open access

https://hdl.handle.net/2115/97825

Why Does the Performance of Nitrogen-Doped Carbon Electrocatalysts Decrease in Acidic Conditions?

英語

Surface science

2025-05-02

Wiley-Blackwell

Angewandte chemie-international edition

Nitrogen-doped carbon has emerged as a promising low-cost and durable alternative to platinum catalysts for the oxygen reduction reaction (ORR) in fuel cells. However, its catalytic activity decreases significantly in acidic electrolytes, limiting the practical applications. Here, we report the degradation mechanisms of nitrogen-doped carbon catalysts, focusing on the acid-base equilibrium of pyridinic nitrogen (pyri-N), which serves the primary active site. We found that the electrochemical hydrogenation of pyri-N to pyri-NH, coupled with oxygen adsorption, is a critical process. Although this reaction occurs at higher potentials in basic electrolytes, it shifts to lower potentials in acidic environments due to the protonation and stabilization of pyri-N. These results demonstrate that the decrease of the catalytic activity in acidic electrolytes is tied to the basicity of pyri-N. By controlling the basicity of pyri-N, specifically its pKa, a guideline for enhancing the ORR and other electrode reactions has been established.

学術雑誌論文

Accepted Manuscript

This is the peer reviewed version of the following article: Kenji Hayashida, Junji Nakamura, Kotaro Takeyasu, Why Does the Performance of Nitrogen-Doped Carbon Electrocatalysts Decrease in Acidic Conditions?, Angewandte Chemie International Edition, which has been published in final form at https://doi.org/10.1002/anie.202502702. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.