Electrochemically nitrate remediation by single-atom catalysts: advances, mechanisms, and prospects

Abstract

Electrocatalytic nitrate reduction reaction (NITRR) is highly desirable for remediating nitrate (NO₃^-) pollution and producing ammonia (NH₃) under mild conditions. To date, great efforts have been made to fabricate selective, efficient, and stable electrocatalysts for NITRR. Among the numerous strategies, single-atom catalysts (SACs) have received extensive interest and investigations due to their cost-effective and maximum atomic utilization. However, the further development of SACs-based NITRR remains hindered by a poor understanding of their in-depth mechanisms. Consequently, this review summarizes the recent advances of SACs for the NITRR, including Cu-SACs, Fe-SACs, Zn-SACs, Co-SACs, and single-atom alloys. In addition, the characterization techniques for SACs and reaction pathways of NITRR are presented to give a robust understanding of SACs-based NITRR. Finally, we analyze the current challenges in fabricating SACs for NITRR, while the key factors for further improving NITRR performances are also examined.

Keywords

Single-atom catalysts / electrocatalytic nitrate reduction reaction / electronic structure / characterization techniques

References

[1] Suryanto BHR,Choi J.Nitrogen reduction to ammonia at high efficiency and rates based on a phosphonium proton shuttle.Science2021;372:1187-91

[2] Wang S,Pang H,Ye J.Nitrogen fixation reaction derived from nanostructured catalytic materials.Adv Funct Mater2018;28:1803309

[3] Chen Z,Zhuang S.Periphytic biofilms-mediated microbial interactions and their impact on the nitrogen cycle in rice paddies.Eco Environ Health2022;1:172-80 PMCID:PMC10702904

[4] Wang Y,Jia R,Zhang B.Unveiling the activity origin of a copper-based electrocatalyst for selective nitrate reduction to ammonia.Angew Chem Int Ed2020;59:5350-4

[5] Rosca V,de Groot MT.Nitrogen cycle electrocatalysis.Chem Rev2009;109:2209-44

[6] Penuelas J.Human-driven global nutrient imbalances increase risks to health.Eco Environ Health2023;2:246-51 PMCID:PMC10902514

[7] Duca M.Powering denitrification: the perspectives of electrocatalytic nitrate reduction.Energy Environ Sci2012;5:9726-42

[8] Du R,Peng Y,Wang S.Combined partial denitrification (PD)-Anammox: A method for high nitrate wastewater treatment.Environ Int2019;126:707-16

[9] Shen J,Han W,Li J.Biological denitrification of high-nitrate wastewater in a modified anoxic/oxic-membrane bioreactor (A/O-MBR).J Hazard Mater2009;172:595-600

[10] Zheng W,Yan Z.Self-Activated Ni Cathode for Electrocatalytic Nitrate Reduction to Ammonia: From Fundamentals to Scale-Up for Treatment of Industrial Wastewater.Environ Sci Technol2021;55:13231-43

[11] Zhang C,Deng R.Enabling logistics automation in nanofactory: cobalt phosphide embedded metal-organic frameworks for efficient electrocatalytic nitrate reduction to ammonia. Adv Mater 2024:e2313844

[12] Li J,Yang J.Efficient ammonia electrosynthesis from nitrate on strained ruthenium nanoclusters.J Am Chem Soc2020;142:7036-46

[13] Jia R,Wang C,Yu Y.Boosting selective nitrate electroreduction to ammonium by constructing oxygen vacancies in TiO₂.ACS Catal2020;10:3533-40

[14] Gao Z,Tao Y,Zhang L.Constructing well-defined and robust Th-MOF-supported single-site copper for production and storage of ammonia from electroreduction of nitrate.ACS Cent Sci2021;7:1066-72 PMCID:PMC8228586

[15] Chen G,Jiang H.Electrochemical reduction of nitrate to ammonia via direct eight-electron transfer using a copper-molecular solid catalyst.Nat Energy2020;5:605-13

[16] Sun WJ,Li LX.Built-in electric field triggered interfacial accumulation effect for efficient nitrate removal at ultra-low concentration and electroreduction to ammonia.Angew Chem Int Ed2021;60:22933-9

[17] Carvalho OQ,Nguyen HKK.Role of electronic structure on nitrate reduction to ammonium: a periodic journey.J Am Chem Soc2022;144:14809-18

[18] Fan X,Zhang L.Enhanced electrocatalytic nitrate reduction to ammonia using plasma-induced oxygen vacancies in CoTiO_3-x nanofiber.Carbon Neutral2022;1:6-13

[19] Chen Y,Chen C,Wang D.Single-atom catalysts: synthetic strategies and electrochemical applications.Joule2018;2:1242-64

[20] Ding S,Lyu Z.Wearable microgrids empowered by single-atom materials.Innova Mater2023;2:100023

[21] Chakraborty R,Pradhan M.Recent advancement of biomass-derived porous carbon based materials for energy and environmental remediation applications.J Mater Chem A2022;10:6965-7005

[22] Wang Y,He Y.Advanced electrocatalysts with single-metal-atom active sites.Chem Rev2020;120:12217-314

[23] Zhao J,Barber J,Meng J.An overview of Cu-based heterogeneous electrocatalysts for CO₂ reduction.J Mater Chem A2020;8:4700-34

[24] Wei Y,Yan W.Recent processing of interaction mechanisms of single metallic atom/clusters in energy electrocatalysis.Energy Mater2023;3:300033

[25] Gong X,Han C,Mei X.Heterogeneous single-atom catalysts for energy process: recent progress, applications and challenges.Energy Mater2023;3:300016

[26] Cheng XF,Ji HQ.Coordination symmetry breaking of single-atom catalysts for robust and efficient nitrate electroreduction to ammonia.Adv Mater2022;34:e2205767

[27] Zhu C,Feng S,Lin Y.Single-atom catalysts for electrochemical water splitting.ACS Energy Lett2018;3:1713-21

[28] Shang W,Cai X.Insights into atomically dispersed reactive centers on g-C₃N₄ photocatalysts for water splitting.Adv Powder Mater2023;2:100094

[29] Jiang F,Pan Y.Design principles of single-atom catalysts for oxygen evolution reaction: from targeted structures to active sites.Adv Mater2024;36:e2306309

[30] Zhang J,Hong Y.Carbon-based single-atom catalysts in advanced oxidation reactions for water remediation: from materials to reaction pathways.Eco Environ Health2023;2:47-60 PMCID:PMC10702890

[31] Wan C,Huang Y.Molecular design of single-atom catalysts for oxygen reduction reaction.Adv Energy Mater2020;10:1903815

[32] Li Z,Ju Q.Spin engineering of single-site metal catalysts.Innovation2022;3:100268 PMCID:PMC9249949

[33] Han J,Sun C.Recent advances in single-atom electrocatalysts for oxygen reduction reaction.Research2020;2020:9512763 PMCID:PMC7443255

[34] Lu B,Nichols F.Oxygen reduction reaction catalyzed by carbon-supported platinum few-atom clusters: significant enhancement by doping of atomic cobalt.Research2020;2020:9167829 PMCID:PMC7877387

[35] Shao Y,Zhou J.Single-atom catalysts and dual-atom catalysts for CO₂ electroreduction: competition or cooperation?.Small2023;19:e2303446

[36] Tang T,Guan J.Achievements and challenges of copper-based single-atom catalysts for the reduction of carbon dioxide to C2+ products.Exploration2023;3:20230011 PMCID:PMC10582606

[37] Li M,Luo W,Chen J.Heterogeneous single-atom catalysts for electrochemical CO₂ reduction reaction.Adv Mater2020;32:e2001848

[38] Li X,Zhan X.Strategies for enhancing electrochemical CO₂ reduction to multi-carbon fuels on copper.Innov Mater2023;1:100014

[39] Li J,Quan F.Accelerated dinitrogen electroreduction to ammonia via interfacial polarization triggered by single-atom protrusions.Chem2020;6:885-901

[40] Wei X,Zhu X.Dynamic reconstitution between copper single atoms and clusters for electrocatalytic urea synthesis.Adv Mater2023;35:e2300020

[41] Chen H,Sheng L.Copper single-atom catalyst as a high-performance electrocatalyst for nitrate-ammonium conversion.J Hazard Mater2022;434:128892

[42] Wang L,Li Y.Single-atom catalysis for carbon neutrality.Carbon Energy2022;4:1021-79

[43] Wang Z,Wang M.In situ construction of metal-organic frameworks as smart channels for the effective electrocatalytic reduction of nitrate at ultralow concentrations to ammonia.ACS Catal2023;13:9125-35

[44] Hu T,Wang M,Guo C.Theoretical insights into superior nitrate reduction to ammonia performance of copper catalysts.ACS Catal2021;11:14417-27

[45] Zhao X,He Y.Two-dimensional BCN matrix inlaid with single-atom-Cu driven electrochemical nitrate reduction reaction to achieve sustainable industrial-grade production of ammonia.Appl Mater Today2021;25:101206

[46] Zhao X,Zhang H.Atomic-dispersed copper simultaneously achieve high-efficiency removal and high-value-added conversion to ammonia of nitrate in sewage.J Hazard Mater2022;424:127319

[47] Zhu T,Liao P.Single-atom Cu catalysts for enhanced electrocatalytic nitrate reduction with significant alleviation of nitrite production.Small2020;16:e2004526

[48] Zhao X,Dong F.Boosting the selectivity and efficiency of nitrate reduction to ammonia with a single-atom Cu electrocatalyst.Chem Eng J2023;466:143314

[49] Xue Y,Ma Q.Electrocatalytic hydrogenation boosts reduction of nitrate to ammonia over single-atom Cu with Cu(I)-N₃C₁ sites.Environ Sci Technol2022;56:14797-807

[50] Wang Y,Wen W.Atomically dispersed unsaturated Cu-N₃ sites on high-curvature hierarchically porous carbon nanotube for synergetic enhanced nitrate electroreduction to ammonia.Adv Funct Mater2023;33:2302651

[51] Wang H,Zhan J.P-modified single-atom Cu catalyst boosting electrocatalytic performance of NO₃^- reduction to NH₃.ChemCatChem2023;15:e202201633

[52] Li P,Fang Z,Jin Z.A multifunctional copper single-atom electrocatalyst aerogel for smart sensing and producing ammonia from nitrate.Proc Natl Acad Sci USA2023;120:e2305489120 PMCID:PMC10293845

[53] Yang J,Li A.Potential-driven restructuring of Cu single atoms to nanoparticles for boosting the electrochemical reduction of nitrate to ammonia.J Am Chem Soc2022;144:12062-71

[54] Nielsen SE.Ammonia synthesis: catalyst and technologies. In: Flank WH, Abraham MA, Matthews MA, editors. Innovations in industrial and engineering chemistry. Washington: American Chemical Society; 2008. pp. 15-39.

[55] Yoshino H.Kinetic modeling and simulation of zero-valent iron wastewater treatment process: simultaneous reduction of nitrate, hydrogen peroxide, and phosphate in semiconductor acidic wastewater.Ind Eng Chem Res2013;52:17829-40

[56] Wu ZY,Yong X.Electrochemical ammonia synthesis via nitrate reduction on Fe single atom catalyst.Nat Commun2021;12:2870 PMCID:PMC8128876

[57] Song Q,Hou X.Anchored Fe atoms for N=O bond activation to boost electrocatalytic nitrate reduction at low concentrations.Appl Catal B Environ2022;317:121721

[58] Zhang W,Zhou L.Fe single-atom catalysts with pre-organized coordination structure for efficient electrochemical nitrate reduction to ammonia.Appl Catal B Environ2022;317:121750

[59] Xu J,Liu H.Breaking local charge symmetry of iron single atoms for efficient electrocatalytic nitrate reduction to ammonia.Angew Chem Int Ed2023;62:e202308044

[60] Liu F,An N,Liu X.Highly active electroreduction of nitrates to ammonia over a zeolitic imidazolium framework-derived Fe single-atom catalyst with sulfur-modified asymmetric active centers.J Hazard Mater2024;465:133484

[61] Wang Z,Zhao X.Interfacial defect engineering triggered by single atom doping for highly efficient electrocatalytic nitrate reduction to ammonia.ACS Mater Lett2023;5:1018-26

[62] Zhao J,Liu X.Zn single atom on N-doped carbon: highly active and selective catalyst for electrochemical reduction of nitrate to ammonia.Chem Eng J2023;452:139533

[63] Yang L,Li Y.Frustrated lewis pairs on Zr single atoms supported N-doped TiO_2-x catalysts for electrochemical nitrate reduction to ammonia. Adv Funct Mater 2024:2401094

[64] Ajmal S,Mushtaq MA.Uniting synergistic effect of single-Ni site and electric field of B- bridged-N for boosted electrocatalytic nitrate reduction to ammonia. Small 2024:e2310082

[65] Li J,An N.Boosted ammonium production by single cobalt atom catalysts with high Faradic efficiencies.Proc Natl Acad Sci USA2022;119:e2123450119 PMCID:PMC9303948

[66] Wang C,Stamenkovic VR.Advanced platinum alloy electrocatalysts for the oxygen reduction reaction.ACS Catal2012;2:891-8

[67] Li S,Peng M.Crystal-phase engineering of PdCu nanoalloys facilitates selective hydrodeoxygenation at room temperature.Innovation2022;3:100189 PMCID:PMC8693314

[68] Zhang L,Zhou X.Direct conversion of CO₂ to a jet fuel over CoFe alloy catalysts.Innovation2021;2:100170 PMCID:PMC8523875

[69] Vandevyvere T,Mendes PS,Lauwaert J.NiCu-based catalysts for the low-temperature hydrodeoxygenation of anisole: Effect of the metal ratio on SiO₂ and γ-Al₂O₃ supports.Green Carbon2023;1:170-84

[70] Wang Y,Wang Z.Enhanced nitrate-to-ammonia activity on copper-nickel alloys via tuning of intermediate adsorption.J Am Chem Soc2020;142:5702-8

[71] Du C,Wang J.Selectively reducing nitrate into NH₃ in neutral media by PdCu single-atom alloy electrocatalysis.ACS Catal2023;13:10560-9

[72] Liu H,Zhu C.Efficient electrochemical nitrate reduction to ammonia with copper-supported rhodium cluster and single-atom catalysts.Angew Chem Int Ed2022;61:e202202556

[73] Cai J,Cao A.Electrocatalytic nitrate-to-ammonia conversion with ~100% faradaic efficiency via single-atom alloying.Appl Catal B Environ2022;316:121683

[74] Yin H,Li J.Electrocatalytic reduction of nitrate to ammonia via a Au/Cu single atom alloy catalyst.Environ Sci Technol2023;57:3134-44

[75] Zhang Y,Wang W,Crittenden JC.Electrocatalytic nitrate reduction to ammonia on defective Au1Cu (111) single-atom alloys.Appl Catal B Environ2022;310:121346

[76] Chen K,Li X,Ma D.Single-atom Bi alloyed Pd metallene for nitrate electroreduction to ammonia.Adv Funct Mater2023;33:2209890

[77] Xie M,Li Z.Intermetallic single-atom alloy In-Pd bimetallene for neutral electrosynthesis of ammonia from nitrate.J Am Chem Soc2023;145:13957-67

[78] Wu X,Gupta S.Contrasting capability of single atom palladium for thermocatalytic versus electrocatalytic nitrate reduction reaction.ACS Catal2023;13:6804-12

[79] Ji S,Wang X,Wang D.Chemical synthesis of single atomic site catalysts.Chem Rev2020;120:11900-55

[80] Fei H,Wan C.Microwave-assisted rapid synthesis of graphene-supported single atomic metals.Adv Mater2018;30:e1802146

[81] Zhang L,Sun X.Single-atom catalysts by the atomic layer deposition technique.Natl Sci Rev2018;5:628-30

[82] Qiu HJ,Cong W.Nanoporous graphene with single-atom nickel dopants: an efficient and stable catalyst for electrochemical hydrogen production.Angew Chem Int Ed2015;54:14031-5

[83] Ali H,Guler AC,Machovsky M.Heterojunction-based photocatalytic nitrogen fixation: principles and current progress.Nanoscale Adv2021;3:6358-72 PMCID:PMC9417957

[84] Zhao Y,Bian X.Ammonia detection methods in photocatalytic and electrocatalytic experiments: how to improve the reliability of NH₃ production rates?.Adv Sci2019;6:1802109 PMCID:PMC6468971

[85] Hodgetts RY,Nichols P.Refining universal procedures for ammonium quantification via rapid ¹H NMR analysis for dinitrogen reduction studies.ACS Energy Lett2020;5:736-41

[86] Li Z,Cai Y,Zhu W.Electrochemically reconstructed copper-polypyrrole nanofiber network for remediating nitrate-containing water at neutral pH.J Hazard Mater2022;440:129828

[87] Wendimu G,Mohan BR.Wax screen-based fabrication of paper devices for the determination of iron in particulates of selected welding fumes in Addis Ababa, Ethiopia.Bull Chem Soc Eth2024;38:563-76

[88] Sarma BB,Doronkin DE.Design of single-atom catalysts and tracking their fate using operando and advanced X-ray spectroscopic tools.Chem Rev2023;123:379-444 PMCID:PMC9837826

[89] Wang X,Ma W.Free-standing membrane incorporating single-atom catalysts for ultrafast electroreduction of low-concentration nitrate.Proc Natl Acad Sci USA2023;120:e2217703120 PMCID:PMC10089203

[90] Liu X,Wang H.Lattice confined Ru single sites in hollow Co₉S₈ polyhedron triggering Co-S-Ru catalytic centers for rechargeable Zn-air battery.Nano Res2023;16:6701-9

[91] Sun H,Liao Y.Atomically imaging single atom catalysts and their behaviors by scanning tunneling microscopy.EES Catal2023;1:794-809

[92] Zhang L,Zhang L.Direct visualization of the evolution of a single-atomic cobalt catalyst from melting nanoparticles with carbon dissolution.Adv Sci2022;9:e2200592 PMCID:PMC9284138

[93] Li X,Zhang J,Liu B.In situ/operando techniques for characterization of single-atom catalysts.ACS Catal2019;9:2521-31

[94] Zhang N,Shen P,Ma D.Lewis acid Fe-V pairs promote nitrate electroreduction to ammonia.Adv Funct Mater2023;33:2211537

[95] Song W,Fan X.Recent progress and strategies on the design of catalysts for electrochemical ammonia synthesis from nitrate reduction.Inorg Chem Front2023;10:3489-514

[96] Xiang T,Zeng Y.Transition metal single-atom catalysts for the electrocatalytic nitrate reduction: mechanism, synthesis, characterization, application, and prospects.Small2023;19:e2303732

[97] Wang S,Hui KS.Non-noble single-atom alloy for electrocatalytic nitrate reduction using hierarchical high-throughput screening.Nano Energy2023;113:108543

[98] Niu H,Wang X,Shao C.Theoretical insights into the mechanism of selective nitrate-to-ammonia electroreduction on single-atom catalysts.Adv Funct Mater2021;31:2008533

[99] Zhu S,Chen L.Theoretical investigation of electrocatalytic reduction of nitrates to ammonia on highly efficient and selective g-C₂N monolayer-supported single transition-metal atoms.J Phys Chem Lett2023;14:4185-91

[100] Lai J,Yang X.Opening the black box: Insights into the restructuring mechanism to steer catalytic performance.Innov Mater2023;1:100020

[101] Bai X,Zhang Y.Dynamic stability of copper single-atom catalysts under working conditions.J Am Chem Soc2022;144:17140-8

[102] Zhang H,Shi L.Single-atom catalysts: emerging multifunctional materials in heterogeneous catalysis.Adv Energy Mater2018;8:1701343

[103] Liberto G, Pacchioni G. Modeling single-atom catalysis.Adv Mater2023;35:e2307150

[104] Burke K.DFT in a nutshell.Int J of Quantum Chem2013;113:96-101

[105] Wang Y,Shao M.First-principles mechanistic study on nitrate reduction reactions on copper surfaces: effects of crystal facets and pH.J Catal2021;400:62-70

[106] Tu X,Bo S.A universal approach for sustainable urea synthesis via intermediate assembly at the electrode/electrolyte interface.Angew Chem Int Ed2024;63:e202317087