Laminar-conffned Co9S8 quantum dots within layered hydroxide electrocatalyst for alkaline overall water splitting

Journal:Journal of Alloys and Compounds

Key Words:Layered hydroxide Co9S8 quantum dots Bifunctional electrocatalyst In-situ vulcanization Oxygen vacancies

Abstract:Low hydrogen evolution efficiency and poor conductivity hinder the application of layered hydroxide in overall water splitting. In this work, a CoNiFe- layered ternary hydroxide heterostructure with Co9S8 quantum dot (CoNiFe-LTH/Co9S8 QDs) intercalation was ingeniously designed by using in-situ selective vulcanization and laminar confinement effect. CoNiFe-LTH/Co9S8 QDs exhibits excellent hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and bifunctional electrocatalytic activities in alkaline media. The assembled alkaline electrolyzer requires only 1.59 V to achieve a current density of 100 mA cm�� 2 and demonstrates brilliant durability for over 80 hours. With the aid of electrochemical impedance spectroscopy and theoretical calculations, it is verified that the interlayer Co9S8 QDs enhance the electron transfer the adsorption of H2O between LTH layers, resulting in a great improvement in HER performance. For OER, Co9S8 QDs promote the transformation of CoNiFe-LTH to highly valent active species, while oxygen vacancies (Ov) created by in-situ selective sulfidation as new OH- adsorption activity centers, increasing the intrinsic OER activity of CoNiFe-LTH. Overall, this work provides new inspiration for the rational design of non-precious metal-based bifunctional electrocatalysts.

Co-author:Liang Chu,Shibing Ren

First Author:Zhaokun Wang

Indexed by:Journal paper

Correspondence Author:Mu Yang,Ge Wang

Volume:1031,

Page Number:180978

Translation or Not:no

Date of Publication:2025-05-14

Included Journals:SCI