Rational design of structured Co₃O₄@silicalite-1/SiC foam catalyst for microwave-assisted highly efficient conversion of bio-isopropanol to green propylene

Globally, there is an increasing demand for propylene. Propylene can be produced through the dehydration of bio-isopropanol, which is derived from the fermentation of renewable feedstock. In this study, to enhance the efficiency of the bio-isopropanol-to-propylene (BITP) process, a microwave-sensitive Co₃O₄@S1/SiC foam catalyst was designed. The performance of the foam catalyst was evaluated across a range of temperatures (50–250 °C) and different heating modes. Investigations revealed that microwave irradiation resulted in a selective formation of propylene of 98.8 %, markedly surpassing the 72.7 % yield achieved with Co₃O₄@S1/SiC pellets. The exceptional efficiency of the Co₃O₄@S1/SiC foam in the bio-isopropanol-to-propylene process is predominantly attributable to the enhanced mass and heat transfer facilitated by the well-structured, microwave-sensitive foam SiC. Under microwave irradiation at lower temperatures, this foam catalyst exhibits significantly enhanced efficiency, achieving a 90 % conversion rate at 121 °C, in contrast to the 184 °C required by conventional heating methods to attain a similar rate. Moreover, the synergistic effect between Co₃O₄ and the second support S1 is crucial, enhancing not only the microwave absorption capacity but also the efficiency of the bio-isopropanol dehydration process.