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Graphdiyne-Supported Single-Atom-Sized Fe Catalysts for the Oxygen Reduction Reaction: DFT Predictions and Experimental Validations
ACS Catalysis ( IF 11.3 ) Pub Date : 2018-10-02 00:00:00 , DOI: 10.1021/acscatal.8b02360
Yuan Gao 1 , Zhewei Cai 2 , Xingchen Wu 1 , Zhilie Lv 1 , Ping Wu 1 , Chenxin Cai 1
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Single-atom-sized catalysts (often called single atom catalysts) are highly desired for maximizing the efficiency of metal atom use. However, their synthesis is a major challenge that largely depends on finding an appropriate supporting substrate to achieve a well-defined and highly dispersed single atom. This work demonstrates, based on density functional theory (DFT) predictions and experimental validations, that graphdiyne is a good substrate for anchoring Fe atoms through the formation of covalent Fe–C bonds to produce graphdiyne-supported single-atom-sized Fe catalysts (Fe–graphdiyne catalysts); moreover, this catalyst shows high catalytic activity to oxygen reduction reactions (ORRs) similar to or even slightly better than the precious metal benchmark (commercial 20 wt % Pt/C catalyst). DFT predicts that the O2 molecule can bind with an Fe atom, and the electron transformation process of ORRs occurs through a 4e pathway. To validate the theoretical predictions, the Fe–graphdiyne catalyst was then synthesized by a reduction of Fe3+ ions adsorbed on a graphdiyne surface in aqueous solution, and its electrocatalytic activities toward ORR were experimentally evaluated in alkaline electrolytes (0.1 M KOH). The electrochemical measurements indicate that the Fe–graphdiyne catalyst can facilitate the 4e ORR while limiting the 2e transfer reaction, showing a high 4e selectivity for ORRs and a good agreement with DFT predictions. The results presented here demonstrate that graphdiyne can provide a unique platform for synthesizing well-defined and uniform single-atom-sized metal catalysts with high catalytic activity toward ORRs.

中文翻译:

石墨二炔支持的单原子尺寸铁催化剂的氧还原反应:DFT预测和实验验证

为了最大化使用金属原子的效率,非常需要单原子尺寸的催化剂(通常称为单原子催化剂)。然而,它们的合成是一个主要的挑战,很大程度上取决于寻找合适的支撑底物以实现定义明确且高度分散的单个原子。这项工作基于密度泛函理论(DFT)的预测和实验验证表明,石墨二炔是通过形成共价Fe–C键来锚固Fe原子以生产石墨二炔负载的单原子尺寸Fe催化剂的良好基质(Fe –graphdiyne催化剂);此外,该催化剂显示出对氧还原反应(ORR)的高催化活性,类似于或什至略好于贵金属基准(商业上20重量%的Pt / C催化剂)。DFT预测O 2分子可以与Fe原子结合,和ORRs的电子转化过程通过4E发生-通路。为了验证理论预测,然后通过还原水溶液中吸附在石墨二炔表面的Fe 3+离子来合成Fe–graphdiyne催化剂,并在碱性电解质(0.1 M KOH)中通过实验评估了其对ORR的电催化活性。电化学测量表明,Fe–graphdiyne催化剂可促进4e ORR,同时限制2e 转移反应,显示出较高的4e ORR 对ORR的选择性以及与DFT预测的良好一致性。此处给出的结果表明,graphdiyne可以提供一个独特的平台,用于合成对ORR具有高催化活性的定义明确且均匀的单原子尺寸金属催化剂。
更新日期:2018-10-02
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