Facile construction of Cu(I)Y zeolite via olefin-mediated reduction for separation of olefin/paraffin

Ethylene (C₂H₄) is a central resource for various chemical products, serving as a foundational building block for items like polyethylene and ethylene glycol. However, the efficient separation of C₂H₄ from ethane (C₂H₆) poses challenges due to their similar molecular sizes and boiling points. In this context, Cu(I)-bearing adsorbents show significant potential for C₂H₄/C₂H₆ separation, as Cu(I) selectively interacts with C₂H₄ through π-complexation. Nonetheless, the preparation of these adsorbents requires harsh conditions (usually ≥700 °C for over 12 h) to convert Cu(II) species to Cu(I) sites via the traditional self-reduction method, leading to significant energy consumption. This study introduces a mild olefin-mediated reduction method to achieve controlled construction of Cu(I) sites in zeolite Y. Propylene, as a mild reductant, significantly lowers the reduction energy barrier from 510 kJ/mol (under traditional self-reduction) to 332 kJ/mol, allowing for Cu(I) reduction at temperatures below 130 °C for just 2 h. Moreover, the yield of Cu(I) achieved through the olefin-mediated reduction (85.1 %) surpasses that of the high-temperature self-reduction method (≤60 %). Thanks to the abundant Cu(I) sites, the resulting Cu(I)Y-R exhibits an exceptional C₂H₄ uptake and impressive C₂H₄/C₂H₆ selectivity, achieving values of 4.37 mmol/g and 98.31, respectively. This performance surpasses that of various reported adsorbents, including zeolites, mesoporous carbons, and metal–organic frameworks. After five cycles, Cu(I)Y-R maintains its high adsorption capacity, indicating remarkable cyclic stability. This material's remarkable C₂H₄ uptake and selectivity make it a viable option for effective C₂H₄/C₂H₆ separation in industrial settings.