Enhancing the Conversion Efficiency of Polyethylene to Methane through Codoping of Mn Atoms into Ru Centers and CeO2 Supports

Abstract

Chemical conversion has emerged as an effective approach for disposing waste plastics; however, the product diversity in traditional methods leads to pressing challenges in product separation and purification. As a pioneering advancement, the comprehensive transformation of waste plastics into CH₄ presents an attractive prospect: directly yielding high-purity products. Significantly, CH₄ is an important hydrogen carrier and an industrial feedstock. However, there is still much room for enhancing the overall efficiency. Herein, we show a new strategy to construct a high-efficiency and robust polyethylene (PE) upgrading catalyst by codoping Mn heteroatoms into both RuO₂ and CeO₂. We found that these Mn heteroatoms effectively bolster the stability of Ru^δ+ species under high-temperature reduction conditions. The harmonious coexistence of Ru⁰ and Ru^δ+ significantly refines the reaction pathway by enhancing the adsorption of the alkane intermediates. Consequently, we achieved an impressive PE conversion rate exceeding >99% with nearly 99% toward CH₄ at a moderate temperature of 250 °C within 8 h. Our discovery not only opens a new window for catalyst upgrading but also presents exciting opportunities for the in-depth conversion of waste plastics into complex, high-purity fine chemicals through methane-mediated catalysis.