期刊
JOURNAL OF MATERIALS CHEMISTRY A
卷 9, 期 6, 页码 3398-3408出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/d0ta10276h
关键词
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资金
- National Natural Science Foundation of China [51702217]
- Shenzhen Government's Plan of Science and Technology [JCYJ20190808121407676]
- Natural Science Foundation of Guangdong [2020A1515011127]
- Young Elite Scientists Sponsorship Program by CAST [2019QNRC001]
- Shenzhen University Initiative Research Program [2019005]
This study describes the synthesis of Co and N co-doped porous carbon nanospheres with efficient nitrogen retention and homogeneous dispersion of CoN4 sites, resulting in impressive electrocatalytic performance during oxygen reduction. The non-covalent interactions between cyclodextrin and p-phenylenediamine play a crucial role in optimizing nitrogen species mobility and retention, leading to a high nitrogen doping efficiency of approximately 57%. Density functional theory calculations suggest that CoN4 is the most active site among various sites considered.
Single atom catalysts (SACs) stabilized by nitrogen in a carbon support and having maximized atom utilization efficiency and an unsaturated environment exhibit high catalytic activity and selectivity. Incorporating nitrogen into the carbon lattice efficiently and uniformly is a critical step in preparing such catalysts but is challenging. The synthesis of Co and N co-doped porous carbon nanospheres (CoN-PCNS) in which Co is dispersed on the atomic scale is described herein, based on the facile pyrolysis of a mixture of cyclodextrin-based supermolecules with CoCl2. Non-covalent host-guest interactions between cyclodextrin and p-phenylenediamine in the supramolecular complex give optimal nitrogen species mobility and retention. These factors enable a thorough reaction between nitrogen and carbon during crosslinking to give ultrahigh nitrogen doping efficiency, with approximately 57% nitrogen retention upon pyrolysis and consequently a homogeneous dispersion of coordinated CoN4 sites throughout the carbon matrix. The CoN-PCNS exhibits impressive electrocatalytic activity during oxygen reduction, with an onset potential of 0.93 V, limiting current density of 5.74 mA cm(-2), good methanol tolerance and negligible activity decay under alkaline conditions after 10 000 voltage cycles. Density functional theory calculations suggest that CoN4 is the most active among the various sites.
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