Constructing Well-Defined and Robust Th-MOF-Supported Single-Site Copper for Production and Storage of Ammonia from Electroreduction of Nitrate

A combined technique of production and storage of ammonia (NH3) from electroreduction of nitrate (NO3) through one material is highly desirable but remains a huge challenge. Herein, we proposed a proof-of-concept strategy for combined NH3 production and storage from electroreduction of NO3- through elaborately designing a single-site Cu-II-bipyridine-based thorium metal-organic framework (CupTh-BPYDC). Notice- ably, the single Cu-II site, anchored by a solid-liquid postsynthetic metalation within Th-BPYDC, shows a novel square coordination structure, as determined by the single-crystal X-ray diffraction. This strongly implies its enormous potential as an open metal site and consequently enables excellent performance in electroreduction of NO3- for NH3 production, giving 92.5% Faradaic efficiency and 225.3 mu mol h(-1) cm(-2) yield. Impressively, we can further use Cu@Th-BPYDC material to effectively capture the previously produced NH3 from electroreduction of NO3-, affording an uptake up to 20.55 mmol g(-1) at 298 K at 1 bar. The results in this work will outline a new direction toward the combined technique for advanced electrocatalysis such as gas production plus storage/or separation.

Automated summary

The study proposed a novel method for the production and storage of ammonia through the electroreduction of nitrate using a specially designed metal-organic framework. The experimental results show that the framework has great potential and can achieve high yields. This technique opens up a new direction for advanced electrocatalysis.