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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >A first-principles investigation of oxygen reduction reaction catalysis capabilities of As decorated defect graphene
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A first-principles investigation of oxygen reduction reaction catalysis capabilities of As decorated defect graphene

机译：砷修饰缺陷石墨烯氧还原反应催化能力的第一性原理研究

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Single and multiple As adatom adsorptions on double vacancy (DV) defect graphene sheets are extensively analyzed using dispersive force corrected density functional theory (DFT). Defect pentagonal and heptagonal bridge sites and the immediate neighborhood of the defect center are found to be most favorable for this purpose. Quantitative analysis of electronic structures revealed the As-C bonding to be mostly ionic in nature with some covalency arising from the overlap of As p states and C p states. For multiple As adatoms adsorption in close vicinity, ionicity of the As-C bonds are found to decrease to support As-As cohesion; the net result of which is manifested as better binding of dioxygen molecule with them and additional weakening of the O-O bond in the adsorbed state. Free energy profile of oxygen reduction reaction (ORR) cycle using multiple As atom adsorbed DV graphene as electrocatalyst predicts high affinity towards four electron process and forbids the formation of H_2O_2 via two electron process. Other traits, such as no intermediate O-O-H formation and high stability of the catalytic system throughout the reaction process indicate As adatoms adsorbed on DV graphene system to be efficient and highly stable as an alternate Pt free ORR electrocatalyst.
机译：使用分散力校正密度泛函理论（DFT）对双空位（DV）缺陷石墨烯片材上的单原子和多原子As吸附原子进行了广泛分析。发现缺陷五边形和七边形桥位以及缺陷中心的直接邻域最适合此目的。电子结构的定量分析表明，As-C键本质上主要是离子键，并且由于As p状态和C p状态的重叠而产生一些共价键。对于紧邻附近的多个As原子吸附，发现As-C键的离子性降低，从而支持As-As的内聚力。其最终结果表明，双氧分子与它们之间的结合更好，并且在吸附状态下O-O键进一步减弱。使用多个As原子吸附的DV石墨烯作为电催化剂的氧还原反应（ORR）循环的自由能谱预测对四电子过程具有高亲和力，并禁止通过两电子过程形成H_2O_2。其他特征，例如没有中间的O-O-H形成和整个反应过程中催化体系的高稳定性，表明吸附在DV石墨烯体系上的As原子作为替代的无Pt ORR电催化剂是高效且高度稳定的。

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