Oxygen vacancy boosted microwave absorption in CeO2 hollow nanospheres
Xinxin Wang, Kang Fu, Xiaoyi Wen, Shi‐Chao Qi, Guoxiu Tong, Xiaojuan Wang, Wenhua Wu, Xiaojuan Wang, Wenhua Wu
Abstract
Oxygen vacancy engineering is one of the key strategies to modulate the electric structure and properties of metal oxides. However, the relationship between oxygen vacancies and electromagnetic wave (EMW) absorption capabilities is so far unclear. Herein, oxygen vacancy boosted microwave absorption was realized over CeO 2 dual-shell hollow nanospheres (HNSs), which can be tuned by thermal conversion temperatures ( T s ) of CeOHCO 3 HNSs. The lattice stress decreases linearly, and the conductivity increases gradually with the elevating T s . Our findings show that a moderate T s favors the formation of dual-shell CeO 2 HNSs with a high oxygen vacancy concentration, a large S BET , an appropriate lattice defect, and proper conductivity. The abundant oxygen vacancies endow CeO 2 HNSs with massive localized electrons and dipole centers, which benefit the conductivity, conductive loss, defect/dipole polarizations. CeO 2 DSHNSs formed at T s = 400 °C bear broad bandwidth (5.44 GHz) and strong absorption (−43.28 dB), far superior to the reported CeOHCO 3 single-shell HNSs, CeO 2 single-shell HNSs, and most other CeO 2 -based composites. Overall, this work establishes a clear correlation between oxygen vacancy defects and EMW dissipation ability, offering valuable insights for designing superior EMW absorbents.