posted on 2024-01-31, 12:04authored byYiwei Sun, Xiaoli Wei, Wei Zhang, Zhen Wang, Jianhai Jiang, Fangcao Liu, Bing Liu, Wenfeng Han
Conversion of potent greenhouse gases, hydrofluorocarbons
(HFCs),
to value-added hydrofluoroolefins (HFOs) is of great importance. AlF3 catalysts play a major role in this process. Formation and
maintenance under coordinated Al are the key to prepare efficient
catalysts. Herein, carbon interacted AlF3 nanoclusters
catalyst (AlF3–SAPO-5) was effectively achieved
with SAPO-5 molecular sieves as precursors via pyrolysis followed
by in situ fluorination. This process results in a strong interaction
between the carbonaceous material and active aluminum (Al) species.
The results show that AlF3–SAPO-5 possesses both
high activity and thermal stability. For 1,1-difluoroethane (HFC-152a)
dehydrofluorination, the conversion can reach up to 95% at a reaction
temperature of 350 °C. The reaction rate is almost 4 times higher
than that of AlF3 prepared by traditional pyrolysis (AlF3-py). It implies that the confinement effect contributes to
the formation of AlF3 nanoclusters with abundant 4- and
5-coordinated Al species stabilized by the F–Al–O–C
structure. In addition, the carbon-interacted AlF3 nanoclusters
exhibit superb sintering resistance. Given its fantastic activity
and thermal stability, the carbon-interacted AlF3 nanoclusters
show great potential for the catalytic dehydrofluorination of fluorinated
alkanes.