Bifunctional Edge‐Rich Nitrogen Doped Porous Carbon for Activating Oxygen and Sulfur

Abstract

Oxygen reduction reaction (ORR) and sulfur reduction reaction (SRR) play key roles in advanced batteries. However, they both suffer from sluggish reaction kinetics. Here, an interesting nitrogen doped porous carbon material that can simultaneously activate oxygen and sulfur is reported. The carbon precursor is a nitrogen containing covalent organic framework (COF), constituting periodically stacked 2D sheets. The COF structure is well preserved upon pyrolysis, resulting in the formation of edge-rich porous carbon with structure resembling stacked holey graphene. The nitrogen containing groups in the COF are decomposed into graphitic and pyridinic nitrogen during pyrolysis. These edge sites and uniform nitrogen doping endow the carbon product with high intrinsic catalytic activities toward ORR and SRR. The COF derived carbon delivers outstanding performances when assembling as cathodes in the Li-S and Li-O 2 batteries. Simultaneous activation of oxygen and sulfur also enables a new battery chemistry. A proof-of-concept Li-S/O 2 hybrid battery is assembled, delivering a large specific capacity of 2,013 mAh g −1 . This study may inspire novel battery designs based on oxygen and sulfur chemistry.

High-dispersion Co/N/C ultra-thin carbon nanosheets modified with trace Ce as efficient oxygen reduction reaction catalysts

“…Besides the total content of N doping, the bonding type of N doping also influences the activity of the catalysts. 50 To analyze the influence of different N atom types on ORR catalytic activity, the content of different types of nitrogen in the Ce-Co/N/C and Co/N/C catalysts was compared. As can be seen from Table S3 (ESI †), graphite-N (38.83%) and pyridine-N (26.49%) occupied the dominant proportion of the N conformation.…”

“…Besides the total content of N doping, the bonding type of N doping also influences the activity of the catalysts. 50…”

Optimization Strategies of Covalent Organic Frameworks and Their Derivatives for Electrocatalytic Applications

“…Liu et al pyrolyzed COF with abundant micropores and mesopores to prepare carbon materials with rich carbon edges (COF x , x: temperature). [212] After pyrolysis, COF 800 well inherited the morphology and structure of the precursor, and there were abundant pores on its surface. Differently, the carbon sheets composed of curved graphite layers had sharp edges, confirming the generation of carbon edges.…”

Advanced nano-bifunctional electrocatalysts in Li–air batteries for high coulombic efficiency

“…The green and low-cost CB-H catalyst promoted a higher discharge capacity of 18 578 mA h g −1 at 50 mA g −1 than that of other reported commercial carbon materials. To this day, this modification strategy is revered and explored by most for developing efficient bifunctional carbon-based catalysts, such as P-doped hive-like porous carbon, 160 sawdust-derived porous carbon, 161 edge-rich N doping porous carbon, 162 and so on.…”