A simple method to approximate electrode potential-dependent activation energies using density functional theory
A simple method to approximate electrode potential-dependent activation energies using density functional theory
复制标题
DOI：
10.1016/j.cattod.2017.01.050
复制
发表时间：
2017-06-15
期刊：
影响因子：
5.3
通讯作者：
Janik, Michael J.
中科院分区：
文献类型：
--
作者：
Akhade, Sneha A.;Bernstein, Nicole J.;Janik, Michael J.
电催化机制的密度泛函理论 (DFT) 检查在燃料电池/电解开发中很有用，但涉及电子和离子转移的基本步骤的电势依赖性活化势垒的计算仍然具有挑战性。提出了一种简单且可转移的 DFT 方法来估计内球电化学反应的这些恒定势垒。寻找电化学反应步骤的过渡态（A*+ H+ + e(-) -> AH*，其中 * 表示表面吸附物质）的挑战可以通过使用等效的类似非电化学反应（A*+ H* -> AH*）来解决。非电化学步骤的过渡态参考平衡电势 (U-0)，在该平衡电势下，类似的非电化学状态 mu(H*) 与其等效电化学状态 mu(H+ + e(-)) 处于平衡状态，从而允许势垒参考本体电解质中离子的化学电势。通过使用马库斯理论推断活化能来合并电势依赖性。 CO2 电还原为 COOH* 的第一个基本步骤用作说明该方法的详细示例。还包括涉及 C-H、O-H 和 N-H 键形成的其他基本还原反应，以证明该方法的可转移性。该方法简单且易于实现，以单个氢化势垒计算的计算成本来近似电势依赖性活化能，并且可以帮助开发用于电化学反应的更具活性和选择性的催化剂。 (C) 2017 Elsevier B.V. 保留所有权利。
Density functional theory (DFT) examination of electrocatalytic mechanisms are useful in fuel cell/electrolysis development, but the calculation of potential-dependent activation barriers for elementary steps involving electron and ion transfer remains challenging. A simple and transferable DFT approach to estimate these constant potential barriers for inner sphere electrochemical reactions is presented. The challenge of finding the transition state for an electrochemical reaction step (A*+ H+ + e(-) -> AH*, where * denotes surface-adsorbed species) is met by using an equivalent analogous non-electrochemical reaction (A*+ H* -> AH*). The transition state of the non-electrochemical step is referenced to an equilibrium potential (U-0), at which the analogous non-electrochemical state mu(H*) is in equilibrium with its equivalent electrochemical state mu(H+ + e(-)), allowing for the barrier to be referenced to the chemical potential of the ion in the bulk electrolyte. The potential-dependence is incorporated by extrapolating the activation energy using Marcus theory. The first elementary step of CO2 electroreduction to COOH* is used as a detailed example case for illustrating the method. Additional elementary reduction reactions involving C-H, O-H and N-H bond formations are included to demonstrate the transferability of the method. The method is simple and easy to implement to approximate potential dependent activation energies at the computational cost of a singly hydrogenation barrier calculation and can aid in the development of more active and selective catalysts for electrochemical reactions. (C) 2017 Elsevier B.V. All rights reserved.