High-content graphitic-N self-doped porous carbon catalyst derived from seaweed for efficient oxygen reduction reaction
摘要
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.