Chalcogen Vacancy Engineering in 1T-TiS₂, 1T-TiSe₂ and 1T-TiTe₂ Monolayers for Enhanced HER Activity: A DFT Study
DOI:
https://doi.org/10.56919/usci.2652.029Keywords:
Hydrogen evolution reaction, Titanium dichalcogenides, Vacancy engineering, Density functional theory, Electrocatalysis, Green hydrogenAbstract
Electrocatalytic water splitting offers a sustainable pathway for green hydrogen production, yet its widespread adoption requires low-cost and earth-abundant alternatives to platinum-group metal catalysts. Herein, we present a systematic density functional theory (DFT) study of chalcogen vacancy engineering on the catalytic performance of 1T-TiX₂ (X = S, Se, Te) monolayers in hydrogen evolution reaction (HER). Our calculations reveal that pristine 1T-TiX₂ surfaces exhibit poor hydrogen adsorption, with 1T-TiS₂ lying on the strong-binding side, while 1T-TiSe₂ and 1T-TiTe₂ reside on the weak-binding side of the volcano curve, explaining their unfavourable catalytic activity. The introduction of single chalcogen vacancies dramatically shifts all systems toward the volcano apex, with defective 1T-TiS₂ achieving a near-thermoneutral Gibbs free energy of hydrogen adsorption (ΔGH*) of -0.08 eV, thermodynamically comparable to the benchmark Pt (111) value (-0.09 eV). This promising computational result requires experimental validation. Defect formation energies are positive for all systems (3.53 eV, 2.73 eV, and 2.12 eV for S, Se, and Te vacancies, respectively), indicating thermodynamic stability of the vacancy configurations under computational chemical-potential conditions. Electronic structure analysis further demonstrates that vacancy-induced metallization generates prominent states at the Fermi level, thereby enhancing charge-transfer kinetics. Notably, 1T-TiS₂ undergoes a semimetallic to metallic transition upon S-vacancy creation, whereas 1T-TiSe₂ and 1T-TiTe₂ show moderate electronic enhancement. This work establishes chalcogen-vacancy engineering as a universal strategy for activating the 1T-TiX₂ basal planes. It identifies defective 1T-TiS₂ as the most promising, cost-effective, and non-precious HER catalyst within the 1T-TiX₂ family, providing design principles for next-generation sustainable hydrogen production technologies.
References
Alhassan, S. S., Abdulsalam, M., & Tanimu, A. (2025). Application of transition metals dichalcogenides in electrocatalytic splitting of water for hydrogen production: A review. Nigerian Journal of Physics, 34, 44. DOI: https://doi.org/10.62292/10.62292/njp.v34i2.2025.366
Alhassan, S. S., Abdulsalam, M., Tanimu, A., & Bagudo, I. M. (2025). Role of Van der Waals correction on the catalytic performance of 1T-TiS₂ electrocatalyst. African Scientific Reports, 4, 356. DOI: https://doi.org/10.46481/asr.2025.4.3.356
Buslaps, T., Johnson, R. L., & Jungk, G. (1993). Spectroscopic ellipsometry on 1T-TiSe₂. Thin Solid Films, 234, 549-552. DOI: https://doi.org/10.1016/0040-6090(93)90329-N
Chen, P., Pai, W. W., Chan, Y.-H., Takayama, A., Xu, C.-Z., Chou, M. Y., Mo, S.-K., Fedorov, A.-V., & Chiang, T.-C. (2017). Emergence of charge density waves and a pseudogap in single-layer TiTe₂. Nature Communications, 8, 516. DOI: https://doi.org/10.1038/s41467-017-00641-1
Chhowalla, M., Liu, Z., & Zhang, H. (2015). Two-dimensional transition metal dichalcogenide (TMD) nanosheets. Chemical Society Reviews, 44, 2584-2606. DOI: https://doi.org/10.1039/C5CS90037A
Das, T., Chakraborty, S., Ahuja, R., & Das, G. P. (2019). TiS₂ monolayer as an emerging ultrathin bifunctional catalyst: Influence of defects and functionalization. ChemPhysChem, 20, 608-615. DOI: https://doi.org/10.1002/cphc.201801031
Deng, C., He, R., Shen, W., Li, M., & Zhang, T. (2019). A single-atom catalyst of cobalt supported on a defective two-dimensional boron nitride material as a promising electrocatalyst for the oxygen reduction reaction: A DFT study. Physical Chemistry Chemical Physics, 21, 6900-6907. DOI: https://doi.org/10.1039/C9CP00452A
Fu, Q., et al. (2020). 2D transition metal dichalcogenides: Design, modulation, and challenges in electrocatalysis. Advanced Materials, 32, 1907818. DOI: https://doi.org/10.1002/adma.201907818
Geng, S., Yang, W., Liu, Y., & Yu, Y. (2020). Engineering sulfur vacancies in basal plane of MoS₂ for enhanced hydrogen evolution reaction. Journal of Catalysis, 391, 91-97. DOI: https://doi.org/10.1016/j.jcat.2020.05.042
Giannozzi, P., et al. (2009). Quantum ESPRESSO: A modular and open-source software project for quantum simulations of materials. Journal of Physics: Condensed Matter, 21, 395502. DOI: https://doi.org/10.1088/0953-8984/21/39/395502
Grimme, S., Antony, J., Ehrlich, S., & Krieg, H. (2010). A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. Journal of Chemical Physics, 132, 154104. DOI: https://doi.org/10.1063/1.3382344
Guesmi, I., Bouammali, M. A., Malki, S., Darhi, Z., Challioui, A., & El Farh, L. (2023). Theoretical investigation of optoelectronics properties of titanium dichalcogenides materials TiX₂ (X = S, Se, Te) using Quantum ESPRESSO. Materials Science Forum, 1095, 21-35. DOI: https://doi.org/10.4028/p-erZ4kn
Huang, H., Hu, G., Hu, C., & Fan, X. (2022). Enhanced hydrogen evolution reactivity of T′-phase tungsten dichalcogenides (WS₂, WSe₂, and WTe₂) materials: A DFT study. International Journal of Molecular Sciences, 23, 11727. DOI: https://doi.org/10.3390/ijms231911727
Iqrar, U., Alarfaji, S. S., Nabi, G., & Khan, M. I. (2025). Light-metal decorated titanium disulfide as an efficient hydrogen storage material: A DFT study. International Journal of Hydrogen Energy, 169, 151115. DOI: https://doi.org/10.1016/j.ijhydene.2025.151115
Jaramillo, T. F., Jørgensen, K. P., Bonde, J., Nielsen, J. H., Horch, S., & Chorkendorff, I. (2007). Identification of active edge sites for electrochemical H₂ evolution from MoS₂ nanocatalysts. Science, 317, 100-102. DOI: https://doi.org/10.1126/science.1141483
Kazemi, S. A., Yengejeh, S. I., Ogunkunle, S. A., Wen, Z. L., Liew, A. W. C., & Wang, Y. (2023). Vacancy impacts on electronic and mechanical properties of MX₂ (M = Mo, W and X = S, Se) monolayers. RSC Advances, 13, 6498-6506. DOI: https://doi.org/10.1039/D3RA00205E
Man, I. C., Su, H. Y., Calle-Vallejo, F., Hansen, H. A., Martinez, J. I., Inoglu, N. G., Kitchin, J., Jaramillo, T. F., Nørskov, J. K., & Rossmeisl, J. (2011). Universality in oxygen evolution electrocatalysis on oxide surfaces. ChemCatChem, 3, 1159-1165. DOI: https://doi.org/10.1002/cctc.201000397
Mannix, A. J., Zhang, Z., Guisinger, N. P., Yakobson, B. I., & Hersam, M. C. (2018). Borophene as a prototype for synthetic 2D materials development. Nature Nanotechnology, 13, 444-450. DOI: https://doi.org/10.1038/s41565-018-0157-4
Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13, 5188-5192. DOI: https://doi.org/10.1103/PhysRevB.13.5188
Nørskov, J. K., Bligaard, T., Logadottir, A., Kitchin, J., Chen, J. G., Pandelov, S., & Stimming, U. (2005). Trends in the exchange current for hydrogen evolution. Journal of the Electrochemical Society, 152, J23-J26. DOI: https://doi.org/10.1149/1.1856988
Ogunkunle, S. A., Bouzid, A., Hinsch, J. J., Allen, O. J., White, J. J., Bernard, S., Wu, Z., Zhu, Y., & Wang, Y. (2024). Defect engineering of 1T′ MX₂ (M = Mo, W and X = S, Se) transition metal dichalcogenide-based electrocatalyst for alkaline hydrogen evolution reaction. Journal of Physics: Condensed Matter, 36, 145002. DOI: https://doi.org/10.1088/1361-648X/ad19a4
Pan, H., Feng, Y. P., & Lin, J. (2007). Hydrogen adsorption by tungsten carbide nanotube. Applied Physics Letters, 90, 223104. DOI: https://doi.org/10.1063/1.2744479
Paliwal, U., Tanwar, P., & Joshi, K. B. (2024). Structural, electronic and thermoelectric properties of monolayer TiSe₂. Journal of Molecular Modeling, 30, 80. DOI: https://doi.org/10.1007/s00894-024-05865-9
Perdew, J. P., Burke, K., & Ernzerhof, M. (1996). Generalized gradient approximation made simple. Physical Review Letters, 77, 3865-3868. DOI: https://doi.org/10.1103/PhysRevLett.77.3865
Qing, Z., Wenzhou, C., Hua, C., Zhouguang, L., & Hui, P. (2019). WS₂ nanosheets with highly-enhanced electrochemical activity by facile control of sulfur vacancies. ChemCatChem, 11, 4219-4225.
Ran, N., Sun, B., Qiu, W., Song, E., Chen, T., & Liu, J. (2021). Identifying metallic transition-metal dichalcogenides for hydrogen evolution through multilevel high-throughput calculations and machine learning. Journal of Physical Chemistry Letters, 12, 2102-2111. DOI: https://doi.org/10.1021/acs.jpclett.0c03839
Seh, Z. W., Kibsgaard, J., Dickens, C. F., Chorkendorff, I., Nørskov, J. K., & Jaramillo, T. F. (2017). Combining theory and experiment in electrocatalysis: Insights into materials design. Science, 355, eaad4998. DOI: https://doi.org/10.1126/science.aad4998
Stamenkovic, V. R., Strmcnik, D., Lopes, P. P., & Markovic, N. M. (2017). Energy and fuels from electrochemical interfaces. Nature Materials, 16, 57-69. DOI: https://doi.org/10.1038/nmat4738
Sukanya, R., da Silva Alves, D. C., & Breslin, C. B. (2022). Recent developments in the applications of 2D transition metal dichalcogenides as electrocatalysts in the generation of hydrogen for renewable energy conversion. Journal of the Electrochemical Society, 169, 064504. DOI: https://doi.org/10.1149/1945-7111/ac7172
Tanwar, P., Paliwal, U., Joshi, K. B., & Kumar, J. (2023). First-principles study of structural, electronic and vibrational properties of bulk and monolayer TiS₂. Journal of Physics and Chemistry of Solids, 179, 111382. DOI: https://doi.org/10.1016/j.jpcs.2023.111382
Vojvodic, A., Nørskov, J. K., & Abild-Pedersen, F. (2014). Electronic structure effects in transition metal surface chemistry. Topics in Catalysis, 57, 25-32. DOI: https://doi.org/10.1007/s11244-013-0159-2
Wang, H., et al. (2013). Electrochemical tuning of vertically aligned MoS₂ nanofilms and its application in improving hydrogen evolution reaction. Proceedings of the National Academy of Sciences, 110, 19701-19706. DOI: https://doi.org/10.1073/pnas.1316792110
Wang, J., Liu, Y.-P., Zhang, H., Huang, D.-J., & Chu, K. (2019). Ambient electrocatalytic nitrogen reduction on a MoO₂/graphene hybrid: Experimental and DFT studies. Catalysis Science and Technology, 9, 4248-4254. DOI: https://doi.org/10.1039/C9CY00907H
Wu, J., Zhong, W., Yang, C., Xu, W., Zhao, R., Xiang, H., Zhang, Q., Li, X., & Yang, N. (2022). Sulfur-vacancy rich nonstoichiometric TiS₂-x/NiS heterostructures for superior universal hydrogen evolution. Applied Catalysis B: Environmental, 310, 121332. DOI: https://doi.org/10.1016/j.apcatb.2022.121332
Wu, Q., Chen, Y., Hao, X., Zhu, T., Cao, Y., & Wang, W. (2021). Insight into the anchoring effect of two-dimensional TiX₂ (X = S, Se, Te) materials for lithium-sulfur batteries: A DFT study. Journal of the Electrochemical Society, 168, 120516. DOI: https://doi.org/10.1149/1945-7111/ac3ab2
Xu, H. X., Cheng, D. J., Cao, D. P., & Zeng, X. C. (2018). A universal principle for a rational design of single-atom electrocatalysts. Nature Catalysis, 1, 339-348. DOI: https://doi.org/10.1038/s41929-018-0063-z
Yin, Y., et al. (2016). Contributions of phase, sulfur vacancies, and edges to the hydrogen evolution reaction catalytic activity of porous molybdenum disulfide nanosheets. Journal of the American Chemical Society, 138, 7965-7972. DOI: https://doi.org/10.1021/jacs.6b03714
Zeng, Z., Yin, Z., Huang, X., Li, H., He, Q., Lu, G., Boey, F., & Zhang, H. (2011). Single-layer semiconducting nanosheets: High-yield preparation and device fabrication. Angewandte Chemie International Edition, 50, 11093-11097. DOI: https://doi.org/10.1002/anie.201106004
Zhao, B., Shen, D., Zhang, Z., Lu, P., Hossain, M., Li, J., Li, B., & Duan, X. (2021). 2D metallic transition-metal dichalcogenides: Structures, synthesis, properties, and applications. Advanced Functional Materials, 31, 2105132. DOI: https://doi.org/10.1002/adfm.202105132
Zhao, W.-M., et al. (2022). Moiré enhanced charge density wave state in twisted 1T-TiTe₂/1T-TiSe₂ heterostructures. Nature Materials, 21, 284-290. DOI: https://doi.org/10.1038/s41563-021-01167-0
Zhou, W., Zou, X., Najmaei, S., Liu, Z., Shi, Y., Kong, J., Lou, J., Ajayan, P. M., Yakobson, B. I., & Idrobo, J.-C. (2013). Nano Letters, 13, 2615-2622. DOI: https://doi.org/10.1021/nl4007479
Zhu, J., Hu, L., Zhao, P., Lee, L. Y. S., & Wong, K. Y. (2020). Recent advances in electrocatalytic hydrogen evolution using nanoparticles. Chemical Reviews, 120, 851-918. DOI: https://doi.org/10.1021/acs.chemrev.9b00248
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