Issue

Vol. 19 (2027)

Biomimetic Gradient Porous Core–Shell Fibers with Enhanced Gas Sensing for CO-Temperature Dual-Mode Early Fire Warning

https://doi.org/10.1007/s40820-026-02292-8
Lele Huang
State Key Laboratory of New Textile Materials and Advanced Processing, Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing & Finishing, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China
Xingyu He
State Key Laboratory of New Textile Materials and Advanced Processing, Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing & Finishing, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China
Jianan Jiang
State Key Laboratory of New Textile Materials and Advanced Processing, Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing & Finishing, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China
Xiaoqian Li
State Key Laboratory of New Textile Materials and Advanced Processing, Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing & Finishing, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China
Mi Zhou
State Key Laboratory of New Textile Materials and Advanced Processing, Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing & Finishing, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China
Md Hasib Mia
Key Laboratory of High Performance Fibers & Products, Ministry of Education, College of Materials Science and Engineering, Donghua University, Shanghai 201620, People’s Republic of China
Min Hong
Centre for Future Materials, School of Science, Engineering and Digital Technologies, University of Southern Queensland, Springfield Central 4300, Australia
Hualing He
State Key Laboratory of New Textile Materials and Advanced Processing, Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing & Finishing, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China
Siqi Huo
Centre for Future Materials, School of Science, Engineering and Digital Technologies, University of Southern Queensland, Springfield Central 4300, Australia
Zhicai Yu
State Key Laboratory of New Textile Materials and Advanced Processing, Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing & Finishing, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China

Corresponding Author: Zhicai Yu

yuzhicaicai@163.com

Nano-Micro Letters, Vol. 19 (2027), Article Number: 17

Abstract

Early fire detection systems that are highly sensitive are essential for reducing the impact of fire disasters. However, their development still faces significant challenges due to the lack of capability for simultaneous monitoring of both temperature and gas. Herein, we propose a facile coaxial wet-spinning strategy to fabricate a dual-parameter fiber sensor capable of simultaneously detecting carbon monoxide (CO) and temperature for early combustion warning. The resulting core–sheath structured fiber consists of a CO sensing sheath made of SnO2/In2O3 heterojunction/aramid nanofiber (ANF)/silver nanowire composite with biomimetic gradient pores, an ANF isolation layer, and a temperature sensing core composed of MXene. The gradient porous sheath constructed by gradient-induced phase separation technology exhibits gradually decreasing pore sizes from outer (> 10 μm) to inner (< 3 μm) regions. This structure demonstrates a significant enhancement in the fiber sensor’s sensitivity to CO, achieving a 15% higher response compared to non-gradient porous structures (ΔR/R0 = 0.95%/ppm; detection limit of 10 ppm), with the response time reduced to 19.28 s, surpassing the response speed of most fire-warning fibers. Additionally, this fiber sensor can rapidly monitor abnormal temperature increases, enabling flame alarm functionality within 3 s. It also achieves precise real-time temperature detection within the range of 50–300 °C, exhibiting high sensitivity (20.6 μV K−1) and a strong linear correlation (R2 = 0.99). This work highlights the significant potential of gradient pore in enhancing CO sensing and offers a novel perspective for the design of ultrafast early fire-warning fiber sensors.


Highlights:
1 A biomimetic gradient porous core–shell fiber with enhanced gas-sensing capabilities for CO-temperature early fire warning is fabricated via a coaxial wet-spinning technology.
2 The gradient porous sheath with SnO2/In2O3 heterojunction endows enhanced CO gas-sensing performance with high sensitivity, low detection limit and improves the CO respond of by 15%.
3 The CO-temperature dual-mode sensing fiber integrated with a wireless early fire-warning system achieves a rapid respond to fire in ~3 s and detects 10 ppm CO gas within 19 s.

Keywords

Early fire warning Bimodal sensing fiber Gradient porous Coaxial wet spinning CO-temperature detection
Huang, Lele, Xingyu He, Jianan Jiang, Xiaoqian Li, Mi Zhou, Md Hasib Mia, Min Hong, Hualing He, Siqi Huo, and Zhicai Yu. 2026. “Biomimetic Gradient Porous Core–Shell Fibers With Enhanced Gas Sensing for CO-Temperature Dual-Mode Early Fire Warning”. Nano-Micro Letters 19 (August):17. https://doi.org/10.1007/s40820-026-02292-8.
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References
  1. G. Lasslop, S. Hantson, S.P. Harrison, D. Bachelet, C. Burton et al., Global ecosystems and fire: Multi-model assessment of fire-induced tree-cover and carbon storage reduction. Glob. Change Biol. 26(9), 5027–5041 (2020). https://doi.org/10.1111/gcb.15160
  2. S. Zhang, Y. Song, Q. Dong, H. Yang, L. Shi, Developing an indicator system for urban fire risk assessment. Fire Saf. J. 158, 104536 (2025). https://doi.org/10.1016/j.firesaf.2025.104536
  3. C. Maluk, M. Woodrow, J.L. Torero, The potential of integrating fire safety in modern building design. Fire Saf. J. 88, 104–112 (2017). https://doi.org/10.1016/j.firesaf.2016.12.006
  4. L.-Y. Lv, C.-F. Cao, Y.-X. Qu, G.-D. Zhang, L. Zhao et al., Smart fire-warning materials and sensors: Design principle, performances, and applications. Mater. Sci. Eng. R. Rep. 150, 100690 (2022). https://doi.org/10.1016/j.mser.2022.100690
  5. X. He, Y. Feng, F. Xu, F.-F. Chen, Y. Yu, Smart fire alarm systems for rapid early fire warning: Advances and challenges. Chem. Eng. J. 450, 137927 (2022). https://doi.org/10.1016/j.cej.2022.137927
  6. W.W. Jones, Implementing high reliability fire detection in the residential setting. Fire Technol. 48(2), 233–254 (2012). https://doi.org/10.1007/s10694-010-0211-8
  7. H. Xu, Y. Li, N.-J. Huang, Z.-R. Yu, P.-H. Wang et al., Temperature-triggered sensitive resistance transition of graphene oxide wide-ribbons wrapped sponge for fire ultrafast detecting and early warning. J. Hazard. Mater. 363, 286–294 (2019). https://doi.org/10.1016/j.jhazmat.2018.09.082
  8. C.-F. Cao, W.-J. Liu, H. Xu, K.-X. Yu, L.-X. Gong et al., Temperature-induced resistance transition behaviors of melamine sponge composites wrapped with different graphene oxide derivatives. J. Mater. Sci. Technol. 85, 194–204 (2021). https://doi.org/10.1016/j.jmst.2020.12.073
  9. Y. Zhao, J. Wu, P. Shen, J. Li, W. Xin et al., A review of wearable flexible sensors for sports: from materials to applications. Int. J. Smart Nano Mater. 16(4), 695–725 (2025). https://doi.org/10.1080/19475411.2025.2552803
  10. K. Lee, Y.-S. Shim, Y.G. Song, S.D. Han, Y.-S. Lee et al., Highly sensitive sensors based on metal-oxide nanocolumns for fire detection. Sensors 17(2), 303 (2017). https://doi.org/10.3390/s17020303
  11. Y. Cai, Z. Zheng, Z. Zhong, Y. Zhang, T. Huang et al., Heterointerface-functionalized photoelectric response of metal-oxide Schottky photodiode for intelligent fire detection. Adv. Sci. 13(9), e19318 (2026). https://doi.org/10.1002/advs.202519318
  12. M. Zhou, L. Huang, Y. Wan, Q. Jiang, X. Qu et al., Integrated temperature–NH3 multiplex sensing fibers enabled by programmable assembly of MXene@MoS2 heterojunction and p/n-type thermoelectric core for firefighting clothing. Adv. Fiber Mater. 7(6), 2013–2031 (2025). https://doi.org/10.1007/s42765-025-00599-6
  13. H. Zheng, X. Han, Q. Wei, C. Zheng, C. Huang et al., Biomass-based flexible fire warning sensor with excellent flame retardancy and sensitivity. Chem. Eng. J. 437, 135412 (2022). https://doi.org/10.1016/j.cej.2022.135412
  14. C. Jiang, J. Chen, X. Lai, H. Li, X. Zeng et al., Mechanically robust and multifunctional polyimide/MXene composite aerogel for smart fire protection. Chem. Eng. J. 434, 134630 (2022). https://doi.org/10.1016/j.cej.2022.134630
  15. Y. Hu, G. Rein, Development of gas signatures of smouldering peat wildfire from emission factors. Int. J. Wildland Fire 31(11), 1014–1032 (2022). https://doi.org/10.1071/wf21093
  16. B. Wang, X. Lai, H. Li, C. Jiang, J. Gao et al., Multifunctional MXene/chitosan-coated cotton fabric for intelligent fire protection. ACS Appl. Mater. Interfaces 13(19), 23020–23029 (2021). https://doi.org/10.1021/acsami.1c05222
  17. H. Wang, C. Fan, J. Li, Y. Zhang, X. Sun et al., Dynamic characteristics of near-surface spontaneous combustion gas flux and its response to meteorological and soil factors in coal fire area. Environ. Res. 217, 114817 (2023). https://doi.org/10.1016/j.envres.2022.114817
  18. W. Zhai, X. Li, Q. Xia, P. Zhan, J. Xu et al., Multi-functional and flexible helical fiber sensor for micro-deformation detection, temperature sensing and ammonia gas monitoring. Compos. Part B Eng. 211, 108621 (2021). https://doi.org/10.1016/j.compositesb.2021.108621
  19. J. Liu, Y. Yang, G. Chen, H. Sun, X. Xie et al., Stretchable and high-performance fibrous sensors based on ionic capacitive sensing for wearable healthcare monitoring. Adv. Sci. 12(1), 2412859 (2025). https://doi.org/10.1002/advs.202412859
  20. Y. Wang, X. Liu, C. Li, W. Wang, D. Guo et al., Scalable topological-entanglement conductive coaxial fibers with superior durability for wearable strain sensing and triboelectric fabric. J. Mater. Sci. Technol. 233, 154–165 (2025). https://doi.org/10.1016/j.jmst.2024.12.096
  21. F. Meng, J. Wen, J. Ma, Y. Tian, A dual-functional sensor based on PEDOT: PSS for sensing temperature and ammonia fabricated by electrohydrodynamic printing. J. Mater. Sci. Mater. Electron. 35(27), 1834 (2024). https://doi.org/10.1007/s10854-024-13555-8
  22. D. Xu, C. Gao, C. Ge, Y. Liu, L. Yang et al., Integrated firefighting textile with temperature and pressure monitoring for personal defense. ACS Sens. 9(5), 2575–2584 (2024). https://doi.org/10.1021/acssensors.4c00288
  23. R. Li, X.-L. Shi, J. Zhu, Q. Deng, W. Ou et al., Cu3SbSe3-alloying-induced high thermoelectric performance and mechanical robustness in Bi2Te3-based thermoelectric materials. Adv. Sci. 12(42), e12417 (2025). https://doi.org/10.1002/advs.202512417
  24. X. Yang, Y. Shi, K. Xie, S. Fang, Y. Zhang et al., Cocrystallization enabled spatial self-confinement approach to synthesize crystalline porous metal oxide nanosheets for gas sensing. Angew. Chem. Int. Ed. 61(37), e202207816 (2022). https://doi.org/10.1002/anie.202207816
  25. Z. Yu, L. Huang, M. Zhou, J. Xu, J. Ma et al., Dual-mode core–shell structured early fire warning sensing fiber with selective CO and temperature detection. Chem. Eng. J. 512, 162586 (2025). https://doi.org/10.1016/j.cej.2025.162586
  26. H. Yu, D. Sun, W. Dong, R. Cao, Y. Zhou et al., All-In-one flexible thermoelectric yarns for integrated energy harvesting, adaptive personal thermal management, and self-powered sensing. Adv. Funct. Mater. 36(28), e25233 (2026). https://doi.org/10.1002/adfm.202525233
  27. H. He, Y. Qin, J. Liu, Y. Wang, J. Wang et al., A wearable self-powered fire warning e-textile enabled by aramid nanofibers/MXene/silver nanowires aerogel fiber for fire protection used in firefighting clothing. Chem. Eng. J. 460, 141661 (2023). https://doi.org/10.1016/j.cej.2023.141661
  28. L. Deng, Y. Zhang, H. Xu, W. Zhang, S. Hui et al., Wearable fabrics against ultra-broadband electromagnetic interference. Matter 9(5), 102697 (2026). https://doi.org/10.1016/j.matt.2026.102697
  29. X. Jiang, L. Deng, Y. Zhang, Y. Bao, M. Guo et al., Ultrasound-responsive BTO@MSN-Cu/chitosan coatings on titanium implants with synergistic antibacterial and angiogenic effects. Colloids Surf. B Biointerfaces 265, 115759 (2026). https://doi.org/10.1016/j.colsurfb.2026.115759
  30. J. Wen, L. Deng, H. Shen, Q. Chen, H. Wu, Plasma-assisted bipolarity carrier modulation in TMDs to accelerate dipole polarization for enhanced electromagnetic attenuation. Adv. Funct. Mater. 36(11), e19086 (2026). https://doi.org/10.1002/adfm.202519086
  31. Q. Liu, A. Zhao, X. He, Q. Li, J. Sun et al., Full-temperature all-solid-state Ti3C2Tx/aramid fiber supercapacitor with optimal balance of capacitive performance and flexibility. Adv. Funct. Mater. 31(22), 2010944 (2021). https://doi.org/10.1002/adfm.202010944
  32. C. Jiang, C. Wu, X. Li, Y. Yao, L. Lan et al., All-electrospun flexible triboelectric nanogenerator based on metallic MXene nanosheets. Nano Energy 59, 268–276 (2019). https://doi.org/10.1016/j.nanoen.2019.02.052
  33. H. He, Q. Jiang, Y. Wan, M.H. Mia, X. Qu et al., Biological skin-inspired damage warning and self-healing thermoelectric aerogel fiber via coaxial wet spinning for wearable temperature sensing. J. Mater. Sci. Technol. 250, 257–271 (2026). https://doi.org/10.1016/j.jmst.2025.06.038
  34. Z. Yu, X. Qu, M. Zhou, M.H. Mia, L. Hou et al., Integrated core-shell structured polyimide thermoelectric fiber with latent light-driven damage detection and self-driven temperature sensing performance. Chem. Eng. J. 515, 163622 (2025). https://doi.org/10.1016/j.cej.2025.163622
  35. W. Eom, H. Shin, R.B. Ambade, S.H. Lee, K.H. Lee et al., Large-scale wet-spinning of highly electroconductive MXene fibers. Nat. Commun. 11(1), 2825 (2020). https://doi.org/10.1038/s41467-020-16671-1
  36. X. Li, X. He, M. Zhou, Z. Yu, Q. Zheng et al., Ultrarobust alginate-based temperature sensing fiber across subzero to above zero self-healing performance enabled by polyphenol-nanosphere engineered multiple dynamic bonds. Carbohydr. Polym. 385, 125395 (2026). https://doi.org/10.1016/j.carbpol.2026.125395
  37. L.-X. Liu, W. Chen, H.-B. Zhang, L. Ye, Z. Wang et al., Super-tough and environmentally stable aramid. Nanofiber@MXene coaxial fibers with outstanding electromagnetic interference shielding efficiency. Nano-Micro Lett. 14(1), 111 (2022). https://doi.org/10.1007/s40820-022-00853-1
  38. Y. Li, X. Song, L. Li, W. Wu, K. Tao et al., Low concentration CO gas sensor constructed from MoS2 nanosheets dispersed SnO2 nanops at room temperature under UV light. Ceram. Int. 49(7), 10249–10254 (2023). https://doi.org/10.1016/j.ceramint.2022.11.204
  39. J.T. McCue, J.Y. Ying, SnO2−In2O3 nanocomposites as semiconductor gas sensors for CO and NOx detection. Chem. Mater. 19(5), 1009–1015 (2007). https://doi.org/10.1021/cm0617283
  40. K. Wan, D. Wang, F. Wang, H. Li, J. Xu et al., Hierarchical In2O3@SnO2 core-shell nanofiber for high efficiency formaldehyde detection. ACS Appl. Mater. Interfaces 11(48), 45214–45225 (2019). https://doi.org/10.1021/acsami.9b16599
  41. S. Cai, Y. Ju, Y. Wang, X. Li, T. Guo et al., Fast-response oxygen optical fiber sensor based on PEA(2) SnI(4) perovskite with extremely low limit of detection. Adv. Sci. 9(8), 2104708 (2022). https://doi.org/10.1002/advs.202104708
  42. Z. Yu, Y. Wan, M. Zhou, M.H. Mia, S. Huo et al., Muscle-inspired anisotropic aramid nanofibers aerogel exhibiting high-efficiency thermoelectric conversion and precise temperature monitoring for firefighting clothing. Nano-Micro Lett. 17(1), 214 (2025). https://doi.org/10.1007/s40820-025-01728-x
  43. X. Fu, L. Si, Z. Zhang, T. Yang, Q. Feng et al., Gradient all-nanostructured aerogel fibers for enhanced thermal insulation and mechanical properties. Nat. Commun. 16, 2357 (2025). https://doi.org/10.1038/s41467-025-57646-4
  44. Y. Bai, W. Zhang, Z. Zhang, X. Zhang, X. Wang et al., From nature to engineering: coupling bioinspired gradient pores and composite synergy in negative Poisson aramid/cellulose aerogels for oil-water separation and thermal insulation. Chem. Eng. J. 522, 167139 (2025). https://doi.org/10.1016/j.cej.2025.167139
  45. J. Peng, F. Ge, W. Han, T. Wu, J. Tang et al., MXene-based thermoelectric fabric integrated with temperature and strain sensing for health monitoring. J. Mater. Sci. Technol. 212, 272–280 (2025). https://doi.org/10.1016/j.jmst.2024.06.011
  46. F.-L. Gao, J. Liu, X.-P. Li, Q. Ma, T. Zhang et al., Ti3C2Tx MXene-based multifunctional tactile sensors for precisely detecting and distinguishing temperature and pressure stimuli. ACS Nano 17(16), 16036–16047 (2023). https://doi.org/10.1021/acsnano.3c04650
  47. Q. Wang, L. Zhou, S. Li, X. Chang, X. Liu et al., Atomic layer deposition of SnO2 on In2O3 enables ultrasensitive NO2 detection at room temperature and DFT mechanism research. Appl. Surf. Sci. 640, 158410 (2023). https://doi.org/10.1016/j.apsusc.2023.158410
  48. H. Du, P. Yao, Y. Sun, J. Wang, H. Wang et al., Electrospinning hetero-nanofibers In2O3/SnO2 of homotype heterojunction with high gas sensing activity. Sensors 17(8), 1822 (2017). https://doi.org/10.3390/s17081822
  49. N. Singh, C. Yan, P.S. Lee, Room temperature CO gas sensing using Zn-doped In2O3 single nanowire field effect transistors. Sens. Actuat. B Chem. 150(1), 19–24 (2010). https://doi.org/10.1016/j.snb.2010.07.051
  50. K. Wang, T. Zhao, G. Lian, Q. Yu, C. Luan et al., Room temperature CO sensor fabricated from Pt-loaded SnO2 porous nanosolid. Sens. Actuat. B Chem. 184, 33–39 (2013). https://doi.org/10.1016/j.snb.2013.04.054
  51. H.-D. Zhang, Y.-Z. Long, Z.-J. Li, B. Sun, Fabrication of comb-like ZnO nanostructures for room-temperature CO gas sensing application. Vacuum 101, 113–117 (2014). https://doi.org/10.1016/j.vacuum.2013.07.046
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