Stabilizing F-Al-O active center via confinement of Al2O3 in SiC framework for conversion of 1,1-difluoroethane greenhouse gas

Abstract

Al₂O₃ exhibits high activity for the resource utilization of potent greenhouse gases, hydrofluorocarbons via dehydrofluorination or F/Cl exchange. However, it experiences completely fluorination under corrosive HF environment, leading to thorough fluorination of F-Al-O active site into F-Al-F, accompanied with serious carbon deposition. In this work, we successfully confined Al₂O₃ in SiC (Al₂O₃@SiC) via treating Al₂O₃/SiC under high temperatures (>800 °C). The results showed that different with simple loaded Al₂O₃(Al₂O₃/SiC), during high temperature treatment, reaction between Al₂O₃ and SiC occurred, leading to the confinement effect. Then, contributed by the interaction, desired F-Al-O species could be stabilized on the surface of SiC. While for Al₂O₃/SiC, it thoroughly turned into AlF₃ under identical reactive conditions, leading to inferior stability during CH₃CHF₂ dehydrofluorination. Furthermore, the reaction rate of 5 %Al₂O₃@SiC is nearly up to 4 folds higher than that of traditional AlF₃. Facilitated by the suitable Lewis acid intensity, less carbon deposition formed on Al₂O₃@SiC. Thus, constructing strong interaction between F-Al-O and stable SiC provides a potential strategy to stabilize unstable active centers.