LAUSR

Abstract Dimethyl ether (DME), a promising renewable energy source, has been extensively studied due to its inherent advantages. A cost-effective approach to synthesize ferrierite (ZSM-35) from geopolymer precursors was proposed in this study. The catalytic behavior of geopolymer-based ZSM-35 was evaluated in the process of methanol to dimethyl ether (MTD), and the acid sites, porosity and metal functions of catalysts were continuously optimized to improve the catalytic efficiency. The results showed that protonated catalysts were more active than original products due to their abundant weak acid, medium-strong and strong acid sites. The porosity was mainly affected by the structure of catalysts. The maximum conversion of methanol increased from 16% to 30% and then to 71%, corresponding to the conversion of amorphous geopolymer to semi-crystalline and finally to crystalline ZSM-35 zeolite. ZSM-35 zeolite was the optimal catalyst due to its SBET of 237.9 m2/g was higher than that of geopolymer of 9.3 m2/g, which provided more adequate porosity to enhance mass transfer. A series of cerium-modified catalysts were further synthesized by ion-exchange method to optimize structural and surface properties. The highest conversion of Ce-modified catalyst reached 95.78%, which may be ascribed to the abundant acid active sites, hierarchical porosity and metal functions effectively improving catalytic performance.