Impact of Carbon N‑Doping and Pyridinic‑N Content on the Fuel Cell Performance and Durability of Carbon-Supported Pt Nanoparticle Catalysts

• Published in: ACS applied materials & interfaces Vol. 14; no. 16; pp. 18420 - 18430
• Main Authors: Hornberger, Elisabeth, Merzdorf, Thomas, Schmies, Henrike, Hübner, Jessica, Klingenhof, Malte, Gernert, Ulrich, Kroschel, Matthias, Anke, Björn, Lerch, Martin, Schmidt, Johannes, Thomas, Arne, Chattot, Raphaël, Martens, Isaac, Drnec, Jakub, Strasser, Peter
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.04.2022; Washington, D.C. : American Chemical Society
• Subjects: carbon; catalysts; cathodes; Chemical Sciences; corrosion; durability; electrochemistry; Energy, Environmental, and Catalysis Applications; fluidized beds; fuel cells; liquids; platinum; X-ray diffraction; MEA; electrocatalyst; fuel cell; N-doped carbon; oxygen reduction reaction; operando HE-XRD
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.2c00762

Cathode catalyst layers of proton exchange membrane fuel cells (PEMFCs) typically consist of carbon-supported platinum catalysts with varying weight ratios of proton-conducting ionomers. N-Doping of carbon support materials is proposed to enhance the performance and durability of the cathode layer under operating conditions in a PEMFC. However, a detailed understanding of the contributing N-moieties is missing. Here, we report the successful synthesis and fuel cell implementation of Pt electrocatalysts supported on N-doped carbons, with a focus on the analysis of the N-induced effect on catalyst performance and durability. A customized fluidized bed reduction reactor was used to synthesize highly monodisperse Pt nanoparticles deposited on N-doped carbons (N–C), the catalytic oxygen reduction reaction activity and stability of which matched those of state-of-the-art PEMFC catalysts. Operando high-energy X-ray diffraction experiments were conducted using a fourth generation storage ring; the light of extreme brilliance and coherence allows investigating the impact of N-doping on the degradation behavior of the Pt/N–C catalysts. Tests in liquid electrolytes were compared with tests in membrane electrode assemblies in single-cell PEMFCs. Our analysis refines earlier views on the subject of N-doped carbon catalyst supports: it provides evidence that heteroatom doping and thus the incorporation of defects into the carbon backbone do not mitigate the carbon corrosion during high-potential cycling (1–1.5 V) and, however, can promote the cell performance under usual PEMFC operating conditions (0.6–0.9 V).