Bamboo-like N-doped carbon nanotubes encapsulating M(Co, Fe)-Ni alloy for electrochemical production of syngas with potential-independent CO/H₂ ratios

Abstract

The electrochemical conversion of CO₂-H₂O into CO-H₂ using renewable energy is a promising technique for clean syngas production. Low-cost electrocatalysts to produce tunable syngas with a potential-independent CO/H₂ ratio are highly desired. Herein, a series of N-doped carbon nanotubes encapsulating binary alloy nanoparticles (M_xNi-NCNT, M= Fe, Co) were successfully fabricated through the co-pyrolysis of melamine and metal precursors. The M_xNi-NCNT samples exhibited bamboo-like nanotubular structures with a large specific surface area and high degree of graphitization. Their electrocatalytic performance for syngas production can be tuned by changing the alloy compositions and modifying the electronic structure of the carbon nanotube through the encapsulated metal nanoparticles. Consequently, syngas with a wide range of CO/H₂ ratios, from 0.5:1 to 3.4:1, can be produced on M_xNi-NCNT. More importantly, stable CO/H₂ ratios of 2:1 and 1.5:1, corresponding to the ratio to produce biofuels by syngas fermentation, could be realized on Co₁Ni-NCNT and Co₂Ni-NCNT, respectively, over a potential window of –0.8 to –1.2 V versus the reversible hydrogen electrode. Our work provides an approach to develop low-cost and potential-independent electrocatalysts to effectively produce syngas with an adjustable CO/H₂ ratio from electrochemical CO₂ reduction.

Key words： electrochemical reduction of CO₂; syngas; N-doped carbon nanotubes; encapsulated alloy nanoparticles; CO/H₂ ratio

Acknowledgments

This research was funded by the National Natural Science Foundation of China (Grant Nos. 21873067 and 21206117). We are grateful to the analysis and test center of Tianjin University for providing physical characterizations (XRD, SEM, TEM, XPS).

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://dx.doi.org/10.1007/s11705-021-2082-6 and is accessible for authorized users.

References

1 Hsieh T, Zhang Y, Xu D, Wang C, Pickarts M, Chung C, Fan L, Tong A. Chemical looping gasification for producing high purity, H₂-rich syngas in a cocurrent moving bed reducer with coal and methane cofeeds. Industrial & Engineering Chemistry Research, 2018, 57(7): 2461–2475

2 Lu S, Shi Y, Meng N, Lu S, Yu Y, Zhang B. Electrosynthesis of syngas via the co-reduction of CO₂ and H₂O. Cell Reports Physical Science, 2020, 1(11): 100237

3 Cui S, Yu C, Tan X, Huang H, Yao X, Qiu J. Achieving multiple and tunable ratios of syngas to meet various downstream industrial processes. ACS Sustainable Chemistry & Engineering, 2020, 8(8): 3328–3335

4 Li H, Xiao N, Wang Y, Li C, Ye X, Guo Z, Pan X, Liu C, Bai J, Xiao J, . Nitrogen-doped tubular carbon foam electrodes for efficient electroreduction of CO₂ to syngas with potential-independent CO/H₂ ratios. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 2019, 7(32): 18852–18860

5 Qin B, Li Y, Fu H, Wang H, Chen S, Liu Z, Peng F. Electrochemical reduction of CO₂ into tunable syngas production by regulating the crystal facets of earth-abundant Zn catalyst. ACS Applied Materials & Interfaces, 2018, 10(24): 20530–20539

6 Cho M, Seo J, Song J T, Lee J, Oh J. Silver nanowire/carbon sheet composites for electrochemical syngas generation with tunable H₂/CO ratios. ACS Omega, 2017, 2(7): 3441–3446

7 Yao X, Guo Y, Liu B, Wang P, Sun J, Li W, Zhao C. Syngas production from electrochemical CO₂ reduction on copper oxide electrodes in aqueous solution. ChemElectroChem, 2021, 8(3): 592–602

8 Lv K, Teng C, Shi M, Yuan Y, Zhu Y, Wang J, Kong Z, Lu X, Zhu Y. Hydrophobic and electronic properties of the E-MoS₂ nanosheets induced by FAS for the CO₂ electroreduction to syngas with a wide range of CO/H₂ ratios. Advanced Functional Materials, 2018, 28(49): 1802339

9 Wang J, Huang H, Sun J, Zhong D, Lu T. Syngas production with a highly-robust nickel(II) homogeneous electrocatalyst in a water-containing system. ACS Catalysis, 2018, 8(8): 7612–7620

10 Dong B, Qian S, Bu F, Wu Y, Feng L, Teng Y, Liu W, Li Z. Electrochemical reduction of CO₂ to CO by a heterogeneous catalyst of Fe-porphyrin-based metal-organic framework. ACS Applied Energy Materials, 2018, 1(9): 4662–4669

11 Daiyan R, Chen R, Kumar P, Bedford N M, Qu J, Cairney J M, Lu X, Amal R. Tunable syngas production through CO₂ electroreduction on cobalt-carbon composite electrocatalyst. ACS Applied Materials & Interfaces, 2020, 12(8): 9307–9315

12 He Q, Liu D, Lee J H, Liu Y, Xie Z, Hwang S, Kattel S, Song L, Chen J G. Electrochemical conversion of CO₂ to syngas with controllable CO/H₂ ratios over Co and Ni single-atom catalysts. Angewandte Chemie International Edition, 2020, 59(8): 3033–3037

13 Meng N, Zhou W, Yu Y, Liu Y, Zhang B. Superficial hydroxyl and amino groups synergistically active polymeric carbon nitride for CO₂ electroreduction. ACS Catalysis, 2019, 9(12): 10983–10989

14 Xie J, Zhao X, Wu M, Li Q, Wang Y, Yao J. Metal-free fluorine-doped carbon electrocatalyst for CO₂ reduction outcompeting hydrogen evolution. Angewandte Chemie International Edition, 2018, 130(31): 9788–9792

15 Lamaison S, Wakerley D, Montero D, Rousse G, Taverna D, Giaume D, Mercier D, Blanchard J, Tran H N, Fontecave M, . Zn-Cu alloy nanofoams as efficient catalysts for the reduction of CO₂ to syngas mixtures with a potential-independent H₂/CO ratio. ChemSusChem, 2019, 12(2): 511–517

16 Yang W, Zhang J, Si R, Cao L, Zhong D, Lu T. Efficient and steady production of 1:2 syngas (CO/H₂) by simultaneous electrochemical reduction of CO₂ and H₂O. Inorganic Chemistry Frontiers, 2021, 8(7): 1695–1701

17 Tao L, Wang Y, Zou Y, Zhang N, Zhang Y, Wu Y, Wang Y, Chen R, Wang S. Charge transfer modulated activity of carbon-based electrocatalysts. Advanced Energy Materials, 2019, 10(11): 1901227

18 Miao Z, Meng J, Liang M, Li Z, Zhao Y, Wang F, Xu L, Mu J, Zhuo S, Zhou J. In-situ CVD synthesis of Ni@N-CNTs/carbon paper electrode for electro-reduction of CO₂. Carbon, 2021, 172: 324–333

19 Zheng W, Guo C, Yang J, He F, Yang B, Li Z, Lei L, Xiao J, Wu G, Hou Y. Highly active metallic nickel sites confined in N-doped carbon nanotubes toward significantly enhanced activity of CO₂ electroreduction. Carbon, 2019, 150: 52–59

20 Zhang S, Wu Q, Tang L, Hu Y, Wang M, Zhao J, Li M, Han J, Liu X, Wang H. Individual high-quality N-doped carbon nanotubes embedded with nonprecious metal nanoparticles toward electrochemical reaction. ACS Applied Materials & Interfaces, 2018, 10(46): 39757–39767

21 Niu Y, Zhang C, Wang Y, Fang D, Zhang L, Wang C. Confining chainmail-bearing Ni nanoparticles in N-doped carbon nanotubes for robust and efficient electroreduction of CO₂. ChemSusChem, 2021, 14(4): 1140–1154

22 Daiyan R, Lu X, Tan X, Zhu X, Chen R, Smith S C, Amal R. Antipoisoning nickel-carbon electrocatalyst for practical electrochemical CO₂ reduction to CO. ACS Applied Energy Materials, 2019, 2(11): 8002–8009

23 Hu Y, Jensen J O, Zhang W, Cleemann L N, Xing W, Bjerrum N J, Li Q. Hollow spheres of iron carbide nanoparticles encased in graphitic layers as oxygen reduction catalysts. Angewandte Chemie International Edition, 2014, 53(14): 3675–3679

24 Deng J, Yu L, Deng D, Chen X, Yang F, Bao X. Highly active reduction of oxygen on a FeCo alloy catalyst encapsulated in pod-like carbon nanotubes with fewer walls. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 2013, 1(47): 14868

25 Xiang D, Bo X, Gao X, Zhang C, Du C, Zheng F, Zhuang Z, Li P, Zhu L, Chen W. Novel one-step synthesis of core@shell iron–nickel alloy nanoparticles coated by carbon layers for efficient oxygen evolution reaction electrocatalysis. Journal of Power Sources, 2019, 438: 226988

26 Tu Y, Ren P, Deng D, Bao X. Structural and electronic optimization of graphene encapsulating binary metal for highly efficient water oxidation. Nano Energy, 2018, 52: 494–500

27 Ou Y, Tian W, Liu L, Zhang Y, Xiao P. Bimetallic Co₂Mo₃O₈ suboxides coupled with conductive cobalt nanowires for efficient and durable hydrogen evolution in alkaline electrolyte. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 2018, 6(12): 5217–5228

28 Chen M, Zhao G, Shao L, Yuan Z, Jing Q, Huang K, Huang Z, Zhao X, Zou G. Controlled synthesis of nickel encapsulated into nitrogen-doped carbon nanotubes with covalent bonded interfaces: the structural and electronic modulation strategy for an efficient electrocatalyst in dye-sensitized solar cells. Chemistry of Materials, 2017, 29(22): 9680–9694

29 Chen L, Xu Z, Han W, Zhang Q, Bai Z, Chen Z, Li G, Wang X. Bimetallic CoNi alloy nanoparticles embedded in pomegranate-like nitrogen-doped carbon spheres for electrocatalytic oxygen reduction and evolution. ACS Applied Nano Materials, 2020, 3(2): 1354–1362

30 Xie Y, Feng C, Guo Y, Li S, Guo C, Zhang Y, Wang J. MOFs derived carbon nanotubes coated CoNi alloy nanocomposites with N-doped rich-defect and abundant cavity structure as efficient trifunctional electrocatalyst. Applied Surface Science, 2021, 536: 147786

31 Zhao J, Deng J, Han J, Imhanria S, Chen K, Wang W. Effective tunable syngas generation via CO₂ reduction reaction by non-precious Fe-N-C electrocatalyst. Chemical Engineering Journal, 2020, 389: 124323

32 Yang L, Wang D, Lv Y, Cao D. Nitrogen-doped graphitic carbons with encapsulated CoNi bimetallic nanoparticles as bifunctional electrocatalysts for rechargeable Zn-air batteries. Carbon, 2019, 144: 8–14

33 Shen Y, Zhou Y, Wang D, Wu X, Li J, Xi J. Nickel-copper alloy encapsulated in graphitic carbon shells as electrocatalysts for hydrogen evolution reaction. Advanced Energy Materials, 2018, 8(2): 1701759

34 Tong M, Wang L, Yu P, Liu X, Fu H. 3D network nanostructured NiCoP nanosheets supported on N-doped carbon coated Ni foam as a highly active bifunctional electrocatalyst for hydrogen and oxygen evolution reactions. Frontiers of Chemical Science and Engineering, 2018, 12(3): 417–424

35 Li L, Huang Y, Li Y. Carbonaceous materials for electrochemical CO₂ reduction. EnergyChem, 2020, 2(1): 100024

36 Li G, Xu X, Yang B, Cao S, Wang X, Fu X, Shi Y, Yan Y, Song X, Hao C. Micelle-template synthesis of a 3D porous FeNi alloy and nitrogen-codoped carbon material as a bifunctional oxygen electrocatalyst. Electrochimica Acta, 2020, 331: 135375

37 Ma X, Chai H, Cao Y, Xu J, Wang Y, Dong H, Jia D, Zhou W. An effective bifunctional electrocatalysts: controlled growth of CoFe alloy nanoparticles supported on N-doped carbon nanotubes. Journal of Colloid and Interface Science, 2018, 514: 656–663

38 Wang Z, Ang J, Liu J, Ma X Y D, Kong J, Zhang Y, Yan T, Lu X. FeNi alloys encapsulated in N-doped CNTs-tangled porous carbon fibers as highly efficient and durable bifunctional oxygen electrocatalyst for rechargeable zinc-air battery. Applied Catalysis B: Environmental, 2020, 263: 118344

39 Wu M, Guo B, Nie A, Liu R. Tailored architectures of FeNi alloy embedded in N-doped carbon as bifunctional oxygen electrocatalyst for rechargeable zinc-air battery. Journal of Colloid and Interface Science, 2020, 561: 585–592

40 Liu P, Gao D, Xiao W, Ma L, Sun K, Xi P, Xue D, Wang J. Self-powered water-splitting devices by core-shell NiFe@N-graphite-based Zn-air batteries. Advanced Functional Materials, 2018, 28(14): 1706928

41 Gao Z, Wang L, Chang J, Chen C, Wu D, Xu F, Jiang K. CoNi alloy incorporated, N doped porous carbon as efficient counter electrode for dye-sensitized solar cell. Journal of Power Sources, 2017, 348: 158–167

42 Gebremariam T T, Chen F, Jin Y, Wang Q, Wang J, Wang J. Bimetallic NiCo/CNF encapsulated in a N-doped carbon shell as an electrocatalyst for Zn-air batteries and water splitting. Catalysis Science & Technology, 2019, 9(10): 2532–2542

43 Cui X, Ren P, Deng D, Deng J, Bao X. Single layer graphene encapsulating non-precious metals as high-performance electrocatalysts for water oxidation. Energy & Environmental Science, 2016, 9(1): 123–129

44 Yang H B, Hung S, Liu S, Yuan K, Miao S, Zhang L, Huang X, Wang H, Cai W, Chen R, . Atomically dispersed Ni(I) as the active site for electrochemical CO₂ reduction. Nature Energy, 2018, 3(2): 140–147

45 Li X, Bi W, Chen M, Sun Y, Ju H, Yan W, Zhu J, Wu X, Chu W, Wu C, . Exclusive Ni–N₄ sites realize near-unity CO selectivity for electrochemical CO₂ reduction. Journal of the American Chemical Society, 2017, 139(42): 14889–14892

46 Gao C, Lyu F, Yin Y. Encapsulated metal nanoparticles for catalysis. Chemical Reviews, 2021, 121(2): 834–881

47 Pradeep C M, Samir K K. Biomass-derived syngas fermentation into biofuels: opportunities and challenges. Bioresource Technology, 2010, 101(13): 5013–5022

48 Wang Y, Niu C, Zhu Y, He D, Huang W. Tunable syngas formation from electrochemical CO₂ reduction on copper nanowire arrays. ACS Applied Energy Materials, 2020, 3(10): 9841–9847

49 Zhang C, Liu J, Ye Y, Chen Q, Liang C. Encapsulation of Co-based nanoparticle in N-doped graphitic carbon for efficient oxygen reduction reaction. Carbon, 2020, 156: 31–37