Abstract: Globally, the efficient utilization of polymer wastes is one of the most important issues for current sustainable development topics. Herein, a green and efficient low-temperature combustion approach is proposed to deal with polymer wastes and recover heat energy, simultaneously alleviating the environment and energy crisis. Non-noble metal oxides (Al₂O₃, Fe₂O₃, NiO₂, ZrO₂, La₂O₃ and CeO₂) were prepared, characterized and screened to boost the low-temperature combustion of polyethylene waste at 300 ℃ in air. The mass change, heat release and CO formation were studied in details and employed to evaluate the combustion rate and efficiency. It was found that CeO₂ significantly enhanced the combustion rate and efficiency, which was respectively 2 and 7 times that of non-catalytic case. An interesting phenomenon was observed that the catalytic performance of CeO₂ in polyethylene low-temperature combustion was significantly improved by the 7-day storage in the room environment or water treatment. XPS analysis confirmed the co-existence of Ce³⁺ and Ce⁴⁺ in CeO₂, and the 7-day storage and water treatment promoted the amount of Ce³⁺, which facilitated the formation of the oxygen vacancies. That may be the reason why CeO₂ exhibited excellent catalytic performance in polyethylene low-temperature combustion.

Key words: Polymer wastes, Low-temperature combustion, Metal oxides, CeO₂

摘要： Globally, the efficient utilization of polymer wastes is one of the most important issues for current sustainable development topics. Herein, a green and efficient low-temperature combustion approach is proposed to deal with polymer wastes and recover heat energy, simultaneously alleviating the environment and energy crisis. Non-noble metal oxides (Al₂O₃, Fe₂O₃, NiO₂, ZrO₂, La₂O₃ and CeO₂) were prepared, characterized and screened to boost the low-temperature combustion of polyethylene waste at 300 ℃ in air. The mass change, heat release and CO formation were studied in details and employed to evaluate the combustion rate and efficiency. It was found that CeO₂ significantly enhanced the combustion rate and efficiency, which was respectively 2 and 7 times that of non-catalytic case. An interesting phenomenon was observed that the catalytic performance of CeO₂ in polyethylene low-temperature combustion was significantly improved by the 7-day storage in the room environment or water treatment. XPS analysis confirmed the co-existence of Ce³⁺ and Ce⁴⁺ in CeO₂, and the 7-day storage and water treatment promoted the amount of Ce³⁺, which facilitated the formation of the oxygen vacancies. That may be the reason why CeO₂ exhibited excellent catalytic performance in polyethylene low-temperature combustion.

关键词: Polymer wastes, Low-temperature combustion, Metal oxides, CeO₂