d带中心调控过渡金属单原子负载COF吸附O2的理论计算研究
d-Band Center Regulated O2 Adsorption on Transition Metal Single Atoms Loaded COF:A DFT Study
谢斐 1袁成成 1谭海燕 2Alireza Z.Moshfegh 3朱必成 1余家国1
作者信息
- 1. 中国地质大学(武汉),材料与化学学院,太阳燃料实验室,武汉 430078
- 2. 湖北民族大学,化学与环境工程学院,湖北 恩施 445000
- 3. Institute for Nanoscience and Nanotechnology,Department of Physics,Sharif University of Technology,Tehran 11365-8639,Iran
- 折叠
摘要
共价有机框架(COF)材料因其独特的结构和物理化学特性成为一种很有前景的光催化剂.为了提高其光催化性能,大量的金属单原子(MSA)被负载在COF上以促进分子吸附.然而,吸附性能增强的内在机理和主导因素尚未被深入揭示.本文通过在单层TpBpy-COF中分别引入Fe、Co、Ni和Cu单原子,构建了4个MSA-COF体系.利用密度泛函理论计算研究了不同金属原子修饰对COF的电子性质和O2吸附的影响.结果表明,金属原子与吡啶氮原子成键,形成稳定的MSA-COF结构.金属原子的引入减小了COF的带隙,抬高了COF的费米能级.此外,随着金属原子序数的增加,金属原子的d轨道逐渐向低能级方向移动,表现为d带中心负移.金属原子负载后,COF对O2的弱物理吸附转变为强化学吸附,形成了M―Oads键,并发生强烈的电子转移.有趣的是,吸附能与金属原子的d带中心呈现出很强的相关性.该结果可以从吸附体系反键轨道的电子占据情况的角度来理解.本研究为通过调节金属原子的d带中心来优化MSA-COF上的分子吸附提供了一种可行思路.
Abstract
Covalent organic framework(COF)materials are promising photocatalysts because of their fantastic structural and physicochemical features.To enhance photocatalytic performance,numerous metal single atoms(MSA)are loaded on COF to improve molecule adsorption.However,the inherent mechanisms and dominant factors of the heightened adsorption property are not deeply unveiled.Herein,four MSA-COF systems were constructed by severally introducing Fe,Co,Ni,and Cu single atoms in monolayer TpBpy-COF.The effect of various metal atoms modification on the electronic property and O2 adsorption of COF was investigated using density functional theory calculations.The results show that the metal atoms are bonded to the pyridinic N atoms,forming stable MSA-COF configurations.The anchoring of metal atoms reduces the band gap and raises the Fermi level of COF.Moreover,as the atomic number of the metals increases,the d orbitals of the metal atoms gradually move to lower energy levels,manifesting a negative shift of the d-band centers.After metal atoms loading,the weak physical adsorption of O2 on pristine COF is converted to robust chemisorption with the formation of M―Oads bonds and intense electron transfer.Intriguingly,the adsorption energy presents a strong correlation with the d-band centers of the metal atoms.This finding is comprehended from the perspective of electron occupancy in antibonding orbitals in the adsorption systems.This work provides a feasible approach for modifying molecule adsorption on MSA-COF by regulating the d-band centers of metal atoms.
关键词
共价有机框架/金属单原子/O2吸附/d带中心/光催化Key words
Covalent organic framework/Metal single atom/O2 adsorption/d-band center/Photocatalysis引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据