Zr-Modulated N Doping for Enhancing the Performance in the Direct Synthesis of Ethylene Carbonate from Ethylene Glycol and CO2

Acidic and basic sites of catalysts are essential tools in CO2 capture and activation. This work fabricated Zr, N-ZnO/ZnAl-LDH-IL composites in ionic liquid and methanol systems and was used to catalyze the synthesis of ethylene carbonate from ethylene glycol and CO2. The prepared composites have a high specific surface area of 205.542 m2 g-1. The Zr, N-ZnO/ZnAl-LDH-IL composites has a 4.16 times increase in the strong basic sites compared to N-ZnO/ZnAl-LDH-IL, mainly attributed to the fact that Zr-doped effectively induced changes in the reactive groups on the catalyst surface, increasing the percentage of pyridinic-N groups from 5.48% to 22.25%, inducing more C-atoms adjacent to pyridinic-N to exhibit strongly basic sites favoured the activation of CO2 and ethylene glycol. The experimental results show that the Zr, N-ZnO/ZnAl-LDH-IL composites have the best catalytic performance without adding any dehydrating agent at about 4.76 mmolEC gCat.-1 h-1. In addition to elucidating the possible catalytic pathways and reaction mechanisms of the composites for ethylene glycol and CO2 catalysis, we have also investigated the doping of La, Fe, Ce and Cu. Current work also indicates that controlling the acid-base centers on the surface of materials by ionic liquids and methanol solvents is an effective strategy.