Electrifying Schiff-based networks as model catalysts towards deeply understanding the crucial role of sp2-carbon in nitrogen-doped carbocatalyst for oxygen reduction reaction

• Published in: Applied surface science Vol. 599; p. 153961
• Main Authors: Xiao, Zhichang, Mou, Xiaofeng, Meng, Xufeng, Yang, Qi, Ma, Yingjie, Zhao, Nan, Huang, Xiaoxiong, Shaislamov, Ulugbek, Kong, Debin, Zhi, Linjie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2022
• Subjects: Chemical microenvironment; Nitrogen doped carbocatalyst; Oxygen reduction reaction; Schiff base chemistry; Sp2-carbon; Schiff base chemistry; Nitrogen doped carbocatalyst; Sp2-carbon; Chemical microenvironment; Oxygen reduction reaction
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.153961

Regularly varied sp2 carbon content and controllable nitrogen configuration are fulfilled through a rationally designed Schiff base chemistry approach. Combining theoretical and experimental methods, electron-conductive quaternary-N site (ENS) is proposed by integrating the contents of quaternary nitrogen with sp2 carbon. This work provides an ideal model system to testify the detailed correlation between ORR performance and sp2 carbon chemistry, and open up a new avenue for the prediction of ORR performance on molecular level. [Display omitted] •Sp2 carbon is demonstrated to be capable of improving the ORR activity of the nitrogen active sites only within an appropriate content.•Electron-conductive nitrogen site (ENS) is established to quantitatively integrate the content of nitrogen active sites and sp2 carbon.•ORR performance is demonstrated to be predictable according to the controllable N configuration and sp2 carbon content.•The optimized NEC catalyst exhibits excellent ORR activity and promising potential as cathode materials for zinc-air batteries. Deeply understanding the correlation between chemical microenvironment and oxygen reduction reaction (ORR) performance is highly desired for developing efficient heteroatom-doped carbocatalysts, yet the detailed structure of chemical microenvironment remains ambiguous. Herein, a series of nitrogen-enriched carbon composites (NEC) with controllable nitrogen configuration and regularly varied sp2 carbon content are successfully developed through a rationally designed Schiff-base chemistry approach, which provides an ideal model system to testify the detailed correlation between ORR performance and sp2 carbon chemistry. By adopting vertical ionization energies (VIE) as assessments for ORR performance, the density functional theory (DFT) calculations reveal that the nitrogen-doped carbocatalyst with high sp2 carbon content possesses remarkable electrocatalytic activity. Furthermore, an important structural parameter, electron-conductive quaternary-N site (ENS) integrating the contents of quaternary nitrogen with sp2 carbon, is proposed, which exhibits well-fitted result with the value of VIE, and agrees well with the experimental results of ORR performance. Benefiting from those advantageous nanostructures, the resultant NECs exhibits excellent catalytic activity for ORR with a high half-wave potential of 0.80 V and promising potential as cathode materials for zinc-air batteries. Therefore, the present study may open up a new avenue for the design and prediction of ORR performance on molecular level.