Guangjun Wu

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.

The catalyst H–Ni@Y, featuring coordinatively unsaturated Ni species confined at Site II of a Brønsted-acid-rich FAU zeolite, achieves an ethylene dimerization rate of 4.28 × 10 ⁵ h ⁻¹ for 1-butene with 83.6% selectivity in a fixed-bed reactor.

The development of adsorbents for ammonia capture and separation is a challenging task, with significant industrial relevance. We report herein, for the first time, open aluminophosphate frameworks for on-demand ammonia adsorption. Under ambient conditions, the AlPO-18 molecular sieve exhibits exceptional dynamic ammonia uptake of 3.36 mmol/g at an extremely low ammonia concentration of 200 ppm, showing great potential as a disposable adsorbent for trace ammonia capture. AlPO-11 molecular sieve manifests a desirable ammonia dynamic uptake of 5.73 mmol/g at high ammonia concentration of 50,000 ppm, with excellent recyclability upon regeneration under mild conditions. Aspen simulations demonstrate the advantage of the adsorptive separation process employing AlPO-11 adsorbent for ammonia recovery, with huge energy savings of 51% in comparison with the compression-based process currently employed in the ammonia synthesis industry. The underlying mechanism of ammonia adsorption and the nature of ammonia binding in aluminophosphate frameworks are fully elucidated by employing a combination of X-ray photoelectron spectroscopy, in situ Fourier transform infrared spectroscopy, quasi in situ magic angle spinning nuclear magnetic resonance, and density functional theory calculations. The coordination of ammonia on the framework aluminum sites in aluminophosphates is clearly disclosed. The development of low-cost and commercially available aluminophosphate molecular sieves may unlock their potential for on-demand ammonia capture and separation in various scenarios.

Building a sustainable energy system is currently a major challenge. In this review, we introduce catalysis of promising sustainable energy systems, aiming to draw attention to sustainable development in energy.

Self-pillared pentasil (SPP) zeolites have received considerable interest due to their distinctive intergrowth structure, while the precise process and mechanism for the formation of SPP zeolites remain obscure. Herein, SPP zeolites (ZSM-5) have been successfully synthesized by pre-aging an Al-rich gel without employing any organic templates or seeds for the first time. The as-synthesized SPP zeolites possess a notably high external surface area while the micropores for Ar adsorption are partially blocked by excess Na⁺, which can be fully recovered by Mg²⁺ or H⁺ exchange. The crystallization process is monitored and the impacts of synthesis parameters are investigated. The results show that self-pillaring originates from the partial lattice distortion at the intersections of nanosheets, offering a new insight into the self-pillaring process. Typically, with decreasing SiO₂/Al₂O₃ ratio, more crossovers could be observed in the crystals, hinting that self-pillaring predominately occurs at the (101) plane of twins in the ZSM-5 precursor due to Al-rich lattice distortion. Finally, in the catalytic cracking of n-heptane, H-SPP zeolites exhibit superior performance to commercial H-ZSM-5 zeolites due to their abundant Brønsted acid sites arising from a low framework SiO₂/Al₂O₃ ratio of ∼21 and the short diffusion path originating from the house-of-cards structure.