Co3O4中钴空位的精确构筑来促进羟基氧化物的形成加速水氧化反应
Accurate construction of cobalt vacancies in Co3O4 to promote oxyhydroxide formation for water oxidation
刘志娟 1汪广进 2郭锦瑜 3王燕勇4
作者信息
- 1. State Key Laboratory of Chem/Bio-sensing and Chemometrics,College of Chemistry and Chemical Engineering,Hunan University,Changsha 410082,China;Henan Key Laboratory of Molecular Functional Materials,Henan International Joint Laboratory of Tumor Theranostical Cluster Materials,Green Catalysis Center,and College of Chemistry,Zhengzhou University,Zhengzhou 450001,China
- 2. School of Materials Science and Energy Engineering,Foshan University,Foshan 528000,China
- 3. Henan Key Laboratory of Molecular Functional Materials,Henan International Joint Laboratory of Tumor Theranostical Cluster Materials,Green Catalysis Center,and College of Chemistry,Zhengzhou University,Zhengzhou 450001,China
- 4. State Key Laboratory of Chem/Bio-sensing and Chemometrics,College of Chemistry and Chemical Engineering,Hunan University,Changsha 410082,China
- 折叠
摘要
缺陷位点的引入可以通过增加对反应中间体的亲和力来提高催化剂的催化能力.纳米材料中存在多种缺陷类型,如阳离子缺陷和阴离子缺陷.不同的缺陷位点对电催化性能的贡献不同.因此,构筑缺陷必须精准、明确,以便于确定最优的缺陷类型,促进电化学反应.在这项工作中,我们以钴空位为例,分别成功合成了二价钴空位(Co3O4-VCo(Ⅱ))和三价钴空位(Co3O4-VCo(Ⅲ))的Co3O4.电化学结果表明,钴空位的引入可以显著提高Co3O4的电催化性能.Co3O4-VCo(Ⅱ)表现出最突出的析氧反应(OER)性能,反应动力学速率最快.X射线光电子能谱分析表明,在OER过程中,VCo(Ⅱ)的存在可以使CoOOH活性位点快速形成.密度泛函理论计算表明,钴空位的引入使Co3O4拥有类似金属的导电性.VCo(Ⅱ)的存在使得O p带中心靠近费米能级,自由能势垒降低,电催化剂表面氧交换动力学速率加快,对反应中间体的吸附能最佳,从而表现出优异的电化学性能.本研究为设计高效的富缺陷电催化剂提供了重要指导.
Abstract
The introduction of defect sites has been widely reported to enhance electrocatalysts'abilities by increasing their affinity for reaction intermediates.Many different defect types,such as cation and anion vacancies,can exist in nano-materials.The different defect sites can make different con-tributions to the electrochemical ability.Therefore,a constructed defect should be accurate and specific,which makes it easy to identify the optimal defect type to facilitate electrochemical reactions.In this work,we used cobalt va-cancies in Co3O4 as an example and synthesized Co3O4 with bivalent cobalt vacancies(Co3O4-VCo(Ⅱ))and trivalent cobalt vacancies(Co3O4-VCo(Ⅲ)).Electrochemical results demon-strate that introducing cobalt vacancies considerably enhances the electrocatalytic activity of Co3O4.Furthermore,Co3O4-VCo(Ⅱ)exhibits the most outstanding oxygen evolution ability with the fastest reaction kinetic rate.Quasi-operando X-ray photoelectron microscopy spectrum analysis results indicate that the presence of VCo(Ⅱ)can accelerate CoOOH active site formation during the oxygen evolution reaction process.Density functional theory calculations reveal that introducing cobalt vacancies can endow Co3O4 with metal-like conductivity.The O p-band center can be moved near the Fermi level,and the free energy barrier can be the lowest with the presence of VCo(Ⅱ),resulting in a fast kinetics rate of oxygen exchange at the electrocatalyst surface and optimal adsorption energy to reaction intermediates to display ex-cellent electrochemical ability.This work provides substantial guidance for designing efficient defect-rich electrocatalysts.
关键词
cobalt vacancies/spinel Co3O4/electronic environ-ment/cobalt oxyhydroxides/oxygen evolution reactionKey words
cobalt vacancies/spinel Co3O4/electronic environ-ment/cobalt oxyhydroxides/oxygen evolution reaction引用本文复制引用
基金项目
国家自然科学基金(22272047)
国家自然科学基金(21905088)
国家自然科学基金(22102155)
中国博士后科学基金(2021M692909)
中国博士后科学基金(2022T150587)
湖南省自然科学基金(2022JJ10006)
出版年
2024
NETL
NSTL
万方数据