Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic Effects

Abstract Electrochemical conversion of waste nitrate (NO3−) to ammonia (NH3) for environmental applications, such as carbon‐neutral energy sources and hydrogen carriers, is a promising alternative to the energy‐intensive Haber–Bosch process. However, increasing the energy efficiency is limited by th...

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Main Authors: Jungwon Suh, Hyeonuk Choi, Yujin Kong, Jihun Oh
Format: Article
Language:English
Published: Wiley 2024-11-01
Series:Advanced Science
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Online Access:https://doi.org/10.1002/advs.202407250
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author Jungwon Suh
Hyeonuk Choi
Yujin Kong
Jihun Oh
author_facet Jungwon Suh
Hyeonuk Choi
Yujin Kong
Jihun Oh
author_sort Jungwon Suh
collection DOAJ
description Abstract Electrochemical conversion of waste nitrate (NO3−) to ammonia (NH3) for environmental applications, such as carbon‐neutral energy sources and hydrogen carriers, is a promising alternative to the energy‐intensive Haber–Bosch process. However, increasing the energy efficiency is limited by the high overpotential and selectivity. Herein, a Co─Cu mixed single‐atom/cluster catalyst (Co─Cu SCC) is demonstrated—with well‐dispersed Co and Cu active sites anchored on a carbon support—that delivers high NH3 Faradaic efficiency of 91.2% at low potential (–0.3 V vs. RHE) due to synergism between the heterogenous active sites. Electrochemical analyses reveal that Cu in Co─Cu SCC preferentially catalyzes the NO3−‐to‐NO2− pathway, whereupon Co catalyzes the NO2−‐to‐NH3 pathway. This tandem electroreduction bypasses the rate‐determining steps (RDSs) for Co and Cu to lower the reaction energy barrier and surpass scaling relationship limitations. The electrocatalytic performance is amplified by the subnanoscale catalyst to increase the partial current density of NH3 by 2.3 and 5.4 times compared to those of individual Co, Cu single‐atom/cluster catalysts (Co SCC, Cu SCC), respectively. This Co─Cu SCC is operated stably for 32 h in a long‐term bipolar membrane (BPM)‐based membrane electrode assembly (MEA) system for high‐concentration NH3 synthesis to produce over 1 m NH3 for conversion into high‐purity NH4Cl at 2.1 g day−1.
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spelling doaj-art-3c969723fccf48c6906ebec834c0fbd62025-08-20T02:15:32ZengWileyAdvanced Science2198-38442024-11-011142n/an/a10.1002/advs.202407250Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic EffectsJungwon Suh0Hyeonuk Choi1Yujin Kong2Jihun Oh3Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) 291 Daehak‐ro, Yuseong‐gu Daejeon 34141 Republic of KoreaDepartment of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) 291 Daehak‐ro, Yuseong‐gu Daejeon 34141 Republic of KoreaDepartment of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) 291 Daehak‐ro, Yuseong‐gu Daejeon 34141 Republic of KoreaDepartment of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) 291 Daehak‐ro, Yuseong‐gu Daejeon 34141 Republic of KoreaAbstract Electrochemical conversion of waste nitrate (NO3−) to ammonia (NH3) for environmental applications, such as carbon‐neutral energy sources and hydrogen carriers, is a promising alternative to the energy‐intensive Haber–Bosch process. However, increasing the energy efficiency is limited by the high overpotential and selectivity. Herein, a Co─Cu mixed single‐atom/cluster catalyst (Co─Cu SCC) is demonstrated—with well‐dispersed Co and Cu active sites anchored on a carbon support—that delivers high NH3 Faradaic efficiency of 91.2% at low potential (–0.3 V vs. RHE) due to synergism between the heterogenous active sites. Electrochemical analyses reveal that Cu in Co─Cu SCC preferentially catalyzes the NO3−‐to‐NO2− pathway, whereupon Co catalyzes the NO2−‐to‐NH3 pathway. This tandem electroreduction bypasses the rate‐determining steps (RDSs) for Co and Cu to lower the reaction energy barrier and surpass scaling relationship limitations. The electrocatalytic performance is amplified by the subnanoscale catalyst to increase the partial current density of NH3 by 2.3 and 5.4 times compared to those of individual Co, Cu single‐atom/cluster catalysts (Co SCC, Cu SCC), respectively. This Co─Cu SCC is operated stably for 32 h in a long‐term bipolar membrane (BPM)‐based membrane electrode assembly (MEA) system for high‐concentration NH3 synthesis to produce over 1 m NH3 for conversion into high‐purity NH4Cl at 2.1 g day−1.https://doi.org/10.1002/advs.202407250ammonia synthesisdual‐atom catalystselectrochemical catalystsheterogeneous catalyststandem electroreduction
spellingShingle Jungwon Suh
Hyeonuk Choi
Yujin Kong
Jihun Oh
Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic Effects
Advanced Science
ammonia synthesis
dual‐atom catalysts
electrochemical catalysts
heterogeneous catalysts
tandem electroreduction
title Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic Effects
title_full Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic Effects
title_fullStr Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic Effects
title_full_unstemmed Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic Effects
title_short Tandem Electroreduction of Nitrate to Ammonia Using a Cobalt–Copper Mixed Single‐Atom/Cluster Catalyst with Synergistic Effects
title_sort tandem electroreduction of nitrate to ammonia using a cobalt copper mixed single atom cluster catalyst with synergistic effects
topic ammonia synthesis
dual‐atom catalysts
electrochemical catalysts
heterogeneous catalysts
tandem electroreduction
url https://doi.org/10.1002/advs.202407250
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AT jihunoh tandemelectroreductionofnitratetoammoniausingacobaltcoppermixedsingleatomclustercatalystwithsynergisticeffects