Se-Rich MoSe₂ Nanosheets and Their Superior Electrocatalytic Performance for Hydrogen Evolution Reaction

Abstract

Two-dimensional MoSe2 has emerged as a promising electrocatalyst for the hydrogen evolution reaction (HER), although its catalytic activity needs to be further improved. Herein, we report Se-rich MoSe2 nanosheets synthesized using a hydrothermal reaction, displaying much enhanced HER performance at the Se/Mo ratio of 2.3. The transition from the 2H to the 1T′ phase occurred as Se/Mo exceeded 2. Structural analysis revealed the presence of Se adatoms as well as the formation of Se–Se bonding. Based on first-principles calculations, we propose two equally stable Se-rich structures. In the first one, excess Se atoms bridge two MoSe2 layers via the interlayer Se–Se bonds. In the second one, the Se atoms substitute for the Mo atoms, and extra Se atoms are added closest to the Mo-substituted Se. Calculation of Gibbs free energy along the reaction path indicates that the Se adatoms of the second model are the most active sites for HER.

Interfacial chemical bond and internal electric field modulated Z-scheme Sv-ZnIn2S4/MoSe2 photocatalyst for efficient hydrogen evolution

“…To fabricate the Z-scheme heterostructure, the primary premise is the matching band structure, in which the conduction band of one semiconductor should locate as close to the valence band of another semiconductor as possible. It is reported that the conduction band potential of MoSe 2 (about −0.45 eV 25 ) is lower than the conduction band of ZnIn 2 S 4 , but very close to its valence band (0.99 eV 9 ), which suggests that the photogenerated electrons in the conduction band of MoSe 2 are likely to recombine with the photogenerated holes in the valence band of ZnIn 2 S 4 following Z-scheme pathway. However, as known from the current literatures, MoSe 2 can only play the role of cocatalyst in ZnIn 2 S 4 /MoSe 2 instead of realizing Z-scheme charge transfer 26,27 .…”

Review on Synthesis and Catalytic Coupling Mechanism of Highly Active Electrocatalysts for Water Splitting

“…[ 19 ] To find suitable alternatives to Pt catalysts, researchers studied a variety of nonprecious metals catalysts. [ 20,21 ] Relevant researchers used cyclic voltammetry to sequence the catalytic activities of some non‐noble metals, and the measurement results were Ni > Mo > Co > W > Fe > Cu. [ 22 ]…”

Defect Engineering of Molybdenum-Based Materials for Electrocatalysis

“…Moreover, the doping of non-metallic atoms can change the crystalline phase of Mo-based materials, resulting in high catalytic activity. For example, Kwon and co-workers reported a non-stoichiometric Se-rich MoSe 2 synthesized by hydrothermal reaction [101]. When Se/Mo ratio exceeded two, the MoSe 2 changed from 2H to 1T' phase.…”