Sulfur-deficient CoNi₂S₄ nanoparticles-anchored porous carbon nanofibers as bifunctional electrocatalyst for overall water splitting

Abstract

Water electrolysis technology is considered to be one of the most promising means to produce hydrogen. Herein, aiming at the problems of high overpotential and slow kinetics in water splitting, N-doped porous carbon nanofibers-coupled CoNi₂S₄ nanoparticles are prepared as bifunctional electrocatalyst. In the strategy, NaCl is used as the template to prepare porous carbon nanofibers with a large surface area, and sulfur vacancies are created to modulate the electronic structure of CoNi₂S₄. Electron spin resonance confirms the formation of abundant sulfur vacancies, which largely reduce the bandgap of CoNi₂S₄ from 1.68 to 0.52 eV. The narrowed bandgap is conducive to the migration of valence electrons and decreases the charge transfer resistance for electrocatalytic reaction. Moreover, the uniform distribution of CoNi₂S₄ nanoparticles on carbon nanofibers can prevent the aggregation and facilitate the exposure of electrochemical active sites. Therefore, the composite catalyst exhibits low overpotentials of 340 mV@100 mA·cm^–2 for oxygen evolution reaction and 380 mV@100 mA·cm^–2 for hydrogen evolution reaction. The assembled electrolyzer requires 1.64 V to achieve 10 mA·cm^–2 for overall water-splitting with good long-term stability. The excellent performance results from the synergistic effect of porous structures, sulfur deficiency, nitrogen doping, and the well-dispersed active component.

Key words： nanoparticle; sulfur vacancy; porous carbon nanofiber; transition metal sulfides; electrolysis

Conflicts of interest

There are no conflicts to declare.

Acknowledgements

The authors gratefully acknowledge the financial supports from Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering (Grant No. 2022SX-TD003) and the National Natural Science Foundation of China (Grant Nos. U2032131 and 52102048).

References

1 Yu X H, Yi J L, Zhang R L, Wang F Y, Liu L. Hollow carbon spheres and their noble metal-free hybrids in catalysis. Frontiers of Chemical Science and Engineering, 2021, 15(6): 1380–1407

2 Yan C Y, Li W Q, Liu X J, Chen M, Liu X, Li X M, Zai J T, Qian X F. Donor-π-acceptor heterosystem-functionalized porous hollow carbon microsphere for high-performance Li–S cathode materials with S up to 93 wt %. ACS Applied Materials & Interfaces, 2021, 13(41): 48872–48880

3 Han D, Du G H, Wang Y T, Jia L N, Zhao W Q, Su Q M, Ding S K, Zhang M, Xu B S. Chemical energy-driven lithiation preparation of defect-rich transition metal nanostructures for electrocatalytic hydrogen evolution. Small, 2022, 18(35): 2202779

4 Wang H, Weng C, Ren J T, Yuan Z Y. An overview and recent advances in electrocatalysts for direct seawater splitting. Frontiers of Chemical Science and Engineering, 2021, 15(6): 1408–1426

5 Li J Q, Zhu Z X, Huang Y C, Wang F, Balogun M S. Ni₃N: a multifunctional material for energy storage and electrocatalysis. Materials Today. Energy, 2022, 26: 101001

6 Hu L, Hu Y W, Liu R, Mao Y C, Balogun M S, Tong Y X. Co-based MOF-derived Co/CoN/Co₂P ternary composite embedded in N- and P-doped carbon as bifunctional nanocatalysts for efficient overall water splitting. International Journal of Hydrogen Energy, 2019, 44(23): 11402–11410

7 Xiong T, Yao X, Zhu Z, Xiao R, Hu Y W, Huang Y, Zhang S, Balogun M S. In situ grown Co-based interstitial compounds: non-3d metal and non-metal dual modulation boosts alkaline and acidic hydrogen electrocatalysis. Small, 2022, 18(9): 2105331

8 Feng X, Jiao Q, Cui H, Yin M, Li Q, Zhao Y, Li H, Zhou W, Feng C. One-pot synthesis of NiCo₂S₄ hollow spheres via sequential ion-exchange as an enhanced oxygen bifunctional electrocatalyst in alkaline solution. ACS Applied Materials & Interfaces, 2018, 10(35): 29521–29531

9 He K, Tadesse Tsega T, Liu X, Zai J, Li X H, Liu X, Li W, Ali N, Qian X. Utilizing the space-charge region of the FeNi-LDH/CoP p–n junction to promote performance in oxygen evolution electrocatalysis. Angewandte Chemie International Edition, 2019, 58(34): 11903–11909

10 Ali N, Tsega T T, Cao Y C, Abbas S, Li W J, Iqbal A, Fazal H, Xin Z L, Zai J T, Qian X F. Copper vacancy activated plasmonic Cu_3−xSnS₄ for highly efficient photocatalytic hydrogen generation: broad solar absorption, efficient charge separation and decreased HER overpotential. Nano Research, 2021, 14(10): 3358–3364

11 Jia L N, Du G H, Han D, Wang Y, Zhao W Q, Su Q M, Ding S K, Xu B S. Magnetic electrode configuration with polypyrrole-wrapped Ni/NiFe₂O₄ core–shell nanospheres to boost electrocatalytic water splitting. Chemical Engineering Journal, 2023, 454: 140278

12 Guo J, Wang M, Xu L, Li X, Iqba A, Sterbinsky G E, Yan H, Xie M, Zai J, Feng Z, Cheng T, Qian X. Bioinspired activation of N₂ on asymmetrical coordinated Fe grafted 1T MoS₂ at room temperature. Chinese Journal of Chemistry, 2021, 39(7): 1898–1904

13 Guo J J, Tsega T T, Islam I U, Iqbal A, Zai J, Qian X F. Fe doping promoted electrocatalytic N₂ reduction reaction of 2H MoS₂. Chinese Chemical Letters, 2020, 31(9): 2487–2490

14 Qiao X, Jin J, Fan H, Li Y, Liao S. In situ growth of cobalt sulfide hollow nanospheres embedded in nitrogen and sulfur co-doped graphene nanoholes as a highly active electrocatalyst for oxygen reduction and evolution. Journal of Materials Chemistry A, 2017, 5(24): 12354–12360

15 Xiong T Z, Huang B W, Wei J J, Yao X C, Xiao R, Zhu Z X, Yang F, Huang Y C, Yang H, Balogun M S. Unveiling the promotion of accelerated water dissociation kinetics on the hydrogen evolution catalysis of NiMoO₄ nanorods. Journal of Energy Chemistry, 2022, 67: 805–813

16 Xue Y, Zuo Z, Li Y, Liu H, Li Y. Graphdiyne-supported NiCo₂S₄ nanowires: a highly active and stable 3D bifunctional electrode material. Small, 2017, 13(31): 1700936

17 Zhang J, Qu L, Shi G, Liu J, Chen J, Dai L N. P-codoped carbon networks as efficient metal-free bifunctional catalysts for oxygen reduction and hydrogen evolution reactions. Angewandte Chemie, 2016, 128(6): 2270–2274

18 Chen S, Duan J, Jaroniec M, Qiao S Z. Nitrogen and oxygen dual-doped carbon hydrogel film as a substrate-free electrode for highly efficient oxygen evolution reaction. Advanced Materials, 2014, 26(18): 2925–2930

19 Zheng Y, Jiao Y, Li L H, Xing T, Chen Y, Jaroniec M, Qiao S. Toward design of synergistically active carbon-based catalysts for electrocatalytic hydrogen evolution. ACS Nano, 2014, 8(5): 5290–5296

20 Qu K, Zheng Y, Zhang X, Davey K, Dai S, Qiao S Z. Promotion of electrocatalytic hydrogen evolution reaction on nitrogen-doped carbon nanosheets with secondary heteroatoms. ACS Nano, 2017, 11(7): 7293–7300

21 Ma G, Wang X. Synthesis and applications of one-dimensional porous nanowire arrays: a review. Nano, 2015, 10(1): 1530001

22 Wang J, Xu F, Jin H, Chen Y, Wang Y. Non-noble metal-based carbon composites in hydrogen evolution reaction: fundamentals to applications. Advanced Materials, 2017, 29(14): 160583

23 Yan X, Zhuang L, Zhu Z, Yao X. Defect engineering and characterization of active sites for efficient electrocatalysis. Nanoscale, 2021, 13(6): 3327–3345

24 Hao Y, Du G H, Fan Y, Jia L, Han D, Zhao W, Su Q M, Ding S, Xu B S. Mo/P dual-doped Co/oxygen-deficient Co₃O₄ core–shell nanorods supported on Ni foam for electrochemical overall water splitting. ACS Applied Materials & Interfaces, 2021, 13(46): 55263–55271

25 Zhang L F, Ke X, Ou G, Wei H, Wang L N, Wu H. Defective MoS₂ electrocatalyst for highly efficient hydrogen evolution through a simple ball-milling method. Science China Materials, 2017, 60(9): 849–856

26 Basu M. Nanotubes of NiCo₂S₄/Co₉S₈ heterostructure: efficient hydrogen evolution catalyst in alkaline medium. Chemistry-an Asian Journal, 2018, 13(21): 3204–3211

27 Merki D, Fierro S, Vrubel H, Hu X L. Amorphous molybdenum sulfide films as catalysts for electrochemical hydrogen production in water. Chemical Science, 2011, 2(7): 1262–1267

28 Li R, Liu F, Zhang Y, Guo M, Liu D. Nitrogen, sulfur co-doped hierarchically porous carbon as a metal-free electrocatalyst for oxygen reduction and carbon dioxide reduction reaction. ACS Applied Materials & Interfaces, 2020, 12(40): 44578–44587

29 Su P, Jiao Q, Li H, Li Y, Liu X, Wu Q, Shi D, Zhao Y, Wang T, Wang W. Rational design of NiCo₂S₄ quantum dot-modified nitrogen-doped carbon nanotube composites as robust Pt-free electrocatalysts for dye-sensitized solar cells. ACS Applied Energy Materials, 2021, 4(5): 4344–4354

30 Sharma S, Ganguly A, Papakonstantinou P, Miao X, Li M, Hutchison J, Delichatsios M, Ukleja S. Rapid microwave synthesis of CO tolerant reduced graphene oxide-supported platinum electrocatalysts for oxidation of methanol. Journal of Physical Chemistry C, 2010, 114(45): 19459–19466

31 Wang Y, Wei H, Lv H, Chen Z, Zhang J, Yan X, Lee L, Wang Z, Chueh Y L. Highly stable three-dimensional nickel-cobalt hydroxide hierarchical heterostructures hybridized with carbon nanotubes for high-performance energy storage devices. ACS Nano, 2019, 13(10): 11235–11248

32 Cao X, He J, Li H, Kang L, He X, Sun J, Jiang R, Xu H, Lei Z, Liu Z H. CoNi₂S₄ nanoparticle/carbon nanotube sponge cathode with ultrahigh capacitance for highly compressible asymmetric supercapacitor. Small, 2018, 14(27): e1800998

33 Yang Y J, Yao C, Chen S, Wang N, Yang P, Jiang C, Liu M, Cheng Y. A 3D flower-like CoNi₂S₄/carbon nanotube nanosheet arrays grown on Ni foam as a binder-free electrode for asymmetric supercapacitors. Journal of Electroanalytical Chemistry, 2021, 888: 115217

34 Dong M, Hu H, Ding S, Wang C, Li L. Flexible non-enzymatic glucose biosensor based on CoNi₂S₄ nanosheets grown on nitrogen-doped carbon foam substrate. Journal of Alloys and Compounds, 2021, 883: 160830

35 Hu W, Chen R, Xie W, Zou L, Qin N, Bao D. CoNi₂S₄ nanosheet arrays supported on nickel foams with ultrahigh capacitance for aqueous asymmetric supercapacitor applications. ACS Applied Materials & Interfaces, 2014, 6(21): 19318–19326

36 Hu E, Ning J, Zhao D, Xu C, Lin Y, Zhong Y, Zhang Z, Wang Y, Hu Y. A room-temperature postsynthetic ligand exchange strategy to construct mesoporous Fe-doped CoP hollow triangle plate arrays for efficient electrocatalytic water splitting. Small, 2018, 14(14): e1704233

37 Lin J, Wang P, Wang H, Li C, Si X, Qi J, Cao J, Zhong Z, Fei W, Feng J. Defect-rich heterogeneous MoS₂/NiS₂ nanosheets electrocatalysts for efficient overall water splitting. Advancement of Science, 2019, 6(14): 1900246

38 Li Z, Zhao D, Xu C, Ning J, Zhong Y, Zhang Z, Wang Y, Hu Y. Reduced CoNi₂S₄ nanosheets with enhanced conductivity for high-performance supercapacitors. Electrochimica Acta, 2018, 278: 33–41

39 Wang J, Zhao Y, Li G, Luo D, Liu J, Zhang Y, Wang X, Shui L, Chen Z. Aligned sulfur-deficient ZnS_1–x nanotube arrays as efficient catalyzer for high-performance lithium/sulfur batteries. Nano Energy, 2021, 84: 105891

40 Gao Y X, Xiong T Z, Li Y, Huang Y C, Li Y P, Balogun M S. A simple and scalable approach to remarkably boost the overall water splitting activity of stainless steel electrocatalysts. ACS Omega, 2019, 4(14): 16130–16138

41 Ma L, Liang J, Chen T, Liu Y, Li S, Fang G J. 3D CuCo₂S₄/NiCo₂S₄ core–shell composites as efficient bifunctional electrocatalyst electrodes for overall water splitting. Electrochimica Acta, 2019, 326: 135002

42 Li F, Xu R C, Li Y M, Liang F, Zhang D F, Fu W F, Lv X J. N-doped carbon coated NiCo₂S₄ hollow nanotube as bifunctional electrocatalyst for overall water splitting. Carbon, 2019, 145: 521–528

43 Gong Y, Lin Y, Yang Z, Wang J, Pan H, Xu Z, Liu Y. Crossed NiCo₂S₄ nanowires supported on nickel foam as a bifunctional catalyst for efficient overall water splitting. ChemistrySelect, 2019, 4(4): 1180–1187

44 Sivanantham A, Ganesan P, Shanmugam S. Hierarchical NiCo₂S₄ nanowire arrays supported on Ni foam: an efficient and durable bifunctional electrocatalyst for oxygen and hydrogen evolution reactions. Advanced Functional Materials, 2016, 26(26): 4661–4672

45 Dai W, Ren K, Zhu Y A, Pan Y, Yu J, Lu T. Flower-like CoNi₂S₄/Ni₃S₂ nanosheet clusters on nickel foam as bifunctional electrocatalyst for overall water splitting. Journal of Alloys and Compounds, 2020, 844: 156252

46 Ning Y, Ma D, Shen Y, Wang F, Zhang X. Constructing hierarchical mushroom-like bifunctional NiCo/NiCo₂S₄@NiCo/Ni foam electrocatalysts for efficient overall water splitting in alkaline media. Electrochimica Acta, 2018, 265: 19–31