Modulating electronic structure of Co-N₅S₁ sites in Co single atom catalysts via phosphorus incorporation and nanoclusters to promote oxygen electrocatalytic activity

Abstract

Atomically dispersed metal catalysts coordinated with nitrogen coordination and anchored to carbon substrates (M-N-C) have become highly effective alternatives to platinum-group catalysts for oxygen electrocatalysis. However, the catalytic efficacy of M-N-C systems remains constrained by the suboptimal performance associated with the symmetric charge distribution around the active metal centers. The synergistic co-design of asymmetric metal single-atom catalytic centers with heteroatom doping significantly enhances the bifunctional oxygen electrocatalytic activity and durability, advancing the capabilities of next-generation flexible zinc-air batteries. Herein, we developed a pyrolysis-secondary coordination strategy to generate a bifunctional oxygen electrocatalyst, characterized by single Co atoms integrated within an asymmetrical Co-N₅S₁ moiety, along with nanocluster complexes embedded in N,P,S-codoped carbon frameworks, labeled Co_SA+NC/NPSC. In the Co_SA+NC/NPSC catalyst, the Co-N₅S₁ active sites exhibit an optimized electronic configuration, achieved through the synergistic coordination of heteroatom doping and nanocluster integration. Theoretically, this configuration significantly lowers the energy barriers and adjusts the d-band center, ensuring a more balanced binding strength between active sites and the oxygen-containing intermediates and contributing to the promoted bifunctional oxygen reduction reaction/oxygen evolution reaction efficiency. The experimentally analytical results reveal that the Co_SA+NC/NPSC demonstrates an impressive oxygen evolution reaction activity (E_j=10 = 1.58 V) and a narrow bifunctional potential gap (ΔE = 0.75 V), remarkably superior to the counterparts with symmetric Co-S coordination or phosphorus-free doping. When assembled as an air electrode, the Co_SA+NC/NPSC-based flexible zinc-air battery exhibits ultralong charge-discharge life (> 105 h) and impressive initial round-trip efficiency of 72.42% even at 0 °C.

Keywords

Asymmetric metal single-atom / heteroatom doping / bifunctional oxygen electrocatalyst / flexible zinc-air battery

References

[1] Xia Q,Zhao L.Carbon-supported single-atom catalysts for advanced rechargeable metal-air batteries.Energy Mater2022;2:200015:

[2] Worku A,Habtu N.Recent advances and future perspectives in engineering of bifunctional electrocatalysts for rechargeable zinc-air batteries.Mater Today Adv2021;9:100116

[3] Ryu J,Park J,Park M.Molecular engineering of atomically dispersed Fe-N₄ and Cu-N₄ dual-sites in carbon nitride nanotubes for rechargeable zinc-air batteries.Energy Storage Mater2023;55:397-405

[4] Liu C,Zhou Y.The recent progress of single-atom catalysts on amorphous substrates for electrocatalysis.Energy Mater2024;4:500001

[5] Ji S,Liu H.Regulating the electronic synergy of asymmetric atomic Fe sites with adjacent defects for boosting activity and durability toward oxygen reduction.Adv Funct Mater2024;34:2314621

[6] Qiu G,Qiao H.Construction of Fe/Co-N₄ single-atom sites for the oxygen reduction reaction in zinc-air batteries.Inorg Chem2024;63:17955-66

[7] Lv M,Huang N.Precisely engineering asymmetric atomic CoN₄ by electron donating and extracting for oxygen reduction reaction.Angew Chem Int Ed2024;63:e202315802

[8] Deng W,Wu Y.Microcosmic modulation of the Co-N bonding structure improves the multi-functional electrocatalytic performance.J Mater Chem A2024;12:10349-58

[9] Cui T,Ye T.Engineering dual single-atom sites on 2D ultrathin N-doped carbon nanosheets attaining ultra-low-temperature zinc-air battery.Angew Chem Int Ed2022;61:e202115219

[10] Tong M,Xing G,Wang L.Potential dominates structural recombination of single atom Mn sites for promoting oxygen reduction reaction.Angew Chem Int Ed2023;62:e202314933

[11] Chen K,An P.Iron phthalocyanine with coordination induced electronic localization to boost oxygen reduction reaction.Nat Commun2020;11:4173 PMCID:PMC7441147

[12] Chen Z,Ding J.Unraveling the origin of sulfur-doped Fe-N-C single-atom catalyst for enhanced oxygen reduction activity: effect of iron spin-state tuning.Angew Chem Int Ed2021;60:25404-10

[13] Ramaswamy N,Jia Q.Activity descriptor identification for oxygen reduction on nonprecious electrocatalysts: linking surface science to coordination chemistry.J Am Chem Soc2013;135:15443-9

[14] Yasin G,Ibraheem S.Simultaneously engineering the synergistic-effects and coordination-environment of dual-single-atomic iron/cobalt-sites as a bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries.ACS Catal2023;13:2313-25

[15] Li M,Yuan Q.Proximity electronic effect of Ni/Co diatomic sites for synergistic promotion of electrocatalytic oxygen reduction and hydrogen evolution.Adv Funct Mater2023;33:2210867

[16] Wang Y,Tang S.Synergistic Fe-Se atom pairs as bifunctional oxygen electrocatalysts boost low-temperature rechargeable Zn-air battery.Angew Chem Int Ed2023;62:e202219191

[17] Wu S,Liu S.Single Cu-N₄ sites enable atomic Fe clusters with high-performance oxygen reduction reactions.Energy Environ Sci2023;16:3576-86

[18] Chen Y,Liu Q.Highly durable iron single-atom catalysts for low-temperature zinc-air batteries by electronic regulation of adjacent iron nanoclusters.Appl Catal B Environ2023;323:122163

[19] Zhang J,Qiu C.Boosting activity of Fe-N₄ sites in single-Fe-atom catalysts via S in the second coordination sphere for direct methanol fuel cells.Cell Rep Phys Sci2023;4:101330

[20] Zhao Y,Huo J.Epoxy-rich Fe single atom sites boost oxygen reduction electrocatalysis.Angew Chem Int Ed2023;62:e202308349

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

[22] Li Z,Gao L.Asymmetric coordination of bimetallic Fe-Co single-atom pairs toward enhanced bifunctional activity for rechargeable zinc-air batteries.ACS Nano2024;18:13006-18

[23] Yang Y,Liang Y.Hetero-diatomic CoN₄-NiN₄ site pairs with long-range coupling as efficient bifunctional catalyst for rechargeable Zn-air batteries.Adv Sci2024;11:e2310231

[24] Li X,Lin Q.Electron spin broken-symmetry of Fe-Co diatomic pairs to promote kinetics of bifunctional oxygen electrocatalysis for zinc-air batteries.Adv Sci2024;11:e2401187

[25] Rao P,Fan W.Movable type printing method to synthesize high-entropy single-atom catalysts.Nat Commun2022;13:5071 PMCID:PMC9424199

[26] Shang H,Dong J.Engineering unsymmetrically coordinated Cu-S₁N₃ single atom sites with enhanced oxygen reduction activity.Nat Commun2020;11:3049 PMCID:PMC7297793

[27] Guan G,Li F.Atomic cobalt metal centers with asymmetric N/B-coordination for promoting oxygen reduction reaction.Adv Funct Mater2024;34:2408111

[28] Zhou Y,Wang Z.Fe-Co dual atomic doublets on N, P codoped carbon as active sites in the framework of heterostructured hollow fibers towards high-performance flexible Zn-air battery.Energy Storage Mater2023;59:102772

[29] Sheng J,Jia G,Li Y.Doping effect on mesoporous carbon-supported single-site bifunctional catalyst for zinc-air batteries.ACS Nano2022;16:15994-6002

[30] Zhou Y,Tao X.Boosting oxygen electrocatalytic activity of Fe-N-C catalysts by phosphorus incorporation.J Am Chem Soc2023;145:3647-55

[31] Wang Z,Xu R.Cooperation between dual metal atoms and nanoclusters enhances activity and stability for oxygen reduction and evolution.ACS Nano2023;17:8622-33

[32] Wan X,Liu J.Iron atom-cluster interactions increase activity and improve durability in Fe-N-C fuel cells.Nat Commun2022;13:2963

[33] Ao X,Li Z.Markedly enhanced oxygen reduction activity of single-atom Fe catalysts via integration with Fe nanoclusters.ACS Nano2019;13:11853-62

[34] Yang HG,Qiao SZ.Anatase TiO₂ single crystals with a large percentage of reactive facets.Nature2008;453:638-41

[35] Perdew JP,Ernzerhof M.Generalized gradient approximation made simple.Phys Rev Lett1996;77:3865

[36] Schimka L,Stroppa A.Accurate surface and adsorption energies from many-body perturbation theory.Nat Mater2010;9:741-4

[37] Chadi DJ.Special points for brillouin-zone integrations.Phys Rev B1976;13:5188

[38] Tan Y,Li A,Zhang Y.Double synergetic FeCo-nanoparticles and single atoms embedded in N-doped carbon nanotube arrays as efficient bifunctional catalyst for high-performance zinc-air batteries.Mater Today Energy2022;29:101138

[39] Wang Z,Ye Q.Construction of Fe nanoclusters/nanoparticles to engineer FeN₄ sites on multichannel porous carbon fibers for boosting oxygen reduction reaction.Adv Funct Mater2024;34:2315150

[40] Liu S,Wang C.Turning main-group element magnesium into a highly active electrocatalyst for oxygen reduction reaction.Nat Commun2020;11:938 PMCID:PMC7028951

[41] Wang P,Wang K.Simultaneously constructing asymmetrically coordinated cobalt single atoms and cobalt nanoclusters via a fresh potassium hydroxide clipping strategy toward efficient alkaline oxygen Rreduction reaction.Energy Mater Adv2023;4:0042