Vertex Strategy in Layered 2D MOFs: Simultaneous Improvement of Thermodynamics and Kinetics for Record C<sub>2</sub>H<sub>2</sub>/CO<sub>2</sub> Separation Performance
Xiaoqian Zhu, Ke Tian, Jingyi Zhou, Yifei Song, Qianqian Xu, Zhiguo Zhang, Zongbi Bao, Yiwen Yang, Qilong Ren, Qiwei Yang
Abstract
Developing adsorbents with multiple merits in capacity, selectivity, mass transfer, and stability toward C 2 H 2 /CO 2 separation is crucial and challenging for producing high-purity C 2 H 2 for advanced polymers and the electronic industry. Here, we demonstrate a vertex strategy to create adsorbents combining these merits through rationally designing the vertex groups of a wavy-shaped framework in layered 2D metal–organic frameworks (MOFs) to finely regulate the local conformation and stacking interactions, which creates the optimal inter- and intralayer space to realize simultaneous improvement of adsorption thermodynamics and kinetics. Two new hydrolytically stable MOFs, ZUL-330 and ZUL-430, were prepared, and diverse experiments and modeling on both adsorption equilibrium and diffusion were performed. Record separation selectivities coupled with extraordinary dynamic C 2 H 2 capacities were achieved for C 2 H 2 /CO 2 mixtures with different proportions (50/50 or 10/5, v/v), along with a small diffusion barrier and fast mass transfer. Consequently, polymer-grade (99.9%) and electronic-grade (99.99%) C 2 H 2 were obtained with excellent productivities of up to ∼6 mmol cm –3 .