterized by XRD, FT-IR, SEM, N₂ adsorption-desorption at low temperature, and NH₃-TPD techniques. The results showed that the crystal size, textural and acidity properties of HZSM-5 could be effectively regulated by the synthesis method, and then affecting the SRD performance of the corresponding bifunctional catalyst. TH-HZSM-5 synthesized by the traditional hydrothermal method exhibited suitable acid content and relatively large surface area, pore volume and pore size, and thus bifunctional catalyst composed of TH-HZSM-5 as solid acid and Cu/ZnO/Al₂O₃ with a mass ratio of 1∶1 showed better SRD reaction performance, and the dimethyl ether conversion and H₂ yield reached 100% and 91% under the conditions of reaction temperature 300 ℃, pressure 0.1 MPa, space velocity 5000 mL/(g·h), respectively.