含氮石墨烯基电催化剂中氢化吡啶和吡咯氮的核心能级变化：面内缺陷与边缘缺陷,The Journal of Physical Chemistry C

当前位置： X-MOL 学术 › J. Phys. Chem. C › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

含氮石墨烯基电催化剂中氢化吡啶和吡咯氮的核心能级变化：面内缺陷与边缘缺陷
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2016-12-15 00:00:00 , DOI: 10.1021/acs.jpcc.6b09778
Ivana Matanovic _{1,

2} , Kateryna Artyushkova ₁ , Matthew B. Strand ₃ , Michael J. Dzara ₃ , Svitlana Pylypenko ₃ , Plamen Atanassov ₁

Affiliation

结合使用N 1s X射线光电子能谱（XPS）和含氮模型电催化剂的第一性原理计算来阐明氮缺陷的性质，这些缺陷会影响N 1s XPS光谱的结合能（BE）范围。这些材料高于〜400 eV。获得了一组模型材料的实验核心能级位移，即N掺杂碳纳米球，Fe–N–碳纳米球，聚吡咯，聚吡啶和氯化吡啶鎓，并与使用密度泛函理论计算的位移进行了比较。结果证实，在含氮催化剂的N 1s XPS光谱中，位于〜400.7 eV处的宽峰通常被指定为吡咯氮，包含来自其他氢化氮物质的贡献，例如氢化吡啶二酮官能度。即使用Perdew-Burke-Ernzerhof交换相关函数，氢化吡啶二氮和吡咯N的N 1s BEs分别计算为400.6和400.7 eV。重点放在研究石墨烯片的平面和边缘上的含氮缺陷在XPS压印上的差异。面内和边缘缺陷的N 1s的BE的密度泛函理论计算表明，氢化的N缺陷比未氢化的N缺陷对碳基质中化学环境的变化更敏感。计算还表明，如果石墨烯的边缘被氧化或被裸露的碳原子封端，则边缘氢化的吡啶-N和吡咯-N缺陷只会对位于〜约400.7 eV的N 1s XPS峰有贡献。

"点击查看英文标题和摘要"

Core Level Shifts of Hydrogenated Pyridinic and Pyrrolic Nitrogen in the Nitrogen-Containing Graphene-Based Electrocatalysts: In-Plane vs Edge Defects

A combination of N 1s X-ray photoelectron spectroscopy (XPS) and first principles calculations of nitrogen-containing model electrocatalysts was used to elucidate the nature of the nitrogen defects that contribute to the binding energy (BE) range of the N 1s XPS spectra of these materials above ∼400 eV. Experimental core level shifts were obtained for a set of model materials, namely N-doped carbon nanospheres, Fe–N–carbon nanospheres, polypyrrole, polypyridine, and pyridinium chloride, and were compared to the shifts calculated using density functional theory. The results confirm that the broad peak positioned at ∼400.7 eV in the N 1s XPS spectra of N-containing catalysts, which is typically assigned to pyrrolic nitrogen, contains contributions from other hydrogenated nitrogen species such as hydrogenated pyridinic functionalities. Namely, N 1s BEs of hydrogenated pyridinic-N and pyrrolic-N were calculated as 400.6 and 400.7 eV, respectively, using the Perdew–Burke–Ernzerhof exchange-correlation functional. A special emphasis was placed on the study of the differences in the XPS imprint of N-containing defects that are situated in the plane and on the edges of the graphene sheet. Density functional theory calculations for BEs of the N 1s of in-plane and edge defects show that hydrogenated N defects are more sensitive to the change in the chemical environment in the carbon matrix than the non-hydrogenated N defects. Calculations also show that edge-hydrogenated pyridinic-N and pyrrolic-N defects only contribute to the N 1s XPS peak located at ∼400.7 eV if the graphene edges are oxygenated or terminated with bare carbon atoms.

更新日期：2016-12-15

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南