Dual‐Native Vacancy Activated Basal Plane and Conductivity of MoSe₂ with High‐Efficiency Hydrogen Evolution Reaction

Abstract

Although transition metal dichalcogenide MoSe is recognized as one of the low-cost and efficient electrocatalysts for the hydrogen evolution reaction (HER), its thermodynamically stable basal plane and semiconducting property still hamper the electrocatalytic activity. Here, it is demonstrated that the basal plane and edges of 2H-MoSe toward HER can be activated by introducing dual-native vacancy. The first-principle calculations indicate that both the Se and Mo vacancies together activate the electrocatalytic sites in the basal plane and edges of MoSe with the optimal hydrogen adsorption free energy (ΔG ) of 0 eV. Experimentally, 2D MoSe nanosheet arrays with a large amount of dual-native vacancies are fabricated as a catalytic working electrode, which possesses an overpotential of 126 mV at a current density of 100 mV cm , a Tafel slope of 38 mV dec , and an excellent long-term durability. The findings pave a rational pathway to trigger the activity of inert MoSe toward HER and also can be extended to other layered dichalcogenide.

Transition Metal Selenides for Electrocatalytic Hydrogen Evolution Reaction

“…[32c,134] Several approaches have both merits, e. g., supporting materials on electrical conductivity carbon matrix, [20,54] metal heteroatom dopant, [56,135] dual-native vacancy fabricating. [63] Moreover, sev-…”

“…As vacancy can be tuned by changing growth temperature, both the amount of Mo and Se vacancies follow the order: nanosheets > nanoplates > microparticles. [63] Similarly, Wang et al synthesized the B-doped MoSe 2 nanosheets through placing the Se powder upstream of mixed material of B 2 O 3 and MoO 2 in a two-zone furnace, and ramping the Se and mixed material to 550°C and 920°C with a heating rate of 15°C min À 1 under mixed Ar (65 sccm) and H 2 (5 sccm), respectively. [64] With one-step CVD process, Zhou et al synthesized the NiSe 2 /Ni 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 hybrid foam.…”

“…The electrocatalytic sites in the inert basal plane and edges were activated, leading to optimal HER free energy (Δ G H* ) of ∼0 eV, increasing the amount of gap states/electrons near the Fermi level, and facilitating the electron transport in catalytic process. The results showed that the defected 2H‐MoSe 2 nanosheets presented an overpotential of 126 mV at a current density of 100 mV cm −2 , a Tafel slope of 38 mV dec −1 and good stability for 20 h I‐t test …”

Coupled Biphase (1T‐2H)‐MoSe2 on Mold Spore Carbon for Advanced Hydrogen Evolution Reaction

“…Electrochemical hydrogen evolution reaction (HER) is considered as one of the greenest technologies to produce hydrogen energy . It is well known that the HER efficiency and corresponding energy consumption are largely dependent on the physicochemical & electrochemical properties of electrocatalysts.…”

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energy. [1][2][3][4][5] It is well known that the HER efficiency and corresponding energy consumption are largely dependent on the physicochemical & electrochemical properties of electrocatalysts. Despite excellent HER performance of Pt-and Irbased noble metals, they still cannot be accepted by the market due to their compromised long-term stability, scarcity, and high cost.

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