Abstract
Academic interest in fuel cell technology is steadily increasing due to the demand for developing an affordable and effective biomass-derived catalyst for oxygen reduction reaction (ORR) to replace Pt-based catalysts. Nine groups of graphitic-N and pyridinic-N models are designed and analyzed using density functional theory (DFT). These results reveal that the ORR energy barriers for high-content graphitic-N models are only 0.10 eV and 0.11 eV, significantly lower than the 0.88 eV and 0.96 eV for pyridinic-N models, indicating that high-content graphitic-N structures are theoretically advantageous. High-protein seaweed is screened as a precursor to synthesize directionally high-content graphitic-N (3.56 at%) self-doped porous carbon ORR catalyst (S-850). The graphitic-N content of S-850 exceeds that of previously reported biomass-derived carbon-based ORR catalysts. Compared to 20% Pt/C (0.862 V and 5.60 mA cm− 2), S-850 (0.843 V and 5.24 mA cm− 2) exhibits only a 19 mV decrease in half-wave potential and a 0.36 mA cm− 2 decrease in limiting diffusion current density. S-850 also demonstrates superior stability and tolerance to methanol and CO compared to 20% Pt/C. Guided by DFT calculations, this study conducted the directional synthesis of high-performance, low-cost biomass-derived carbon-based ORR catalysts, offering a paradigm for future research.