2D monolayer molybdenum(iv) telluride TMD: an efficient electrocatalyst for the hydrogen evolution reaction†

Abstract

An electrocatalyst is needed to efficiently lower the reaction barriers to produce hydrogen through the H₂ evolution reaction (HER). Recently, two-dimensional transition metal dichalcogenides (2D TMDs), such as the pure 2D monolayer MoTe₂, MoS₂, WS₂, etc. TMDs, have become attractive materials for the HER. Using the first principles-based hybrid density functional theory (DFT) method, we have computationally designed a pure 2D monolayer MoTe₂ TMD and examined its structural and electronic properties with electrocatalytic efficacy towards the HER. A non-periodic finite molecular cluster model Mo₁₀Te₂₁ system has been employed to explore the feasibility of both the Volmer–Heyrovsky (V–H) and Volmer–Tafel (V–T) reaction mechanisms for the HER. The solvent-phase calculations demonstrate that this material can effectively undergo either V–H or V–T reaction pathways. This conclusion is supported by our determination of low reaction barriers for the H*-migration, Heyrovsky, and Tafel transition states (TSs), which were found to be approximately 9.80, 12.55, and 5.29 kcal mol⁻¹, respectively. These results highlight the potential utility of 2D monolayer MoTe₂ TMD as a promising electrocatalyst for the HER. The unusual electrocatalytic activity of the pristine 2D monolayer MoTe₂ TMD is evidenced by its ability to significantly reduce reaction barriers, achieving impressive turnover frequency (TOF) values of 3.91 × 10³ and 8.22 × 10⁸ s⁻¹ during the Heyrovsky and Tafel reaction steps, respectively. Additionally, it demonstrates a remarkably low Tafel slope of 29.58 mV dec⁻¹. These outstanding performance metrics indicate that the pure 2D monolayer MoTe₂ TMD is a highly efficient electrocatalyst for the HER, surpassing the capabilities of traditional platinum group metal-based alternatives. Further exploration of its potential applications in electrocatalysis is warranted. The present work provides valuable insights into the atomic modulation of active sites for enhanced electrocatalytic performance towards the HER, paving the way for designing advanced non-noble metal-free electrocatalysts.