Regulating the Oxygen Affinity of Single Atom Catalysts by Dual-atom Design for Enhanced Oxygen Reduction Reaction Activity
Meng Zheng , Jin Wang
Chemical Research in Chinese Universities ›› 2022, Vol. 38 ›› Issue (5) : 1275 -1281.
Regulating the Oxygen Affinity of Single Atom Catalysts by Dual-atom Design for Enhanced Oxygen Reduction Reaction Activity
This work chooses Cu/Fe single-atom catalysts(SACs) with weak/strong oxygen affinity to clarify the effect of dual-atom configuration on oxygen reduction reaction(ORR) performance based on density functional theory(DFT) calculations. The stability and ORR activity of single or dual Cu/Fe atomic sites anchored on nitrogen-doped graphene sheets(Cu-N4-C, Cu2-N6-C, Fe-N4-C, and Fe2-N6-C) are investigated, and the results indicate the dual-atom catalysts(Cu2-N6-C and Fe2-N6-C) are thermodynamically stable enough to avoid sintering and aggregation. Compared with single-atom active sites of Cu-N4-C, which show weak oxygen affinity and poor ORR performance with a limiting potential of 0.58 V, the dual-Cu active sites of Cu2-N6-C exhibit enhanced ORR activity with a limiting potential up to 0.87 V due to strengthened oxygen affinity. Interestingly, for Fe SACs with strong oxygen affinity, the DFT results show that the dual-Fe sites stabilize the two OH* ligands structure[Fe2(OH)2-N6-C], which act as the active sites during ORR process, resulting in greatly improved ORR performance with a limiting potential of 0.90 V. This study suggests that the dual-atom design is a potential strategy to improve the ORR performance of SACs, in which the activity of the single atom active sites is limited with weak or strong oxygen affinity.
Single-atom catalyst / Dual-atom / Oxygen reduction reaction(ORR) / Oxygen affinity / Density functional theory(DFT)
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