Engineering rich defects in nitrogen-doped porous carbon to boost oxygen reduction reaction kinetics

Metal-free carbon-based materials offer a promising alternative to Pt-based catalysts for the oxygen reduction reaction (ORR). However, challenges persist due to its sluggish kinetics and poor acid ORR performance. Here, we introduce a novel nitrogen-doped porous carbon with rich defects sites (such as pentagons, edge and vacancy defects) (PV/HPC) via a simple etching strategy. The PV/HPC demonstrates long-term stability and exceptional catalytic activity with half-wave potential of 0.9 V and average electron transfer number of 3.98 in alkaline solution while 0.78 V and 3.78 in acidic solution, indicating its efficiency and robustness as an ORR catalyst. Additionally, it achieves a higher kinetic current density of 91.9 mA cm-2 at 0.8 V, which is 1.75 times that of Pt/C (52.5 mA cm-2). Furthemore, it enables Al-air battery to attain a maximum power density of 487 mW cm-2, compared to 477 mW cm-2 for the Pt/C catalyst. Density functional theory (DFT) calculations elucidate that the introduction of multifunctional defects in nitrogen-doped porous carbon collectively reduces the reaction energy barrier of the departure of OH* and boosts the oxygen reduction reaction kinetics. This work presents a simple method to design durable and effective carbon-based ORR catalysts. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.