Landong Li

The rational design of metal‐acid bifunctional catalysts is critical for tandem catalysis. However, the precise control of intermediate formation and conversion remains challenging due to indiscriminate reactant access to both metal and acid centers. Herein, we utilize the steric hindrance of the sodalite (SOD) framework to exclude bulky benzene and cyclohexene from accessing the metal sites, confining intermediate cyclohexene formation and conversion exclusively to acidic domains and breaking the conventional competitive pathway of cyclohexene migration from metal to adjacent acid sites. Experimentally, Ru nanoparticles were confined within the SOD framework (Ru@SOD), and distal acid sites were introduced by mixing with HY zeolite. In‐depth studies reveal that coupled hydrogenation‐alkylation reactions over HY domains drive a hydrogen pump effect, which continuously draws active hydrogen spillover from encapsulated Ru sites to sustain efficient benzene hydroalkylation. Such isolated metal‐acid architecture redirects the pathway from a competitive hydrogenation/alkylation to an acid‐driven alkylation mediated by hydrogen spillover. At ∼40% benzene conversion, 75.6% cyclohexylbenzene (CHB) selectivity and a record‐high 47.3% CHB yield were achieved with the Ru@SOD + HY catalyst, significantly outperforming reference samples and other catalysts reported to date. This work provides a universal spatial isolation of metal‐acid sites to modulate intermediate evolution and optimize selectivity in complex tandem catalysis.

The rational design of metal‐acid bifunctional catalysts is critical for tandem catalysis. However, the precise control of intermediate formation and conversion remains challenging due to indiscriminate reactant access to both metal and acid centers. Herein, we utilize the steric hindrance of the sodalite (SOD) framework to exclude bulky benzene and cyclohexene from accessing the metal sites, confining intermediate cyclohexene formation and conversion exclusively to acidic domains and breaking the conventional competitive pathway of cyclohexene migration from metal to adjacent acid sites. Experimentally, Ru nanoparticles were confined within the SOD framework (Ru@SOD), and distal acid sites were introduced by mixing with HY zeolite. In‐depth studies reveal that coupled hydrogenation‐alkylation reactions over HY domains drive a hydrogen pump effect, which continuously draws active hydrogen spillover from encapsulated Ru sites to sustain efficient benzene hydroalkylation. Such isolated metal‐acid architecture redirects the pathway from a competitive hydrogenation/alkylation to an acid‐driven alkylation mediated by hydrogen spillover. At ∼40% benzene conversion, 75.6% cyclohexylbenzene (CHB) selectivity and a record‐high 47.3% CHB yield were achieved with the Ru@SOD + HY catalyst, significantly outperforming reference samples and other catalysts reported to date. This work provides a universal spatial isolation of metal‐acid sites to modulate intermediate evolution and optimize selectivity in complex tandem catalysis.

The direct deconstruction of polyolefins into olefins without external hydrogen source represents an ideal route for polyolefin upcycling, but it remains challenging due to the apparent trade-off between substrate conversion and product selectivity. We report herein layered MEL zeolite with confined Ru species synthesized through a ligand-assisted hydrothermal route, namely Ru@MEL, as an efficient catalyst for the quantitative upcycling of polyethylene to liquid olefins. The optimized Ru@MEL catalyst achieves >99% polyethylene conversion with 92% selectivity toward C₅-C₉ olefins at 270 °C within 4 h, surpassing all catalyst systems reported so far. Ru incorporation drives framework aluminum migration into the straight channels of MEL zeolite during crystallization, thereby promoting the spatial proximity of Ru species to Brønsted and Lewis acid sites toward efficient catalysis. Mechanism insights disclose a synergistic cycle involving key steps of Ru-mediated C-H activation, Brønsted acid-catalyzed β-scission, and Lewis acid-assisted hydrogen transfer. Ru@MEL catalyst exhibits high efficiency, good stability, and scalability in upcycling real-world plastic wastes, highlighting its potential for practical applications.