Room-temperature ammonia sensing via Nb₂CT_x/SnS₂ nanocomposite sensor with enhanced selectivity

Abstract

The detection of ammonia (NH₃) is essential for environmental monitoring, industrial safety, and medical diagnosis. However, fluctuating environmental conditions and the limited stability of conventional sensing materials make it difficult to achieve highly selective, highly sensitive, and reliable NH₃ sensing at room temperature. To improve NH₃ selectivity, we investigated a dual-functionalized Nb₂CT_x/SnS₂ composite containing both amine and carboxyl groups. Combining the superior NH₃ adsorption capability of SnS₂ with the outstanding electrical conductivity and surface reactivity of the Nb₂CT_x MXene produces a composite that can be used as a highly sensitive and selective chemiresistive sensor. Experimental results revealed that this sensor had a low detection threshold of 10 ppm, along with fast response (32 s) and recovery (78 s) times at 100 ppm of NH₃ under ambient conditions. Moreover, under harsh environmental conditions such as exposure to interfering gases, high humidity, and temperature fluctuations, the incorporation of the amine and carboxyl groups significantly enhanced the structural integrity and selectivity of the sensor. In real-world applications, this sensor could exhibit exceptional selectivity for NH₃ against common interfering gases like formaldehyde, acetone, ethanol, trimethylamine, and CO₂. Overall, these results highlight that this material could be used to develop a high-performance NH₃ sensor with promising sensing characteristics under a wide range of environmental conditions.

Keywords

environmental monitoring / ammonia sensor / metal carbide / transition-metal dichalcogenide / composite

References

[1] Gong LK, Wang XW, Zhang DZ, Ma XD, Yu SJ. Flexible wearable humidity sensor based on cerium oxide/graphitic carbon nitride nanocomposite self-powered by motion-driven alternator and its application for human physiological detection. J. Mater. Chem. A, 2021, 9(9): 5619

[2] S. Wang, Y.D. Jiang, H.L. Tai, et al., An integrated flexible self-powered wearable respiration sensor, Nano Energy, 63(2019), art. No. 103829.

[3] Luo MY, Huang XP, Xiong DS, et al. . Fast response/recovery and sub-ppm ammonia gas sensors based on a novel V₂CT_x@MoS₂ composite. J. Mater. Chem. A, 2024, 12(20): 12225

[4] Zhang QP, Xie GZ, Duan MY, et al. . Zinc oxide nanorods for light-activated gas sensing and photocatalytic applications. ACS Appl. Nano Mater., 2023, 6(19): 17445

[5] C.X. Chen, G.Z. Xie, J. Dai, et al., Integrated core-shell structured smart textiles for active NO₂ concentration and pressure monitoring, Nano Energy, 116(2023), art. No. 108788.

[6] A.J. Mohan Reddy, M.S. Surendra Babu, and P. Nagaraju, ZnNi(NA) (NA = nicotinic acid) bimetallic mesoporous MOFs as a sensing platform for ethanol, formaldehyde and ammonia at room temperature, Solid State Sci., 125(2022), art. No. 106819.

[7] Singh S, Sattigeri RM, Kumar S, Jha PK, Sharma S. Superior room-temperature ammonia sensing using a hydrothermally synthesized MoS₂/SnO₂ composite. ACS Omega, 2021, 6(17): 11602

[8] M.H. Bai, R.C. Chen, X. Liu, et al., An effective strategy for synthesizing high-performance photocatalyst by recycling the graphite target wastes, J. Environ. Chem. Eng., 12(2024), No. 5, art. No. 113872.

[9] Zhou Y, Wang YH, Wang YJ, et al. . MXene Ti₃C₂T_x-derived nitrogen-functionalized heterophase TiO₂ homojunctions for room-temperature trace ammonia gas sensing. ACS Appl. Mater. Interfaces, 2021, 13(47): 56485

[10] C.M. Wu, Shrisha, K.G. Motora, G.Y. Chen, D.H. Kuo, and N.S. Gultom, Highly efficient MoS₂/Cs_xWO₃ nanocomposite hydrogen gas sensors, Front. Mater., 9(2022), art. No. 831725.

[11] H.Z. He, I. Ahmad Mir, B.J. Miao, et al., Synthesis of (Ti_yV_zCr_1−y−z)₃C₂T_x MXene for excellent electromagnetic wave absorption properties, J. Alloy. Compd., 1010(2025), art. No. 177521.

[12] Feng AH, Yu Y, Wang Y, et al. . Two-dimensional MXene Ti₃C₂ produced by exfoliation of Ti₃AlC₂. Mater. Des., 2017, 114: 161

[13] Yang ZJ, Liu A, Wang CL, et al. . Improvement of gas and humidity sensing properties of organ-like MXene by alkaline treatment. ACS Sens., 2019, 4(5): 1261

[14] Lee E, VahidMohammadi A, Prorok BC, Yoon YS, Beidaghi M, Kim DJ. Room temperature gas sensing of two-dimensional titanium carbide (MXene). ACS Appl. Mater. Interfaces, 2017, 9(42): 37184

[15] H.L. Tai, Z.H. Duan, Z.Z. He, et al., Enhanced ammonia response of Ti₃C₂T_x nanosheets supported by TiO₂ nanoparticles at room temperature, Sens. Actuators B, 298(2019), art. No. 126874.

[16] Lee SH, Eom W, Shin H, et al. . Room-temperature, highly durable Ti₃C₂T_x MXene/graphene hybrid fibers for NH₃ gas sensing. ACS Appl. Mater. Interfaces, 2020, 12(9): 10434

[17] Naguib M, Halim J, Lu J, et al. . New two-dimensional niobium and vanadium carbides as promising materials for Li-ion batteries. J. Am. Chem. Soc., 2013, 135(43): 15966

[18] D.S. Xiong, M.Y. Luo, Q. He, et al., Nb₂CT_x/MoSe₂ composites for a highly sensitive NH₃ gas sensor at room temperature, Talanta, 286(2025), art. No. 127446.

[19] J. Sun, W. Xiong, J.W. Zhang, Y. Zhang, and B. Xie, SnS₂ nanoparticle-based gas sensor with highly sensitive NO₂ detection at room temperature, Mater. Lett., 308(2022), art. No. 131214.

[20] Ranjith KS, Sonwal S, Mohammadi A, Raju GSR, Huh YS, Han YK. Engineering a surface functionalized Pt@SnS₂/Ti₃C₂T6_x MXene sensor with humidity tolerance and high sensitivity at room temperature for NH₃ detection. J. Mater. Chem. A, 2025, 13(4): 2950

[21] He TT, Sun SP, Huang BY, Li XG. MXene/SnS₂ heterojunction for detecting sub-ppm NH₃ at room temperature. ACSAppl. Mater. Interfaces, 2023, 15(3): 4194

[22] Xiong Y, Xu WW, Ding DG, et al. . Ultra-sensitive NH₃ sensor based on flower-shaped SnS₂ nanostructures with sub-ppm detection ability. J. Hazard. Mater., 2018, 341: 159

[23] Li MH, Gao XD, Zhang YF, Zheng YX, Lin ZH, Wei GF. Ammonia sensing properties of SnS₂/SnO₂ nanocomposite-based gas sensor by SnS₂ annealing. IEEE Sens. J., 2022, 22(23): 23456

[24] Huang YF, Jiao WC, Chu ZM, et al. . High sensitivity, humidity-independent, flexible NO₂ and NH₃ gas sensors based on SnS₂ hybrid functional graphene ink. ACS Appl. Mater. Interfaces, 2020, 12(1): 997

[25] C. Cui, R.H. Guo, H.Y. Xiao, et al., Bi₂WO₆/Nb₂CT_x MXene hybrid nanosheets with enhanced visible-light-driven photocatalytic activity for organic pollutants degradation, Appl. Surf. Sci., 505(2020), art. No. 144595.

[26] Choi M, William W, Hwang J, Yoon D, Kim J. A supercritical ethanol route for one-pot synthesis of tin sulfide–reduced graphene oxides and their anode performance for lithium ion batteries. J. Ind. Eng. Chem., 2018, 59: 160

[27] Din Babar ZU, Fatheema J, Arif N, et al. . Magnetic phase transition from paramagnetic in Nb₂AlC-MAX to superconductivity-like diamagnetic in Nb₂C-MXene: An experimental and computational analysis. RSC Adv., 2020, 10(43): 25669

[28] Zhu AQ, Qiao LL, Jia ZQ, et al. . C–S bond induced ultrafine SnS₂ dot/porous g-C₃N₄ sheet 0D/2D heterojunction: synthesis and photocatalytic mechanism investigation. Dalton Trans., 2017, 46(48): 17032

[29] M. Gandara, M.O. Martins, B. Šljukić, and E.S. Gonçalves, Synthesis of Nb-MXenes for electrocatalysis applications, Meet. Abstr, MA2023-02(2023), No. 54, art. No. 2608.

[30] Richard B, Niyas K, Mathew M, Rasheed PA. Lab on a syringe: Strategic design of 1T SnS₂/MXene embedded single-stranded carbon yarn for real-time stress biomarker detection. ACS Appl. Electron. Mater., 2024, 6(9): 6905

[31] Tan YB, Zhu ZY, Zhang XT, et al. . Nb₄C₃T_x (MXene) as a new stable catalyst for the hydrogen evolution reaction. Int. J. Hydrogen Energy, 2021, 46(2): 1955

[32] Rana PS. Structural, optical, electrical, and photocatalytic application of NiFe₂O₄@NiO nanocomposites for methylene blue dye. Ceram. Int., 2023, 49(9): 13520

[33] S. Bae, Y.G. Kang, M. Khazaei, et al., Electronic and magnetic properties of carbide MXenes—The role of electron correlations, Mater. Today Adv., 9(2021), art. No. 100118.

[34] Chang F, Wei ZX, Zhao ZY, Qi YF, Liu DG. 2D-2D heterostructured composites Bi₄O₅Br₂–SnS₂ with boosted photocatalytic NO_x abatement. J. Ind. Eng. Chem., 2023, 117: 265

[35] J.P. Xiao, J. Wen, J.B. Zhao, X.Z. Ma, H. Gao, and X.T. Zhang, A safe etching route to synthesize highly crystalline Nb₂CT_x MXene for high performance asymmetric supercapacitor applications, Electrochim. Acta, 337(2020), art. No. 135803.

[36] S. Velmurugan, S. Palanisamy, and T.C. Yang, Single-crystalline SnS₂ nano-hexagons based non-enzymatic electrochemical sensor for detection of carcinogenic nitrite in food samples, Sens. Actuators B, 316(2020), art. No. 128106.

[37] Wang HK, Lu X, Tucek J, et al. . Synthesis of polyvinylpyrrolidone-stabilized nonstoichiometric SnO₂ nanosheets with exposed {101} facets and Sn(II) self-doping as anode materials for Li-ion batteries. Electrochim. Acta, 2016, 211: 636

[38] S. Wang, Y.D. Jiang, B.H. Liu, et al., Ultrathin Nb₂CT_x nanosheets-supported polyaniline nanocomposite: Enabling ultrasensitive NH₃ detection, Sens. Actuators B, 343(2021), art. No. 130069.

[39] Q.P. Yang, S.J. Eder, A. Martini, and P.G. Grützmacher, Effect of surface termination on the balance between friction and failure of Ti₃C₂T_x MXenes, NPJ Mater. Degrad., 7(2023), art. No. 6.

[40] M. Doshi and E.P. Fahrenthold, Functionalized metallic carbon nanotube arrays for gas phase explosives detection, Comput. Theor. Chem., 1205(2021), art. No. 113460.

[41] V.T. Le, Y. Vasseghian, V.D. Doan, et al., Flexible and high-sensitivity sensor based on Ti₃C₂–MoS₂ MXene composite for the detection of toxic gases, Chemosphere, 291(2022), art. No. 133025.

[42] X. Xi, S.G. Yu, P. Li, J.Y. Zhang, T. Liang, and X. Ji, An ammonia sensor based on N-doped Ti₃C₃T/WS₂ with high stability for rapid fish freshness detection, Surf. Interfaces, 80(2026), art. No. 108359.

[43] Gasso S, Carrier J, Radu D, Lai CY. Novel gas sensing approach: ReS₂/Ti₃C₂T_x heterostructures for NH₃ detection in humid environments. ACS Sens., 2024, 9(9): 4788

[44] L. Lu, M.Y. Liu, Q.L. Sui, et al., MXene/MoS₂ nanosheet/polypyrrole for high-sensitivity detection of ammonia gas at room temperature, Mater. Today Commun., 35(2023), art. No. 106239.

RIGHTS & PERMISSIONS

University of Science and Technology Beijing