Cr₂O₃/ZrO₂ catalyst for low-temperature catalytic hydrolysis of CFC-12: Performance, mechanism and regeneration

A Cr₂O₃/ZrO₂ composite catalyst was synthesized via co-precipitation for low-temperature catalytic hydrolysis of CFC-12. The optimal preparation conditions (Cr/Zr molar ratio = 1.00∶1.00, calcination at 500 ℃) yielded a mesoporous material with a high specific surface area of 248.01 m²/g and balanced acid-base sites (total acid: 0.45 mmol/g, total base: 0.32 mmol/g). Under mild conditions (100 ℃), the catalyst achieved 99.84% hydrolysis efficiency of CFC-12 and maintained >70% activity after 24 h on stream. Characterization (XRD, N₂ physisorption, NH₃/CO₂-TPD) revealed that the high performance originates from the acid-base synergistic effect between highly dispersed Cr₂O₃ and tetragonal ZrO₂, which facilitates C–Cl bond cleavage and H₂O activation. The deactivated catalyst was efficiently regenerated by calcination at 200 ℃, restoring 99.03% of its initial activity. This work demonstrates the potential of Cr₂O₃/ZrO₂ as a stable, regenerable, and environmentally safe catalyst for freon abatement.