Ammonia (NH3) is essential for modern agriculture and industry and is a potential energy carrier. NH3 is traditionally synthesized by the Haber–Bosch process at high temperature and pressure. The high-energy input of this process has motivated research into electrochemical NH3 synthesis via nitrogen (N2)–water reactions under ambient conditions. However, the future of this low-cost process is compromised by the low yield rate and poor selectivity, ascribed to the inert N≡N bond and ultralow solubility of N2. Obtaining NH3 directly from non-N2 sources could circumvent these challenges. Here we report the eight-electron direct electroreduction of nitrate to NH3 catalysed by copper-incorporated crystalline 3,4,9,10-perylenetetracarboxylic dianhydride. The catalyst exhibits an NH3 production rate of 436 ± 85 μg h−1 cm−2 and a maximum Faradaic efficiency of 85.9% at −0.4 V versus a reversible hydrogen electrode. This notable performance is achieved by the catalyst regulating the transfer of protons and/or electrons to the copper centres and suppressing hydrogen production.
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G.-F.C. thanks the Alexander von Humboldt Foundation for a postdoctoral fellowship. This work was financially supported by the National Natural Science Foundation of China (21536005, 51621001 and 21776099), the Post-Doctoral Innovative Talents Project (BX20190119) and National Key R&D Program (2016YFA0202601). A portion of this work was conducted at Argonne National Laboratory. Argonne National Laboratory is operated for the DOE Office of Science by UChicago Argonne, LLC, under contract no. DE-AC02-06CH11357. Use of the Advanced Photon Source (beamline 9BM), Office of Science user facilities, was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract no. DE-AC02-06CH11357.
The authors declare no competing interests.
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Chen, G., Yuan, Y., Jiang, H. et al. Electrochemical reduction of nitrate to ammonia via direct eight-electron transfer using a copper–molecular solid catalyst. Nat Energy 5, 605–613 (2020). https://doi.org/10.1038/s41560-020-0654-1
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