Layer‐by‐Layer Assembly‐Based Electrocatalytic Fibril Electrodes Enabling Extremely Low Overpotentials and Stable Operation at 1 A cm−2 in Water‐Splitting Reaction. (12th June 2021)

• Record Type: Journal Article
• Authors: Ko, Younji; Park, Jinho; Mo, Jeongmin; Lee, Seokmin; Song, Yongkwon; Ko, Yongmin; Lee, Hoyoung; Kim, Yongju; Huh, June; Lee, Seung Woo; Cho, Jinhan
• Is Part Of: Advanced functional materials. Volume 31:Number 35(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-12
• Subjects: electrocatalytic fibrils -- layer‐by‐layer assembly -- water splitting reaction; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202102530
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: For the practical use of water electrolyzers using non‐noble metal catalysts, it is crucial to minimize the overpotentials for the hydrogen and oxygen evolution reactions. Here, cotton‐based, highly porous electrocatalytic electrodes are introduced with extremely low overpotentials and fast reaction kinetics using metal nanoparticle assembly‐driven electroplating. Hydrophobic metal nanoparticles are layer‐by‐layer assembled with small‐molecule linkers onto cotton fibrils to form the conductive seeds for effective electroplating of non‐noble metal electrocatalysts. This approach converts insulating cottons to highly electrocatalytic textiles while maintaining their intrinsic 3D porous structure with extremely large surface area without metal agglomerations. To prepare hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrodes, Ni is first electroplated onto the conductive cotton textile (HER electrode), and NiFe is subsequently electroplated onto the Ni–electroplated textile (OER electrode). The resulting HER and OER electrodes exhibit remarkably low overpotentials of 12 mV at 10 mA cm −2 and 214 mV at 50 mA cm −2, respectively. The two‐electrode water electrolyzer exhibits a current density of 10 mA cm −2 at a low cell voltage of 1.39 V. Additionally, the operational stability of the device is well maintained even at an extremely high current density of 1 A cm −2 for at least 100 h. Abstract : An electrocatalytic fibril‐based water splitting electrode that can significantly increase the activity of electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction is introduced. To prepare the electrocatalytic fibril electrodes with Ni and NiFe layers, a LbL‐assembled metal nanoparticle‐driven electroplating approach is applied to highly porous cotton textiles.