催化学报

催化学报 ›› 2022, Vol. 43 ›› Issue (11): 2889-2897.DOI: 10.1016/S1872-2067(22)64161-5

• 论文 • 上一篇    下一篇

高熵合金的鸡尾酒效应和线性标度关系打破效应于电催化火山曲线上的标记

陈俊翔a,*(), 吉雅欣a,b   

  1. a中国科学院福建物质结构研究所, 结构化学国家重点实验室, 中科院功能纳米结构与组装重点实验室, 福建福州 350002
    b福建师范大学化学与材料学院, 福建福州 350007
  • 收稿日期:2022-04-12 接受日期:2022-08-04 出版日期:2022-11-18 发布日期:2022-10-20
  • 通讯作者: 陈俊翔
  • 基金资助:
    结构化学国家重点实验室基金(20210025);福建省自然科学基金(2021J01526)

Locating the cocktail and scaling-relation breaking effects of high-entropy alloy catalysts on the electrocatalytic volcano plot

Junxiang Chena,*(), Yaxin Jia,b   

  1. aState Key Laboratory of Structural Chemistry, and CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian, China
    bCollege of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, Fujian, China
  • Received:2022-04-12 Accepted:2022-08-04 Online:2022-11-18 Published:2022-10-20
  • Contact: Junxiang Chen
  • Supported by:
    Science Foundation of State Key Laboratory of Structural Chemistry(20210025);Science Foundation of Fujian Province(2021J01526)

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摘要：

在电催化研究中, 高熵合金是一类明星材料. 相比于传统低熵化合物, 高熵合金通过提升材料的活性位点多样性, 在催化活性层面, 能够带来两个明显的优势效应. 一是所谓的”鸡尾酒效应”, 即反应位点的相互组合能够调和出极优化的位点; 二是线性标度关系的打破效应, 是指由于反应中间体的化学性质差异以及可能的吸附物表面迁移, 使得各个中间体键合在不同的反应位点, 从而打破线性标度关系. 但是, 这两个效应的定量却较为复杂, 一个重要的原因, 是其超出了当前电催化研究中常使用的, 基于计算氢电极方法的电催化理论框架(ETF)的适用范围. ETF用单一吸附能来表示催化剂, 也就是火山关系中的一个“点”, 然而鸡尾酒效应, 却导致吸附能以一个分布的形式存在; 另外, 线性标度关系打破效应甚至挑战了火山关系的存在性这一ETF的理论基础. 这些问题促使科研人员考虑发展一个方法, 在火山曲线上表示这两个效应, 从而使得高熵合金电催化更适宜用ETF进行描述.

本文从高熵合金催化剂上吸附能的分布入手. 首先, 根据以往的理论计算结果, 以及吸附的特性, 得出吸附能服从正态分布. 在此基础上, 利用正态分布的优良的数学特性推导得出, 可使用平均吸附能和吸附能方差的简单代数加和形式, 来表示高熵合金的上述两个效应. 利用这套关系, 便可简单地在电催化火山曲线上, 像对于低熵/一元催化剂那样, 继续使用一个“点”来描述高熵合金催化剂. 鉴于方差和平均吸附能都是较容易计算的物理量, 本文方法可以延续ETF的简洁性. 由此, 便可将ETF扩展至高熵合金电催化.

关键词: 高熵合金, 电催化, 理论火山曲线, 鸡尾酒效应, 线性标度关系打破效应, 吸附能分布

Abstract:

High entropy alloys (HEAs) have been the star materials in electrocatalysis research in recent years. One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic materials. This increased multiplicity stimulates a cocktail effect and a scaling-relation breaking effect, and results in improved activity. However, the multiplicity of active sites in HEAs also poses new problems for mechanistic studies. One apparent problem is the inapplicability to HEA catalysts of the currently most popular mechanistic study method, which uses the electrocatalytic theoretical framework (ETF) based on the computational hydrogen electrode (CHE). The ETF uses a single adsorption energy to represent the catalyst, i.e., a catalyst is represented by a 'point' in the volcanic relationship. It naturally does not involve the multiplicity of active sites of a catalyst, and hence loses brevity in expressing the cocktail effect and scaling-relation breaking effect in HEA catalysis. This paper attempts to solve this inapplicability. Based on the fact that the adsorption energy distribution of HEAs is close to a normal distribution, the mean and variance of the adsorption energy distribution are introduced as descriptors of the ETF, replacing the original single adsorption energy. A quantitative relationship between the variance and the cocktail and scaling-relation braking effects is established. We believe the method described in this work will make the ETF more effective in mechanistic studies of HEA electrocatalysis.

Key words: High-entropy alloy, Electrocatalysis, Volcano plot, Cocktail effect, Scaling-relation breaking effect, Adsorption energy distribution