Plastics waste has become a major environmental threat, with polyethylene being one of the most produced and hardest to recycle plastics. Hydrogenolysis is potentially the most viable catalytic technology for recycling. Ruthenium (Ru) is one of the most active hydrogenolysis catalysts but yields too much methane. Here we introduce ruthenium supported on tungstated zirconia (Ru-WZr) for hydrogenolysis of low-density polyethylene (LDPE). We show that the Ru-WZr catalysts suppress methane formation and produce a product distribution in the diesel and wax/lubricant base-oil range unattainable by Ru-Zr and other Ru-supported catalysts. Importantly, the enhanced performance is showcased for real-world, single-use LDPE consumables. Reactivity studies combined with characterization and density functional theory calculations reveal that highly dispersed (WO_x)_n clusters store H as surface hydroxyls by spillover. We correlate this hydrogen storage mechanism with hydrogenation and desorption of long alkyl intermediates that would otherwise undergo further C–C scission to produce methane.

中文翻译：

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钨酸盐氧化锆上在温和条件下在钌上氢解聚乙烯

塑料废物已成为主要的环境威胁，聚乙烯是产量最多、最难回收的塑料之一。氢解可能是最可行的回收催化技术。钌 (Ru) 是最活跃的氢解催化剂之一，但会产生过多的甲烷。在这里，我们介绍了负载在钨酸氧化锆 (Ru-WZr) 上的钌，用于低密度聚乙烯 (LDPE) 的氢解。我们表明，Ru-WZr 催化剂抑制了甲烷的形成，并在柴油和蜡/润滑剂基础油范围内产生了 Ru-Zr 和其他 Ru 负载催化剂无法达到的产品分布。重要的是，增强的性能体现在真实世界的一次性 LDPE 耗材上。反应性研究结合表征和密度泛函理论计算表明，高度分散的 (WO_x ) _n簇通过溢出将 H 存储为表面羟基。我们将这种储氢机制与长烷基中间体的氢化和解吸相关联，否则这些中间体将经历进一步的 C-C 断裂以产生甲烷。