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

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.