Performance and Lifespan Analysis of Modified Al₂O₃ Catalysts under Varying Oxygen Concentrations and Temperatures for the Degradation of 1,1,1,2-Tetrafluoroethane

Global warming and the Montreal Protocol necessitate efficient HFC refrigerant degradation. This study evaluates Al2O3 catalysts modified by phosphorus loading, high-temperature calcination, and fluorination. XRD, NH3-TPD, Raman spectroscopy, and lifespan experiments showed all catalysts remained in the γ-Al2O3 phase, initially achieving over 99.5% degradation. Significant differences in activity lifespan were observed: P-5-Al2O3 exhibited the highest final activity due to abundant Lewis acidic sites, while Al2O3-700 demonstrated superior retention, attributed to unique crystalline features, higher active site density, and efficient AlF3 phase formation. Activity model parameters (rAlF3,max, kr, SAl2O3,0/NAl2O3, and SAl2O3,0/ka) quantified deactivation dynamics and highlighted the impact of modification methods. Oxygen concentration enhanced degradation rates, CO2 selectivity, and reduced carbon deposition, while temperatures above 450 °C achieved near-complete degradation. Kinetic analysis revealed a reaction order of 1.434 and activation energy of 70.26 kJ/mol.