The primary challenge in rechargeable Zn-air batteries lies in developing a catalyst capable of simultaneously improving performance for oxygen reduction reaction(ORR)during discharge and oxygen evolution reaction(OER...The primary challenge in rechargeable Zn-air batteries lies in developing a catalyst capable of simultaneously improving performance for oxygen reduction reaction(ORR)during discharge and oxygen evolution reaction(OER)during charge.Engineering spin configuration is essential for enhancing the intrinsic bifunctional activity and stability of spinel Co_(3)O_(4).Herein,Cr^(3+)is doped into Co_(3)O_(4),inducing directional distortion of CoO_6 octahedron to modify crystal field splitting energy,pushing Co_(Oh)toward intermediate-spin(IS)configuration(t_(2g)^(5)e_(g^(1)))with optimized eg occupancy of 1.04.As a result,9%Cr-Co_(3)O_(4)demonstrates an excellent bifunctional activity and remarkable rechargeable Zn-air battery performance that even outperforms Pt/C+RuO_(2).Density functional theory(DFT)studies reveal that IS Co_(Oh)not only regulates the adsorption energy of ORR/OER species but also transform the O_(2)adsorption configuration from end-on to Griffith configuration,thus modifies the mechanisms of both ORR and OER process and optimize bifunctional activity and selectivity.This work provides mechanistic insight into the spin origin of ORR/OER catalysis and highlights a promising strategy for developing robust bifunctional electrocatalysts.展开更多
基金supported by the National Natural Science Foundation of China(No.22179032,51871088,51771068,52171176)the Natural Science Foundation of Hebei Province(No.B2021202011)。
文摘The primary challenge in rechargeable Zn-air batteries lies in developing a catalyst capable of simultaneously improving performance for oxygen reduction reaction(ORR)during discharge and oxygen evolution reaction(OER)during charge.Engineering spin configuration is essential for enhancing the intrinsic bifunctional activity and stability of spinel Co_(3)O_(4).Herein,Cr^(3+)is doped into Co_(3)O_(4),inducing directional distortion of CoO_6 octahedron to modify crystal field splitting energy,pushing Co_(Oh)toward intermediate-spin(IS)configuration(t_(2g)^(5)e_(g^(1)))with optimized eg occupancy of 1.04.As a result,9%Cr-Co_(3)O_(4)demonstrates an excellent bifunctional activity and remarkable rechargeable Zn-air battery performance that even outperforms Pt/C+RuO_(2).Density functional theory(DFT)studies reveal that IS Co_(Oh)not only regulates the adsorption energy of ORR/OER species but also transform the O_(2)adsorption configuration from end-on to Griffith configuration,thus modifies the mechanisms of both ORR and OER process and optimize bifunctional activity and selectivity.This work provides mechanistic insight into the spin origin of ORR/OER catalysis and highlights a promising strategy for developing robust bifunctional electrocatalysts.
