Density functional theory (DFT) simulations of the oxygen evolution reaction (OER) are considered essential for understanding the limitations of water splitting. Most DFT calculations of the OER use an acidic reaction mechanism and the standard hydrogen electrode (SHE) as reference electrode. However, experimental studies are usually carried out under alkaline conditions using the reversible hydrogen electrode (RHE) as reference electrode. The difference between the conditions in experiment and calculations is then usually taken into account by applying a pH-dependent correction factor to the latter. As, however, the OER reaction mechanisms under acidic and under alkaline conditions are quite different, it is not clear a priori whether a simple correction factor can account for this difference. We derive in this paper step by step the theory to simulate the OER based on the alkaline reaction mechanism and explain the OER process with this mechanism and the RHE as reference electrode. We compare the mechanisms for alkaline and acidic OER catalysis and highlight the roles of the RHE and the SHE. Our detailed analysis validates current OER simulations in the literature and explains the differences in OER calculations with acidic and alkaline mechanisms.

析氧反应 (OER) 的密度泛函理论 (DFT) 模拟被认为对于理解水分解的局限性至关重要。OER 的大多数 DFT 计算使用酸性反应机制和标准氢电极 (SHE) 作为参考电极。然而，实验研究通常在碱性条件下使用可逆氢电极 (RHE) 作为参比电极进行。然后通常通过对后者应用依赖于 pH 的校正因子来考虑实验和计算条件之间的差异。然而，由于酸性和碱性条件下的 OER 反应机制有很大的不同，所以先验的不清楚一个简单的校正因子是否可以解释这种差异。我们在本文中逐步推导出基于碱性反应机理模拟 OER 的理论，并解释了以该机理和 RHE 作为参比电极的 OER 过程。我们比较了碱性和酸性 OER 催化的机制，并强调了 RHE 和 SHE 的作用。我们的详细分析验证了文献中当前的 OER 模拟，并解释了酸性和碱性机制下 OER 计算的差异。