Cobalt-based metal organic framework as precursor to achieve superior catalytic activity for aerobic epoxidation of styrene

Novel nitrogen-cobalt catalysts have been successfully synthesized via one-step pyrolysis of cobalt-based metal organic framework (ZIF-67) at different temperatures under an inert atmosphere. The influence of the carbonization temperature on the porous structure of the nitrogen-cobalt catalysts is comprehensively investigated through XRD, XPS and N-2 adsorption techniques. Furthermore, the catalytic performance is investigated for epoxidation of styrene using air as the terminal oxidant. The prepared catalysts exhibit excellent styrene conversion (76.2-91.3%) with better epoxide selectivity (81.3-84.8%) in comparison with neat ZIF-67 (39.3%, 79.4%). Advantageously, the magnetically recoverable catalysts could be efficiently reused for 5 times without noticeable deterioration in activity and selectivity. This work provides an elegant approach for the development of cost-effective and practical catalysts for oxidation reactions.