Catalytic dehydrofluorination of 1,1,1,3,3-pentafluoropropane to 1,3,3,3-tetrafluoropropene over fluorinated NiO/Cr2O3 catalysts

Catalytic dehydrofluorination of 1,1,1,3,3-pentafluoropropane to 1,3,3,3-tetrafluoropropene was performed on a series of fluorinated NiO/Cr 2 O 3 catalysts. The NiO/Cr 2 O 3 catalysts were more active than the Cr 2 O 3 because the new acid sites provided by NiF 2 had higher turnover frequencies (9.43   ×   10 −3   −   12.08   ×   10 −3   s −1 ) than those on the Cr 2 O 3 (4.55   ×   10 −3   s −1 ). Also, the NiO/Cr 2 O 3 was more stable than the Cr 2 O 3 due to its lower density of surface acid sites, which alleviated the coke deposition on the catalyst as evidenced by the Raman spectroscopic results. The kinetic results revealed that the15NiO/Cr 2 O 3 had much lower activation energy (63.6   ±   4.5   kJ   mol −1 ) than the Cr 2 O 3 (127.6   ±   3.8   kJ   mol −1 ). Accordingly, different reaction pathways on the two catalysts were proposed, which involved the cleavage of the C F and C H bonds on the surface acid and base sites, respectively.