A metadynamics method was used to calculate the free energy surfaces (FESs) of the oxygen evolution reaction (OER). Metadynamics simulation suggests that the oxygen–oxygen (O−O) bond formation induced by oxidative reactant species and oxygen atoms on the surface is the rate-determining step. Not only bond distances but also extended social permutation invariant (xSPRINT) coordinates and deep autoencoder neural network (DAENN) are used as collective variables (CVs) in metadynamics calculations to characterize the FESs of the studied reactions. The FES calculations using xSPRINT and DAENN CVs show that the formation of OH• and H2O2, respectively, is more energetically (in terms of the free-energy barrier) favorable than the formation of oxygen gas at the WO3 surface/liquid-water interface. It is found that the O−O bond formation is sluggish because of the stable electronic state of the surface and that the formation of OH• and H2O2 occurs through an energy barrierless process.

中文翻译：

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(001)-WO3/液-水界面水氧化反应的元动力学研究


使用元动力学方法计算析氧反应（OER）的自由能表面（FES）。元动力学模拟表明，氧化反应物和表面氧原子诱导的氧-氧（O−O）键形成是速率决定步骤。在元动力学计算中，不仅使用键距离，而且还使用扩展社会排列不变（xSPRINT）坐标和深度自动编码器神经网络（DAENN）作为集体变量（CV）来表征所研究反应的FES。使用 xSPRINT 和 DAENN CV 进行的 FES 计算表明，在 WO3 表面/液态-水界面处，OH• 和 H2O2 的形成（就自由能势垒而言）比氧气的形成更加有利。研究发现，由于表面电子态稳定，O−O 键的形成缓慢，并且 OH• 和 H2O2 的形成是通过无能垒过程发生的。