Tailoring Zn-based zeolitic imidazolate frameworks via Ni substitution: a strategy for enhanced selective alcohol adsorption and separation.

A stable four-coordinated nickel node has been successfully incorporated into a Zn-based zeolitic imidazolate framework (ZIF-8) via a facile one-pot synthesis at room temperature. By tuning the Ni/Zn ratios, the resulting physicochemical properties have been verified. The incorporation of Ni has led to improved alcohol separation compared to the single metal structure. The Ni-substituted ZIF-8, denoted as ZnNi, demonstrates selective adsorption and separation of alcohol molecules based on size and molecular interaction, effectively capturing trace methanol from ethanol mixtures. The partial substitution of ZnN4 with Ni introduces additional Ni centers and enhanced microporosity, which are potentially the key to such performance. These findings provide valuable insights into the development of mixed-metal organic frameworks for separation applications.