Abstract
The integration of CO(2) into the dehydrogenation of propane (PDH) holds significant promise for both propylene production and greenhouse gas utilization. However, a pivotal challenge lies in mitigating the undesirable dry reforming of propane (DRP), which diminishes propylene selectivity compared to direct PDH processes. Herein, we describe a coupled process that integrates PDH with reverse water gas shift (RWGS) using a tandem catalytic system. The PtSn/Al(2)O(3) analogue performs the dehydrogenation reaction, while an adjacent defective CeO(x)/Al(2)O(3) at nanoscale acts as the hydrogenation sites for CO(2). Catalysis and kinetic studies demonstrate the in-situ removal of hydrogen from PtSn/Al(2)O(3) to adjacent CeO(x)/Al(2)O(3), facilitated by CO(2), shifts the quasi-equilibrium of PDH towards propylene production, while suppressing the competitive DRP side reaction. This hydrogen spillover-mediated coupling mechanism enables superior propylene selectivity of ~98.8%, along with high CO(2) (~43.9%) and propane conversion (~44.2%) at 550 °C, outperforming direct PDH (~40.6%). Analysis of CO(2) footprint indicates the PDH-RWGS tandem process has the potential for carbon utilization to mitigate detrimental CO(2) emissions.