Revealing the Superior Electrocatalytic Performance of 2D Monolayer WSe₂ Transition Metal Dichalcogenide for Efficient H₂ Evolution Reaction

Abstract

has an adverse effect on human health as the emissions are very harmful for our society. Therefore, there is an increasing demand for the exploitation of inexpensive, earth-abundant, clean and renewable energy sources that can replace the overutilization of carbonbased fossil fuels and meet the global energy crisis deprived of the emission of any environmental and health pollutants. [1,2] Hydrogen has significant energy content, carries high energy density in its molecular form (H 2 ), and is present enormously in the form of water and other organic and inorganic compounds. Thus, it is considered as a promising and efficient green energy carrier. [3][4][5] In today's world, most commercially available H 2 fuel is manufactured by the steam reforming process. In this process, H 2 is produced along with carbon monoxide and carbon dioxide emissions like poisonous gases. The demerit of this process is that it has low energy efficiency for the conversion process and emits carbon-based unsafe byproducts. [6][7][8] An alternative way to produce clean and renewable H 2 is through the electrolysis of water with the passage of electricity through it. [7,9] Overall electrolysis of water completes with two half-cell reactions: hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode. H 2 evolution reaction (HER) requires an electrocatalyst to reduce the reaction barriers for the efficient production of H 2 . 2D transition metal dichalcogenides (2D TMDs) have emerged as a pinnacle group of materials for many potential applications, including HER. In this work, a pristine 2D monolayer WSe 2 TMD is computationally designed using the first principle-based hybrid density functional theory (DFT) to investigate its structural, electronic properties and the electrocatalytic performance for HER. The possible Volmer-Heyrovsky and Volmer-Tafel reaction mechanisms for HER at the W-edge of the active site of WSe 2 are studied by using a nonperiodic finite molecular cluster model W 10 Se 21 . The study shows that the pristine 2D monolayer WSe 2 follows either the Volmer-Heyrovsky or the Volmer-Tafel reaction mechanisms with a single-digit low reaction barrier about 6.11, 8.41 and 6.61 kcal mol −1 during the solvent phase calculations of H • -migration, Heyrovsky and Tafel transition (TS) states, respectively. The lower reaction barriers, high turnover frequency (TOF) ≈ 4.24 × 10 6 s −1 and 8.86 × 10 7 s −1 during the Heyrovsky and Tafel reaction steps and the low Tafel slope 29.58 mV dec −1 confirm that the pristine 2D monolayer WSe 2 might be a promising alternative to platinum group metals (PGM) based electrocatalyst.

Mechanistic understanding of efficient electrocatalytic hydrogen evolution reaction on a 2D monolayer WSSe Janus transition metal dichalcogenide

“…Furthermore, a vacuum slab of 500 Å is introduced in the Z direction to avoid the interaction between the two periodic units as implemented in CRYSTAL17. 47,67 Contribution related to the DFT exchange is assessed through the numerical integration of the unit cell volume. configuration leads to a molecular system with a periodicity of 3, which results in the achievement of a stabilized molecular cluster model having three edges without any unsatisfied valency.…”

“…Furthermore, a vacuum slab of 500 Å is introduced in the Z direction to avoid the interaction between the two periodic units as implemented in CRYSTAL17. 47,67…”

Platinum-adsorbed defective 2D monolayer boron nitride: a promising electrocatalyst for O2 reduction reaction

“…In addition to providing the reliable and attractive geometry of the monolayer 2D structure of the systems considered here, DFT-D (i.e., B3LYP-D3) is an extremely useful method because of the least effect of spin contamination on energy and density in the current calculations. [49][50][51][52] In each calculation, the electronic selfconsistency scale was set to 10 À7 a.u. Two-dimensional (2D) vacuum slabs were created for these materials so that the electrostatic potential could be considered in these computations, and the energies were reported in reference to the vacuum.…”

Atomic insight into the effects of precursor clusters on monolayer WSe2

“…In addition, WSe 2 has excellent catalytic performance. [30][31][32][33] Surface-supported clusters have been extensively studied, as the interaction between clusters and substrates plays an important role in the performance of catalysts and the growth of 2D Hongsheng Liu Hongsheng Liu obtained his PhD degree in condensed matter physics from the Dalian University of Technology in 2016. He is currently an associate professor in the Department of Physics at Dalian University of Technology.…”