The Zr Modified γ-Al₂O₃ Catalysts for Stable Hydrolytic Decomposition of CF₄ at Low Temperature

Abstract

CF4, one of the Perfluorocompounds (PFCs), also known as a greenhouse gas with high global warming potential. In this study, Zr/γ-Al2O3 catalysts were developed for CF4 decomposition. The addition of Zr onto γ-Al2O3 achieves a high CF4 conversion efficiency of 85% at 650 °C and maintain its activity for more than 60 h, which is obviously higher than that of bare γ-Al2O3 (50%). The mechanism involved in CF4 decomposition over the Zr/γ-Al2O3 are clarified that the surface Lewis acidity sites are the main active center for CF4 directly adsorbing and decomposing. The results of NH3-TPD and FT-IR analyses suggest that the amount of Lewis acidity sites on catalyst surface increases significantly after the introduction of Zr, thereby enhancing the activity of catalyst for CF4 decomposition. The results of XPS analyses confirms the electrons transfer from Zr to Al, which contribute to the increase in Lewis acidity sites. The results of this work will help the development of more effective catalysts for CF4 decomposition.

Keywords

• CF₄
• perfluorocompounds
• catalytic decomposition
• Lewis acid site
• alumina
• zirconia