Efficient and stable CF4 decomposition over θ-Al2O3 with extraordinary resistance to HF

CF4 is the most emitted perfluorocarbon (PFC) and possesses a great global warming potential (GWP) of 7390 with a lifetime of 50 000 years. Catalytic hydrolysis is a promising method for reducing CF4 emissions; however, the HF product can easily poison the catalyst, resulting in poor stability. In this study, a strategy for resisting HF corrosion by enhancing the order of aluminum-oxide polyhedron is originally demonstrated. HF corrosion experiments indicated that the Al2O3 catalysts with a higher order of aluminum-oxide polyhedron exhibited better resistance to HF corrosion (HF corrosion reaction rate k2, γ-Al2O3: 1.34 × 10−3, θ-Al2O3: 1.90 × 10−5, and α-Al2O3: 1.30 × 10−5). The obtained θ-Al2O3 achieved a lifetime of 100 h with 100% decomposition of CF4 at 750 °C, which is ∼20 times that of the γ-Al2O3 catalyst, and α-Al2O3 was inactive for CF4 decomposition. Theoretical calculations also demonstrated that θ-Al2O3 had lower adsorption and higher reaction barriers with HF than those of γ-Al2O3, proving the high stability of θ-Al2O3. This study provides a new inspiration for the development of efficient and stable CF4 decomposition catalysts.