3D-printed ZSM-5 monoliths with metal dopants for methanol conversion in the presence and absence of carbon dioxide

Abstract

The development of effective strategies to utilize CO2 as a renewable feedstock for producing commercially-viable products is an interesting challenge to explore new concepts and opportunities in catalysis and industrial chemistry. In this study, 3D-printed ZSM-5 monoliths doped with Ga2O3, Cr2O3, CuO, ZnO, MoO3, and Y2O3were synthesized using the state-of-art 3D printing technique. The physicochemical properties of the catalysts were characterized by X-ray diffraction, N2 physisorption, NH3 and CO2 temperature-programed desorption and H2 temperature-programmed reduction. The promotional effect of doped metals on catalytic performance of 3D-printed ZSM-5 monoliths in methanol to hydrocarbon (MTH) reaction in the presence and absence of CO2 was investigated. Results indicated that both metal dopants type and reaction atmosphere greatly influence catalyst stability and product distribution. The yield of light olefins was enhanced over all metal-doped 3D-printed ZSM-5 monoliths in N2 atmosphere (absence of CO2), however, CO2 atmosphere did not favor the production of light olefins. Although selectivity toward ethylene slightly decreased, the propylene yield was almost constant after switching N2 to CO2 in MTH reaction at 400 °C. Furthermore, it was found that Y- and Zn-doped ZSM-5 monoliths exhibited higher yield of light olefins and BTX compounds in the in the absence and presence of CO2, respectively.