Cysteine-Induced Hybridization of 2D Molybdenum Disulfide Films for Efficient and Stable Hydrogen Evolution Reaction

Abstract

The noble, metal-free materials capable of efficiently catalyzing water splitting reactions currently hold a great deal of promise. In this study, we reported the structure and electrochemical performance of new MoS2-based material synthesized with L-cysteine. For this, a facile one-pot hydrothermal process was developed and an array of densely packed nanoplatelet-shaped hybrid species directly on a conductive substrate were obtained. The crucial role of L-cysteine was determined by numerous methods on the structure and composition of the synthesized material and its activity and stability for hydrogen evolution reaction (HER) from the acidic water. A low Tafel slope of 32.6 mV dec−1, close to a Pt cathode, was registered for the first time. The unique HER performance at the surface of this hybrid material in comparison with recently reported MoS2-based electrocatalysts was attributed to the formation of more defective 1T, 2H-MoS2/MoOx, C nanostructures with the dominant 1T-MoS2 phase and thermally degraded cysteine residues entrapped. Numerous stacks of metallic (1T-MoS2 and MoO2) and semiconducting (2H-MoS2 and MoO3) fragments relayed the formation of highly active layered nanosheets possessing a low hydrogen adsorption free energy and much greater durability, whereas intercalated cysteine fragments had a low Tafel slope of the HER reaction. X-ray photoelectron spectroscopy, scanning electron microscopy, thermography with mass spectrometry, high-resolution transmission electron microscopy, Raman spectroscopy techniques, and linear sweep voltammetry were applied to verify our findings.

Structural Significance of Hydrophobic and Hydrogen Bonding Interaction for Nanoscale Hybridization of Antiseptic Miramistin Molecules with Molybdenum Disulfide Monolayers

“…The Mo 3d spectra of LCs were fitted with four 3d 3/2 –3d 5/2 spin-orbit doublets ( Figure 4 c and Figure S1c ). The Mo 3d 5/2 peaks located at ~228.3, 229.1, 222.3 and 230.4 eV are identified as 1T-MoS 2 modification (octahedral Mo polyhedron), 2H-MoS 2 (trigonal prismatic polyhedron), and impurity MoS x O y and MoO z states that is in accordance with previous studies [ 4 , 5 , 32 ]. The S 2p spectra fitted with four S 2p 3/2 –S 2p 1/2 doublets are shown in Figure 4 d and Figure S1d along with indication of the assigned components.…”

“…Molybdenum disulfide is a famous 2D van der Waals solid, which is considered as one of the most promising post-graphene materials owing to its outstanding properties. These properties are highly demanded for various applications such as advanced field effect transistors [ 1 , 2 ], electrocatalysts [ 3 , 4 , 5 ], biosensors [ 6 ] and energy storage materials [ 7 , 8 ]. Yet another application of MoS 2 has attracted tremendous attention during the last few years, which is based on its excellent photothermal activity.…”

“…During recent years, a number of MoS 2 layered compounds with organic species have been prepared by the soft chemical exfoliation-restacking method [ 4 , 11 ], hydrothermal synthesis [ 5 , 12 ] or surface functionalization [ 13 , 14 ]. Structural modeling and density functional theory (DFT) calculations performed for some such systems have evidenced a strong noncovalent bonding between the MoS 2 sheets and organic molecules as, for example, alkyl(aryl)amines [ 11 , 12 ], phenanthroline [ 4 ], phthalocyanine [ 15 ] and guanidine derivatives [ 16 ].…”