Efficient Electrocatalytic Nitrate Reduction to Ammonia Based on DNA-Templated Copper Nanoclusters.

In alkaline solutions, the electrocatalytic conversion of nitrates to ammonia (NH) (NORR) is hindered by the sluggish hydrogenation step due to the lack of protons on the electrode surface, making it a grand challenge to synthesize NH at a high rate and selectivity. Herein, single-stranded deoxyribonucleic acid (ssDNA)-templated copper nanoclusters (CuNCs) were synthesized for the electrocatalytic production of NH. Because ssDNA was involved in the optimization of the interfacial water distribution and H-bond network connectivity, the water-electrolysis-induced proton generation was enhanced on the electrode surface, which facilitated the NORR kinetics. The activation energy () and in situ spectroscopy studies adequately demonstrated that the NORR was exothermic until NH desorption, indicating that, in alkaline media, the NORR catalyzed by ssDNA-templated CuNCs followed the same reaction path as the NORR in acidic media. Electrocatalytic tests further verified the efficiency of ssDNA-templated CuNCs, which achieved a high NH yield rate of 2.62 mg h cm and a Faraday efficiency of 96.8% at -0.6 V vs reversible hydrogen electrode. The results of this study lay the foundation for engineering catalyst surface ligands for the electrocatalytic NORR.