Unravelling the Origin of Enhanced Electrochemical Performance in CoSe₂−MoSe₂ Interfaces

Abstract

Defect and interface engineering have been shown as effective strategies towards sustainable hydrogen production, but detailed descriptions of the origin of performance enhancements is not established. Here, we synthesize a model heterostructure interface, CoSe 2 À MoSe 2 /PEDOT, to unravel its bifunctional capability. Low η 10 of À 0.20 V for HER and 1.53 V for OER verified the electrocatalytic performance of this catalyst. We systematically reveal intrinsic point defects and lattice dislocations in these heterostructures. Atomic scale electron microscopy studies disclose presence of V Se and MoÀ Mo bond defects. Spectroscopic techniques are employed to show the altered electronic properties that promote surface oxidation due to the presence of defects. In contrast to MoSe 2 or MoSe 2 / PEDOT, defect rich CoSe 2 À MoSe 2 /PEDOT showed accelerated reaction kinetics with much lower Tafel slopes. Essentially, generation of anion vacancies and metallic MoÀ Mo bonds provide additional sites with improved adsorption properties of the reaction intermediates. This catalyst exhibits excellent electrocatalytic stability upon cycling for both half-cell reactions.

Interlayer Spacing Regulation of Molybdenum Selenide Promotes Electrocatalytic Hydrogen Evolution in Alkaline Media

“…It is worth mentioning that the overpotential of CoSe 2 /MoSe 2 in this work is the smallest among analogous powdered heterostructures and is better than most other related CoSe 2 /MoSe 2 with the conductive substrate (Figure 3c, Table S1, Supporting Information). [14][15][16][17] This indicates that the sample obtained here has excellent morphology and interfacial coupling, which helps to boost the activity. The electrochemically active area is commonly determined using electrochemical double layer capacitance.…”

“…[ 14 ] In fact, the interlayer spacing of MoSe 2 can be extended by inserting organic molecules between the layers, thereby improving its catalytic activity. [ 15 ] However, tuning the interlayer spacing of MoSe 2 by constructing heterojunctions has rarely been reported.…”

Dopamin ve Ürik Asit Tayini İçin 2-Boyutlu MoSe2 Bazlı Elektrokimyasal Sensör Geliştirilmesi

“…MoSe2 daha önce yayınlanan çalışmalara benzer şekilde sentezlenmiştir [16][17]. İki mmol (158 mg) selenyum tozu 10 mL hidrazin hidrat (%50-60) içerisinde dispers edilir.…”

Electrospun cobalt-doped 2D-MoSe2/polypyrrole hybrid-based carbon nanofibers as electrochemical sensing platforms

“…2D-TMD materials contain edge sites, which enable the materials to show high catalytic activities, and their catalytic performance can be controlled by controlling the number of layers [ 17 ]. In particular, molybdenum diselenide (MoSe 2 ), as a typical TMD material, has become very popular for electrochemical applications, including sensors, electrocatalysis, and energy storage due to its unique properties [ 18 – 20 ]. MoSe 2 and its composites have attracted widespread attention due to their unique properties, such as low cost, high electrocatalytic abilities, natural abundance, good electrochemical stability, and band gap [ 21 , 22 ].…”