Affiliation:
1. Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 P. R. China
2. Department of Chemistry National University of Singapore Singapore 117543 Singapore
3. School of Materials Science and Engineering Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin University Tianjin 300072 P. R. China
4. Department of Chemical and Biomolecular Engineering National University of Singapore Singapore 117585 Singapore
Abstract
AbstractAtomically dispersed metal‐nitrogen‐carbon catalysts have been extensively explored for various sustainable energy‐related reactions. From a material perspective, these catalysts are likely to consist of a combination of single‐atom, dual‐atom and possibly even multi‐atom sites. However, pinpointing their true active sites has remained a challenging task. In this study, a model catalyst is introduced, Co/CoMn‐NC, featuring both Co single‐atom sites and CoMn dual‐atom sites on a nitrogen‐doped carbon substrate. By employing a combination of X‐ray adsorption spectroscopy and density functional theory calculations, the atomic configuration of Co/CoMn‐NC has been determined. Density functional theory calculations are also used to unequivocally identify Co‐atom within the CoMn dual‐atom motif as the predominate active site of the Co/CoMn‐NC model catalyst toward oxygen reduction reaction (ORR), which is further confirmed by in situ Raman spectroscopy. The cooperative interactions between Co single‐atom sites and CoMn dual‐atom sites can finely tune the d‐band center and ameliorate the adsorption and desorption behaviors of the intermediates, thereby facilitating ORR kinetic. Overall, the study introduces a systematic strategy to elucidate the structure and the superiority of the model system and provides new insights into atomically dispersed multi‐metal active sites, showcasing that enhanced catalytic performance extends beyond unified diatomic sites or monatomic sites.
Funder
National Natural Science Foundation of China
Subject
Electrochemistry,Condensed Matter Physics,Biomaterials,Electronic, Optical and Magnetic Materials