A multifunctional anionic metal-organic framework for high proton conductivity and photoreduction of CO 2 induced by cation exchange.

Metal-organic frameworks (MOFs) provide an ideal platform for loading various guests owing to their available space, and can be developed as a class of multifunctional materials. Herein, we cover the design and synthesis of two kinds of exchanged frameworks with multifunctional applications based on H ₃ ImDC and In(NO ₃ ) ₃ ·2H ₂ O through guest exchange inside the framework. The guest ammonium ion (NH ₄ ⁺ ) and [Ru(2,2'-bipyridine) ₃ ] ²⁺ (Rubpy) are selected to exchange the dimethylammonium cation (Me ₂ NH ₂ ⁺ ) encapsulated within In-MOF , giving birth to two kinds of new MOFs, named NH ₄ ⁺ @In-MOF and Rubpy@In-MOF respectively. The proton conduction of NH ₄ ⁺ @In-MOF and the CO ₂ photoreduction of Rubpy@In-MOF are investigated. Under different test conditions, the proton conductive behaviors of NH ₄ ⁺ @In-MOF are evaluated and the best proton conductive value can reach up to 9.81 × 10 ^-3 S cm ^-1 . Compared to the original In-MOF , Rubpy@In-MOF exhibits a significantly enhanced CO ₂ photoreduction performance under a pure CO ₂ atmosphere. Furthermore, its photocatalytic activity is retained even under a 10% CO ₂ gas atmosphere, displaying a synergistic effect between Rubpy and In-MOF24 within Rubpy@In-MOF .