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We propose a polyoxometalate pre-confined strategy combined with density functional theory (DFT) screening to prepare a diatomic pair catalyst (DPC) of β- (3, 8) -FeCoSiW 10 @N-C. A H 4 SiW 12 O 40 polyoxometalate was selected as the confining platform to precisely regulate the Fe Co distance in DPCs. The replacement of two W O groups with FeO/CoO on specific positions of H 4 SiW 12 O 40 produced five isomers with different Fe Co distances, based on which five corresponding DFT models were constructed. DFT calculations indicate that the most favorable oxygen reduction reaction (ORR) energies were obtained by the DPC derived from the β- (3, 8) -FeCoSiW 10 O 36 isomer with a Fe Co distance of 3. 031 Å. At this DPC, O 2 molecules preferred to adsorb on adjacent Fe Co diatomic pairs via a Bridge adsorption mode. Therefore, the ORR by-passed the O 2 → *OOH step with slow kinetics to achieve direct O O bond cleavage requiring less reaction energy. The DPC on a carbon substrate obtained an ORR half-wave potential of 0. 856 V in neutral electrolyte, while Zn-air batteries with a DPC cathode showed a high power density of 204. 8 mW cm −2 and stability of ~300 h. This work provides an effective strategy to synthesize high-efficiency DPCs for future energy devices. • Polyoxometalate pre-confined strategy is used to prepare Fe Co diatomic pair catalyst. • Fe Co distance of 3. 031 Å in diatomic pair facilitate adsorption of O 2 via Bridge mode. • The optimum catalyst exhibits superior OER/ORR performance in neutral electrolyte. • Coin cells with the optimum catalyst cathode shows high power density and stability.
Niu et al. (Sun,) studied this question.