Regulating the Electronic Synergy of Asymmetric Atomic Fe Sites with Adjacent Defects for Boosting Activity and Durability toward Oxygen Reduction

Abstract

The oxygen reduction reaction (ORR) plays a fundamental role in sustainable energy technologies. However, the creation of non‐precious metal electrocatalysts with high ORR activity and durability under all pH conditions is of great significance but remains challenging. Herein, the aim is to overcome this challenge by creating a Fe single atom catalyst on a 2D defect‐containing nitrogen‐doped carbon support (Fe1/DNC) via a microenvironment engineering strategy. Microkinetic modeling reveals that FeN4(OH) moieties are the real active sites under reaction conditions. Due to the synergistic promotion effect of denser accessible FeN4(OH) moieties and defect‐induced electronic properties, Fe1/DNC catalyst achieves extraordinary ORR activity under alkaline, acidic, and neutral conditions, with half‐wave potentials of 0.95, 0.82, and 0.70 V, respectively. Moreover, a negligible performance decay is observed with this Fe catalyst in stability and methanol tolerance tests. Zn‐air battery employing Fe1/DNC delivers remarkable peak power density and long‐term operational durability. Theoretical analysis provides compelling evidence that the defects adjacent to FeN4(OH) moieties can endow an inductive effect to reshape electronic properties to balance the OOH* formation and OH* reduction. This work offers insight into the regulation of asymmetric coordination structure and electronic properties of metal sites for boosting electrocatalytic activity and stability.

Hierarchical Porous Carbon Supported Co2P2O7 Nanoparticles for Oxygen Evolution and Oxygen Reduction in a Rechargeable Zn–Air Battery

“…Transition metals anchored on a hierarchical porous carbon matrix have been regarded as highly efficient electrocatalysts due to the merits of their easily tunable electron configuration and highly exposed active sites. − Typically, the d -block metal centers have been widely investigated for updating reduction activity via crystalline regulating, defect engineering, and metal elements tuning, due to their high surface-to-volume ratios and the presence of a multimetal atom structure. , In addition, the structure of the metal active centers can be modulated through heteroatom doping to enhance the catalytic activity and structural stability. − Furthermore, the morphology and nanoscale structure of the catalyst can be adjusted to anchor and expose metal sites at the gas/liquid/solid triphasic interface, − which facilitates the diffusion of gas molecules and the transport of O 2 to the active sites. − However, the intricate local coordination environment and the difficulty in precise structure design present a challenge in establishing effective bifunctional catalysts.…”