Relationship between Hydrogen Evolution and Wettability for Multiscale Hierarchical Wrinkles

Abstract

Transition metal dichalcogenides (TMDs) are emerging two-dimensional materials with potential use for the hydrogen evolution reaction (HER) because they express a desired binding energy with protons. To date, TMD-based HER catalytic performance has been enhanced mostly by chemical modification, such as introducing defects, doping, and phase control. Herein, we enhanced the HER performance by precise control of wettability via hierarchical wrinkling. This hierarchical wrinkling confers tunability of the receding contact angle (2−30°) by controlling the wavelength of the hierarchical wrinkles. Minimization of the receding contact angle is directly related to overpotential reduction on the MoS 2 wrinkles through gas detachment from the catalytic surface. Unlike in previous studies, in this work, we demonstrated the effect of wettability only without changing other parameters such as surface chemistry. We showed that our method can be applied to other TMD materials such as WS 2 . This study will contribute to future TMD-based catalyst applications, such as hydrogen evolution, CO 2 reduction, and oxygen evolution.

Recent Advances in Layered Tungsten Disulfide as Electrocatalyst for Water Splitting

“…deposition, and flame vapor deposition, can realize the preparation of controllable layers on different substrates, considering as an effective method for synthesizing two-dimensional materials. For example, Jung et al [78] successfully synthesized WS 2 wrinkles of different thicknesses via chemical vapor deposition on SiO 2 /Si wafers. And WS 2 showed wrinkles structure after adding PVP ( Figure 7a).…”

“… (a) Synthetic process of WS 2 hierarchical wrinkles, (b–f) SEM images of WS 2 hierarchical wrinkles with different wavelength, (g–h) LSV curves and Tafel slopes for all samples in the 0.5 M H 2 SO 4 solution at a scan rate of 5 mV/sec, (i) the relationship for the overpotential and receding contact angles with different G 2 wavelength, (j) gas separation with the receding contact angle. Reproduced with permission . Copyright © 2019, American Chemical Society.…”

Advanced Bifunctional Oxygen Reduction and Evolution Electrocatalyst Derived from Surface‐Mounted Metal–Organic Frameworks

“…[4] Among alarge number of state-of-the-art electrode materials capable to efficiently catalyze both reactions,m etal-organic frameworks (MOFs) and their derivatives have attracted considerable attention due to their tunable lattice structures, porosity and well-defined compositions,j ust to name af ew aspects. [5] However,t he previously reported MOF-based materials including MOF derived materials typically had alow density of accessible active sites.O nt he other hand, recent studies have shown that the number of catalytic centers can be increased by exfoliating catalysts into nanosheets, [6] through phosphorylation of materials (leading to various hierarchy), by increasing their wettability [7] or nanostructuring. [8] Such catalysts are typically utilized as microcrystalline powders drop-casted onto electrodes by adding hydrophilic binders.…”

Topological structures of transition metal dichalcogenides: A review on fabrication, effects, applications, and potential

“…Recently, there have been studies exploring controllable methods for the fabrication of wrinkles, folds, and scrolls on TMD materials 56‐58,69‐73 . The preparation of wrinkled TMD structures often involves the transfer of the TMDs to a pre‐stretched polymer or rigid substrates with pre‐defined microstructures and thermally induced polystyrene (PS) substrate 56‐58,74‐84 . To reduce bending rigidity, wrinkles are collapsed and reconstructed to folds 85 .…”