Multidimensional Thin Film Hybrid Electrodes with MoS₂ Multilayer for Electrocatalytic Hydrogen Evolution Reaction

Abstract

Hybrid electrodes are widely used in various energy storage and conversion devices. However, conventional fabrication methods like simple mixing allow only limited control over the internal electrode structure, and it is often difficult to elucidate the structure-property relationship among the electrode components. Taking advantage of the versatile layer-by-layer (LbL) assembly method, herein we report the preparation of electrocatalytic thin film electrodes for hydrogen evolution reaction (HER), highlighting the importance of nanoscale composition in multidimensional hybrid electrodes. The fabrication utilized the electrostatic interaction between the two components: catalytically active two-dimensional MoS nanosheets and conductive, one-dimensional multiwalled carbon nanotube (MWNT) support. The electrocatalytic activity was found to be highly tunable by adjusting the thickness of the electrode, suggesting structural dependence of electron transfer and mass transport between the electrolyte and electrode, which is otherwise difficult to investigate in electrodes fabricated by simple conventional methods. Furthermore, the detailed mechanism of HER on the hybrid electrode was also investigated, revealing the fine balance between the catalytic activity of MoS and conductivity of MWNT. We anticipate that this unique approach will offer new insights into the nanoscale control of electrode architecture and the development of novel electroactive catalysts.

A Scalable Interfacial Engineering Strategy for a Finely Tunable, Homogeneous MoS2/rGO‐Based HER Catalytic Structure

“…This phenomenon can be attributed to the competing effect between an increase in the amount of active sites and a decrease in the electron transfer efficiency (growth of resistance). [ 25 ] The optimized assembly number is thus determined to be 16 bilayers.…”

Layer‐by‐Layer Assembly: Recent Progress from Layered Assemblies to Layered Nanoarchitectonics

“…In agreement with observations reported elsewhere, the optimum thickness varied with ag iven set of reactionc onditions, components, and structures of the LbL assembly. [77,79,88] This observation highlights the importance of LbL assemblies, which offer precise control over electrode architecture to achieve optimal performance of the assembled nanoscale composite materials.…”

“…2019, 14,2553 -2566 www.chemasianj.org cantly expanding the LbL toolkit. [77][78][79][80] Various organic compounds/GOhybrid materials have been createdbyusing physiochemical approaches, thereby improving the processability of these materials in different solvents and utilizing the outstanding properties of the attached molecules. [81] Aw ide range of organic compounds, including aromatic dyes, ionic liquids,a nd pyrene derivatives, have also been anchored onto GO nanosheets,either in ac ovalent or noncovalent manner, for applications in catalysis, electronic devices, and solar cells.…”

“…The performance of LbL-assembled multilayers is dependent on the number of layers, which is closelyr elated to the film thickness. [79,86,87] The LbL-assembly techniquee nhances the stability of nanoparticles on graphene sheetsa nd can be used to controlt he performance of graphene-based hybrid multilayers by adjusting the number of layers. Severals tudies have demonstrated that controlling the thickness of LbL-assembled hybrid films significantly affectst heir activity,s uch as in methanol oxidation.…”

Graphene wrinkle effects on molecular resonance states

“…37 Further information on site-dependent discrepancies in molecular resonance will aid efforts to predict the performance of large-scale devices integrated with electrodes made from graphene and other 2-D layered materials. 38 Here we report the adsorption patterns and electronic states of pentacene adsorbed on wrinkled and flat regions of CVD-grown graphene, measured using atomic force microscopy (AFM), scanning tunneling microscopy (STM), and spectroscopy (STS). The topographic information reveals different growth configurations of pentacene which depend on the graphene landscape, from the assembly of ribbon-like architectures on top of the wrinkles to the emergence of island type patterns on flat regions within a single graphene grain.…”