Revealing structure–activity relationships of graphene-supported atomically dispersed transition metal catalysts is of key importance in catalysis chemistry and materials science. Here we report a first-principles theoretical study on O₂ activation and CO oxidation catalyzed by atomically dispersed Pt₁/Pt₂ anchored on a raised graphene (Gr) platform. The unique sharp-tip structure of the protuberant graphene platform (carbon-tip) can collect extra polarization electrons on the Pt-tip, promoting electron transfer between the catalyst and adsorbates, and greatly enhancing the chemical activity. Higher carbon-tips on defective graphene oxide with a carbon vacancy (Gr-V) produce more polarization electrons, a more localized electric field, and a larger up-shift of the d-orbital center of the Pt-tip, resulting in better catalytic performance. The carbon-tip enhancement reduces the energy barrier for the CO oxidation on Pt₁O₂/Gr-V from 1.19 eV to 0.56 eV compared with Pt₁ on planar Gr. In addition, CO poisoning is significantly alleviated, with the CO poisoning rate Γ_θ reduced from 2.00 eV to 0.52 eV. Moreover, a linear relationship between the activation barrier and the binding energy of adsorbates is found for various atomically dispersed Pt-tip catalysts on the raised graphene oxide platform. Importantly, the order of catalytic activity is consistent with the carbon-tip enhancement, i.e., Pt₁O₂/Gr-V > Pt₂O₄/Gr-V > Pt₁O₂/Gr > Pt₂O₄/Gr. These findings provide important guidance for rational design of atomically dispersed catalysts.

中文翻译：

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通过在升高的氧化石墨烯平台上原子分散的Pt1 / Pt2来增强尖端的催化CO氧化

揭示石墨烯负载的原子分散过渡金属催化剂的结构-活性关系在催化化学和材料科学中至关重要。在这里，我们报告有关原子分散的Pt ₁ / Pt ₂催化O ₂活化和CO氧化的第一原理理论研究固定在凸起的石墨烯（Gr）平台上。突出的石墨烯平台的独特尖端结构（碳尖端）可以在Pt尖端上收集额外的极化电子，从而促进催化剂与被吸附物之间的电子转移，并大大增强化学活性。有缺陷的氧化石墨烯上的碳尖端具有较高的碳空位（Gr-V），可产生更多的极化电子，更局限的电场以及Pt尖端的d轨道中心更大的上移，从而产生更好的催化作用性能。与Pt ₁相比，碳尖端增强功能将Pt ₁ O ₂ / Gr-V上的CO氧化的能垒从1.19 eV降低到0.56 eV在平面Gr上 此外，CO中毒显著缓解，与CO中毒率Γ _θ从2.00电子伏特降低到0.52电子伏特。此外，对于在升高的氧化石墨烯平台上的各种原子分散的Pt-tip催化剂，发现了活化势垒与被吸附物的结合能之间的线性关系。重要的是，催化活性的顺序与碳尖端增强一致，即Pt ₁ O ₂ / Gr-V> Pt ₂ O ₄ / Gr-V> Pt ₁ O ₂ / Gr> Pt ₂ O ₄ / Gr。这些发现为合理设计原子分散催化剂提供了重要指导。