Chemical Vapor Deposition for Atomically Dispersed and Nitrogen Coordinated Single Metal Site Catalysts

• Published in: Angewandte Chemie International Edition Vol. 59; no. 48; pp. 21698 - 21705
• Main Authors: Liu, Shengwen, Wang, Maoyu, Yang, Xiaoxuan, Shi, Qiurong, Qiao, Zhi, Lucero, Marcos, Ma, Qing, More, Karren L., Cullen, David A., Feng, Zhenxing, Wu, Gang
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 23.11.2020
• Edition: International ed. in English
• Subjects: Catalysts; Chemical reactions; Chemical synthesis; Chemical vapor deposition; Dispersion; electrocatalysis; Electrochemistry; Electrolytes; Electrolytic cells; Fe-N-C; Fuel technology; Iron; Manganese; Metals; Nickel; Nitrogen; oxygen reduction reaction; Platinum; Proton exchange membrane fuel cells; single metal sites; Substrates; Vapors; Zinc oxide
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202009331

Atomically dispersed and nitrogen coordinated single metal sites (M‐N‐C, M=Fe, Co, Ni, Mn) are the popular platinum group‐metal (PGM)‐free catalysts for many electrochemical reactions. Traditional wet‐chemistry catalyst synthesis often requires complex procedures with unsatisfied reproducibility and scalability. Here, we report a facile chemical vapor deposition (CVD) strategy to synthesize the promising M‐N‐C catalysts. The deposition of gaseous 2‐methylimidazole onto M‐doped ZnO substrates, followed by an in situ thermal activation, effectively generated single metal sites well dispersed into porous carbon. In particular, an optimal CVD‐derived Fe‐N‐C catalyst exclusively contains atomically dispersed FeN4 sites with increased Fe loading relative to other catalysts from wet‐chemistry synthesis. The catalyst exhibited outstanding oxygen‐reduction activity in acidic electrolytes, which was further studied in proton‐exchange membrane fuel cells with encouraging performance. Atomically dispersed and nitrogen coordinated iron (Fe‐N‐C) catalysts are prepared by using chemical vapor deposition. The catalysts exhibit outstanding oxygen‐reduction activity in acidic electrolytes, which can further transfer into membrane electrode assemblies (MEAs) for fuel cell applications. The MEAs are capable of generating current densities of 27 mA cm−2 at 0.9 V (1.0 bar O2) and 117 mA cm−2 at 0.8 V (1.0 bar air).