Shankui Luan¹, Jing Liu^1*, Shengchang Li¹, Shuo Li¹, Zhangrong Lou², Mingyue Lv¹, Xuejing Cui¹, Luhua Jiang^1*

¹College of Materials Science & Engineering, Qingdao University of Science & Technology, Qingdao, 266042, P.R. China

²Dalian University of Technology, Dalian, 116024, P.R. China

*Corresponding authors: liuj955@qust.edu.cn; luhuajiang@qust.edu.cn

Abstract

Developing low-Pt catalysts for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFC) remains a significant challenge due to the stringent demands on both high power density and long-term durability. Guided by theoretical calculations, we identify Co-NC as the most prospective transition metal and nitrogen-doped carbon (M-NC) support. Co-NC exhibits the strongest interaction with Pt, lowering the energy level of the Pt d-band, which enhances both stability and activity. Furthermore, the ordered Pt₃Co/Co-NC catalyst achieves a mass activity (MA) of 0.76 A mg_Pt^-1 at 0.9 V_iR-free vs. RHE, with a loss of only 12 mV in half-wave potential after 30k cycles of  accelerated degradation test (ADT). The membrane electrode assembly (MEA) composed of Pt₃Co/Co-NC cathode delivers excellent performance exceeding the DOE 2025 target, with MA is 0.66 A mg_Pt^-1 at a cell voltage of 0.9 V, and 74.8% of the initial performance was retained after 30k ADT cycles. Experimental and theoretical investigations, combining in situ surface-enhanced infrared spectroscopy reveal that the *OOH intermediates are stabilized at the Co-NC active sites, while *OH adsorption on the Pt sites in Pt₃Co is weakened, leading to optimal adsorption of oxygen-containing intermediates on dual active sites, and effectively addresses the limitations associated with single active sites. This work sheds light on the synergistic effect of the different M-NC and Pt nanoparticles, paving the way for designing highly active and stable catalysts for PEMFC applications.

Keywords: metal-support interaction, oxygen reduction reaction, fuel cell, metal nitrogen-doped carbon, intermetallic

https://doi.org/10.1016/j.cej.2024.158666