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Revealing the Real Role of Nickel Decorated Nitrogen-Doped Carbon Catalysts for Electrochemical Reduction of CO2 to CO
Advanced Energy Materials ( IF 27.8 ) Pub Date : 2021-08-08 , DOI: 10.1002/aenm.202101477
Shuyu Liang 1 , Qian Jiang 2 , Qiang Wang 1 , Yuefeng Liu 2
Affiliation  

It is widely accepted that single Ni atoms coordinated with N can highly efficiently promote CO2 electroreduction to CO. Very recently, probably due to limited access to high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) techniques, a misleading conclusion that nitrogen-doped carbon-encapsulated Ni nanoparticles (NPs) possess activity similar to that of single Ni atoms was reported and was quickly followed by several similar reports. The current contribution aims to end this misleading conclusion by performing well-designed experiments and solid theoretical analyses. For this purpose, a series of Ni/nitrogen-doped graphite (Ni-NG) catalysts with different dominant Ni species (single Ni atom, nitrogen-doped carbon-encapsulated Ni NPs, or both) are fabricated and comparatively studied for CO2 electroreduction to CO. Two previous studies that reported nitrogen-doped carbon-encapsulated Ni NPs catalysts are reinvestigated, and the existence of single Ni atoms is confirmed by HAADF-STEM. In addition, after leaching out most of the Ni NPs by a strong acid, the activity of those catalysts does not decrease but increases slightly. Density functional theory results suggest that nitrogen-doped carbon-encapsulated Ni NPs are highly selective for the hydrogen evolution reaction (HER) rather than for CO2-to-CO conversion. Overall, both systematic experimental and theoretical analyses clearly reveal that the nitrogen-doped carbon-encapsulated Ni NPs are not active for CO2 electroreduction.

中文翻译:

揭示镍装饰的掺氮碳催化剂在将 CO2 电化学还原为 CO 中的真正作用

人们普遍认为,与 N 配位的单个 Ni 原子可以高效地促进 CO 2电还原成 CO。最近,可能是由于对高角度环形暗场扫描透射电子显微镜 (HAADF-STEM) 技术的使用有限,得出了一个误导性结论,即掺氮碳包覆的 Ni 纳米粒子 (NPs) 具有类似于报道了单个 Ni 原子的结果,并很快出现了几个类似的报道。当前的贡献旨在通过进行精心设计的实验和扎实的理论分析来结束这一误导性的结论。为此,制备了一系列具有不同主要 Ni 物种(单个 Ni 原子、氮掺杂碳包封的 Ni NPs,或两者)的 Ni/氮掺杂石墨 (Ni-NG) 催化剂,并比较研究了 CO 2电还原成 CO。 重新研究了先前报道氮掺杂碳包覆的 Ni NPs 催化剂的两项研究,HAADF-STEM 证实了单个 Ni 原子的存在。此外,用强酸浸出大部分Ni NPs后,这些催化剂的活性没有降低,而是略有增加。密度泛函理论结果表明,氮掺杂碳包封的 Ni NPs 对析氢反应 (HER) 具有高度选择性,而不是对 CO 2到 CO 的转化。总的来说,系统的实验和理论分析都清楚地表明,氮掺杂的碳包封的 Ni NPs 对 CO 2电还原没有活性。
更新日期:2021-09-23
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