A facile solvent-free synthesis strategy for Co-imbedded zeolite-based Fischer-Tropsch catalysts for direct gasoline production

A series of Co-imbedded zeolite-based catalysts were synthesized following a facile solvent-free grinding route. The catalytic performance for direct syngas conversion to gasoline range hydrocarbons was compared with their counterpart Co-impregnated zeolite-based catalysts. Successful transformation of solid raw materials to targeted zeolite was confirmed by XRD, SEM, STEM, and N₂ physisorption analysis. An in-depth study of acidic strength and acidic site distribution was conducted by NH₃-TPD and Py-IR spectroscopy. Acidic strength showed a pivotal role in defining product range. Co@S1, with the weakest acidic strength of silicalite-1 among three types of zeolites, evaded over-cracking of product and exhibited the highest gasoline and isoparaffin selectivity (≈70% and 30.7%, respectively). Moreover, the solvent-free raw material grinding route for zeolite synthesis accompanies several advantages like the elimination of production of wastewater, high product yield within confined crystallization space, and elimination of safety concerns regarding high pressure due to the absence of the solvent. Facileness and easiness of the solvent-free synthesis route together with promising catalytic performance strongly support its application on the industrial scale.