Lai Qingxue, Zheng Hongmei, Tang Zeming, Bi Da, Chen Ningning, Liu Xingjiang, Zheng Jing, Liang Yanyu
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, No. 29 Yudao St., Nanjing 210016, P. R. China.
Science and Technology on Power Sources Laboratory, Tianjin Institute of Power Sources, No. 6 Huake 7 Road, Haitai Ave., Tianjin 300384, P. R. China.
ACS Appl Mater Interfaces. 2021 Dec 29;13(51):61129-61138. doi: 10.1021/acsami.1c18451. Epub 2021 Dec 15.
Nitrogen-doped nanocarbon materials (NCMs) have been developed as promising metal-free oxygen reduction reaction (ORR) electrocatalysts. However, insufficient attention on the balance of N-doping engineering and carbon chemistry significantly suppressed the revelation of the real active configurations as well as the ORR mechanism for NCMs. Herein, 1,4-phenylenediurea (BDU) with multifunctional blocks was designed for the synthesis of NCMs, realizing synchronous manipulation of N-doping engineering and carbon chemistry. The good balance between N-doping engineering (especially graphitic edge N configurations) and carbon chemistry (including the specific surface area, porosity distribution, and graphitization degree) at a pyrolysis temperature of 1000 °C resulted in the best ORR performance for obtaining N-doped carbon nanorod (NCR) materials. A general descriptor χ was then proposed for evaluating the balance states between N-doping engineering and carbon chemistry. The prediction of the ORR performance of NCMs from their physical properties as well as searching for the optimal active configuration from the relationships between ORR performance and different configurations can be realized from such a practical descriptor, which can also be extended to other nanocarbon-based metal-free electrocatalytic reactions for deeply understanding their electrocatalytic mechanisms.
氮掺杂纳米碳材料（NCMs）已被开发成为有前景的无金属氧还原反应（ORR）电催化剂。然而，对氮掺杂工程与碳化学平衡的关注不足，显著抑制了NCMs真实活性构型以及ORR机理的揭示。在此，设计了具有多功能嵌段的1,4-苯二脲（BDU）用于合成NCMs，实现了氮掺杂工程与碳化学的同步调控。在1000℃的热解温度下，氮掺杂工程（特别是石墨边缘氮构型）与碳化学（包括比表面积、孔隙率分布和石墨化程度）之间的良好平衡，使得获得氮掺杂碳纳米棒（NCR）材料的ORR性能最佳。然后提出了一个通用描述符χ来评估氮掺杂工程与碳化学之间的平衡状态。通过这样一个实用的描述符，可以从NCMs的物理性质预测其ORR性能，以及从ORR性能与不同构型之间的关系中寻找最佳活性构型，这也可以扩展到其他基于纳米碳的无金属电催化反应，以深入理解其电催化机理。
