Confined aluminum fluoride layers derived from the in situ etching of Ti3AlC2 as the robust catalyst for dehydrofluorination reaction

Abstract Aluminum fluoride layers (AlFx) were prepared by the in situ etching of Ti3AlC2 with 1,1-difluoroethane at elevated temperatures. During etching, Ti layers were fluorinated to stable TiF3 interacting with C to confine the Al species and sublimable TiF4. Al layers were fluorinated to unsaturated AlFx with relatively weak Lewis acidity. Due to the sublimation of TiF4, more AlFx acting as the main active centers were exposed to the reactants, and the surface areas of the confined-AlFx were increased, which contributed to the enhanced activity of the catalyst. The evaluation of the dehydrofluorination reaction showed that confined-AlFx layers presented higher reaction rate than F-γ-Al2O3 and AlF3. Besides, it was unexpected that TiF3 also exhibited activity for the reaction, even though the activity was much lower than confined-AlFx. Finally, the experimental results were confirmed by DFT calculations.