Improving the Selectivity and Stability of Supported Cobalt Catalysts via Static Bi‐Doping and Dynamic Trace CO2 Co‐feeding during Propane Dehydrogenation

Abstract

Simultaneously enhancing selectivity and stability on supported propane dehydrogenation (PDH) catalysts remains a formidable challenge. Here, we report a combined static and dynamic strategy to address these issues synergistically. Firstly, we demonstrate a feasible sol‐gel method for preparing atomically‐dispersed Bi‐decorated metal nanoparticle catalysts (MBi/Al2O3, M= Fe, Co, Ni, and Zn). In PDH testing, the total selectivity of by‐products (CH4 and C2H6) significantly decreases to 4% for CoBi catalysts due to the static Bi‐doping, compared with 16% for Co‐supported catalysts. Secondly, to enhance catalytic stability, we introduce a dynamic trace CO2 co‐feeding route. 10CoBi/Al2O3 catalysts exhibit superior durability against coke formation for 330 hours in PDH under a 40% C3H8 atmosphere followed by pure C3H8 conditions at 600 °C while maintaining propylene selectivity at 96%. Notably, introducing trace CO2 leads to a remarkable 6‐fold decrease in the deactivation rate constant (kd). Multiple characterizations and density functional theory calculations reveal that charge transfer from atomically‐distributed Bi to Co nanoparticles benefits lowering the energy of C3H6 adsorption thereby suppressing by‐products. Furthermore, the dynamic co‐feeding of trace CO2 facilitates coke removal, suppressing catalyst deactivation. The static Bi‐doping and dynamic trace CO2 co‐feeding strategy contributes simultaneously to increased selectivity and stability on supported PDH catalysts.