Tuning the Integration Proximity between Na Promoter and FeMnO<sub><i>x</i></sub> Coupled with Rationally Modified HZSM-5 to Promote Selective CO<sub>2</sub> Hydrogenation to Aromatics
Guiyao Song, Minzhe Li, Lin Xu, Xiaopei Yang, Muhammad Asif Nawaz, Huimin Yuan, Zhixiang Zhang, Xianming Xu, Dianhua Liu
Abstract
Selective CO2 hydrogenation to aromatics has received widespread reputation, whereas high CO2 inertness and complex structure within aromatics inevitably depress the catalytic performance. Herein, we fabricated a bifunctional catalyst comprising active sodium-promoted FeMnOx and HZSM-5 for CO2 hydrogenation to aromatics with 64.24% selectivity at a single pass conversion of 44.49%. The appropriate proximity between Na and FeMnOx can endow CO2 hydrogenation with optimized performance, due to its regulation of both the electronic properties of iron species and the distribution of Fe3O4 and Fe5C2 on catalyst. Additionally, aromatics and BTX selectivity can be remarkably improved to 71.52% and 63.51% respectively on phosphorus modified HZSM-5, owing to the improved mesoporosity and partially passivated Brønsted acid sites. Significantly, we demonstrated a plausible mechanism during Fischer–Tropsch Synthesis that the increased iron carbide promotes lower olefins production, simultaneously, the generated lower olefins in turn contribute to the formation of iron carbide.