Abstract As carbon materials are cheap and versatile, they are widely used materials for heterogeneous catalysis in general and for electrocatalysis in particular. However, they are prone to degradation, particularly under oxidative conditions. While electronic structure theory has been applied to study structure and thermodynamics in materials science, in many cases kinetic stability is the key feature which is associated with mechanisms and barriers. To compute these in aqueous medium and under electrode potential, we devise a DFT + implicit solvation scheme using a constant potential approach. Considering both pH and potential on a polycyclic aromatic hydrocarbon (PAH) model, we find a low energy pathway for graphitic carbon degradation. Depending on the pH and the potential, barrierless hydroxylation followed by deprotonation is observed at the PAH’s edges. At low pH and potential, the material is expected to remain pristine, at intermediate potential it exhibits few ketone and alcohol groups at its edges, and at high potential no barriers are found for hydroxylation processes, leading to CO2 formation and significant deformation of the material. We also observe smaller PAHs and nitrogen doped PAHs exhibit increased stability, which we attribute to their increased oxidation potentials.

中文翻译：

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使用电子结构方法研究石墨碳材料在电催化中的稳定性

摘要 由于碳材料价格低廉且用途广泛，因此它们是广泛用于一般多相催化，特别是电催化的材料。然而，它们易于降解，特别是在氧化条件下。虽然电子结构理论已应用于材料科学中的结构和热力学研究，但在许多情况下，动力学稳定性是与机制和障碍相关的关键特征。为了在水介质中和在电极电位下计算这些，我们使用恒定电位方法设计了 DFT + 隐式溶剂化方案。考虑到多环芳烃 (PAH) 模型的 pH 值和电位，我们发现了石墨碳降解的低能量途径。根据 pH 值和电位，在 PAH 的边缘观察到无障碍羟基化和去质子化。在低 pH 值和电位下，材料有望保持原始状态，在中等电位下，其边缘几乎没有酮和醇基团，而在高电位下，没有发现羟基化过程的障碍，导致 CO2 形成和材料显着变形. 我们还观察到较小的 PAH 和氮掺杂的 PAH 表现出更高的稳定性，我们将其归因于它们增加的氧化电位。