Spatial Heteroatom Modulates Electron Itinerancy of Spinel Lattice for Accelerated Oxygen Catalysis
Heteroatom occupancy is pivotal for modulating specific material regions by introducing foreign elements into the host matrix, yet its spatial dimension remains underexplored. We introduce a 'satellite atom-spinel crystal' concept by synthesizing model catalysts with Fe atoms positioned at two distinct spatial locations of spinel Co3O4: satellite-Fe at Co3O4 (Fe(Sat)-Co3O4) and Fe-doped Co3O4 (Co3Fe(In)O4). Multidimensional in situ spectroscopies reveal that Fe(Sat)-Co3O4 overcomes the crystal field potential energy (FeSat–O > FeSat–O–CoOh) and exhibits 1% (Fe atom) lower impedance than Co3Fe(In)O4 due to a resistance-free electron delocalization layer formed in Fe(Sat)-Co3O4. This results in tens of times increase in turnover frequency and mass activity, and a 120 mV reduction in overpotential for the electrochemical oxygen evolution reaction compared to Co3Fe(In)O4. Density functional theory calculations dynamically elucidate the mechanisms governing electron itinerancy modulation. This study provides valuable insights into the impact of heteroatomic spatial positioning on material properties and significantly expands our understanding of atomic manipulation.