A Novel Ni/NiF ₂ ‐AlF ₃ Catalyst with Mild‐Strength Lewis Acid Sites for Dehydrofluorination of 1, 1, 1, 2‐Tetrafluoroethane to Synthesize Trifluoroethylene

Abstract

Abstract A novel Ni/NiF 2 ‐AlF 3 catalyst was prepared by impregnation and following vapor hydrofluorination, and it was used to dehydrofluorination of tetrafluoroethane to trifluoroethylene. BET, SEM, XRD, XPS, NH 3 ‐TPD and Py‐IR techniques were employed to characterize the Ni/NiF 2 ‐AlF 3 catalysts. Based on the NH 3 ‐TPD results, it was interestingly found that the strong acidic sites of Ni/NiF 2 ‐AlF 3 catalyst transformed into the mid‐strength acidic sites with the increase of Ni loading, attributing to the roles of Ni on the catalyst surface. Compared with the NiF 2 ‐AlF 3 catalyst, the added Ni particles can improve the catalyst activity and stability for dehydrofluorination of 1, 1, 1, 2‐tetrafluoroethane. The best performance was obtained at Al/Ni=2 over the Ni/NiF 2 ‐AlF 3 catalyst, with high trifluoroethylene selectivity(99%) and CF 3 CFH 2 conversion of 21.3%, after the reaction for 20 h on‐time stream at 500 °C, which showed the better application possibility as a heterogeneous dehydrofluorination catalyst. It was suggested that catalytic performance was related with the mid‐strength Lewis acidity on the catalyst surface. And the Ni/NiF 2 ‐AlF 3 catalyst (Al/Ni=2) possessed the good catalytic stability due to the mild‐strength Lewis acid sites.