Bioinspired Skeleton‐and‐Pore Regulation of Covalent Organic Frameworks for High‐Capacity and Ultrarapid Palladium Recovery
Yimin Cai, Qing Li, Dingguo Xu, Xiaowei Li, Ning Liu, Feng Wen, Lihua Yuan
Abstract
Abstract Selective palladium (Pd) recovery with high capacity and fast kinetics constitutes a significant but challenging task for nuclear waste treatment and compensating for noble metal scarcity. Herein, a bioinspired skeleton‐and‐pore regulation strategy is reported to construct intestinal villi‐like 1D artificial nanochannels in covalent organic frameworks (COFs) with record‐breaking Pd(II) capacity and kinetics at high acidity. The COFs feature both in situ‐generated hydrogen‐bonded hydrazone coordination sites on the skeleton and de novo constructed 2‐triazole‐pyridine (PyTri) chains as Pd(II) ion carriers protruding into the pore. Regulating the pore structures enables manipulation of stacking modes and hydrophilicity of COF, resulting in 2.3 times higher Pd(II) capacity (556 mg g −1 ) and 20 times faster kinetics (3 min for equilibrium) than a control COF without PyTri chains, representing two new records among all state‐of‐the‐art materials, along with ultra‐high selectivity, outstanding structural robustness, and extraordinary reusability. This work opens up a new avenue for developing advanced materials toward noble metal recovery.