Defect Engineering of Mo Single‐Atoms and Confinement of Mo Clusters in Porous Carbon Nanoflowers for Efficient Electromagnetic Wave Absorption

ABSTRACT Metal single‐atom‐based materials exhibit remarkable electromagnetic wave absorption capabilities; however, the role of local microstructures, particularly defect‐induced symmetry‐broken configurations, remains insufficiently understood. Herein, Mo single‐atoms with a symmetry‐broken Mo–N 3 coordination environment are engineered within carbon nanoflowers to clarify the influence of the local microstructure of Mo species on dielectric behavior and electromagnetic wave absorption performance. For comparison, Mo‐containing clusters and Mo x O y nanoparticles are also introduced into the carbon nanoflowers. Theoretical calculations demonstrate that defect‐containing Mo–N 3 sites possess superior dielectric properties relative to conventional Mo–N 4 configurations, owing to the asymmetric charge distribution induced by carbon defects in the first coordination shell. Experimental results reveal that the Mo–N 3 configuration within carbon nanoflowers shows superior electromagnetic wave absorption performance with an effective absorption bandwidth of 5.31 GHz at a thickness of 2.0 mm. In addition, it is also found that Mo‐containing clusters facilitate the reflection loss value, while symmetry‐broken Mo–N 3 sites can expand the effective absorption bandwidth at a thinner thickness. These results demonstrate that tailoring local environments of Mo single‐atoms and construction of clusters are promising strategies for optimizing the electromagnetic wave absorption property of an absorber.