Synergistic effect of a manganese-based catalyst and its performance in catalytic cracking of PFPE

Abstract

Perfluoropolyether (PFPE) is a polymer with many excellent properties. However, PFPE can become waste lubricating oil after use under severe conditions, causing environmental hazards. In this study, we optimized the preparation conditions of manganese-based catalysts with different templates and then introduced a representative transition metal (Fe) and rare metal (Ce) to control their acid properties and oxygen vacancies for improving the cracking rate of PFPE. The results showed that the cracking rate of PFPE using the Fe/MnO₂ catalyst reached 73.2% at 350 °C. Additionally, the characterization results revealed that the introduction of Fe increased the content of Mn⁴⁺ and weakened the Mn–O bond strength, which led to the generation of more active oxygen species, thereby enhancing the ability to activate PFPE. Moreover, the Fe/MnO₂ catalyst possessed moderate acid properties to promote the adsorption of PFPE. Combined with the beneficial strategy of using Na₂CO₃ for fluoride fixation, this highly active manganese-based catalyst can convert PFPE into substances with low toxicity or even no toxicity, thereby reducing the environmental hazards.