Tandem Nitrate-to-Ammonia Conversion on Atomically Precise Silver Nanocluster/MXene Electrocatalyst.

Electrocatalytic reduction of nitrate (NO 3 RR) to synthesize ammonia (NH 3 ) provides a competitive manner for carbon neutrality and decentralized NH 3 synthesis. Atomically precise nanoclusters, as an advantageous platform for investigating the NO 3 RR mechanisms and actual active sites, remain largely underexplored due to the poor stability. Herein, we report a (NH 4 ) 9 [Ag 9 (mba) 9 ] nanoclusters (Ag 9 NCs) loaded on Ti 3 C 2 MXene (Ag 9 /MXene) for highly efficient NO 3 RR performance towards ambient NH 3 synthesis with improved stability in neutral medium. The composite structure of MXene and Ag 9 NCs enables a tandem catalysis process for nitrate reduction, significantly increasing the selectivity and FE of NH 3 . Besides, compared with individual Ag 9 NCs, Ag 9 /MXene has better stability with the current density performed no decay after 108 hours of reaction. This work provides a strategy for improving the catalytic activity and stability of atomically precise metal NCs, expanding the mechanism research and application of metal NCs.