Ce-4f/N double-doped Mo-MXene for regulating dielectric polarization response

Ti₃C₂T_x MXene, with its mature preparation process and excellent conductivity, holds an important position in the field of electromagnetic wave absorption. However, as the performance requirements for electromagnetic wave absorbing materials in civilian and defense fields continue to upgrade, traditional Ti₃C₂T_x MXene is gradually becoming less capable of meeting the more stringent application demands. Against this backdrop, the novel bimetallic Mo₂TiC₂ MXene (Mo-MXene) has gradually emerged in the field of electromagnetic wave absorption. This new material not only retains the inherent advantages of traditional Ti₃C₂T_x MXene but also benefits from its unique alternating arrangement structure of Mo-4d outer atoms and Ti intermediate atoms, which facilitates the in-situ formation of Mo-based compounds on the surface to effectively construct hetero-interfaces and enhance polarization effects. It is worth noting that the material still suffers from impedance mismatch caused by its high electrical conductivity. Therefore, selecting appropriate regulation methods to improve the dielectric properties of Mo-MXene is a significant challenge.

To address the issue of a single-loss mechanism in MXene materials, Prof. Zeng Xiaojun's team from Jingdezhen Ceramic University has developed a novel Mo-MXene/MoO₂-N/Ce composite system. By employing a co-doping strategy of non-metallic N and rare-earth metal Ce-4f in Mo-MXene, precise regulation of dielectric loss has been achieved. Specifically, the Mo-MXene prepared through an etching process contains vacancies and surface functional groups that can effectively capture Ce ions. Meanwhile, the oxygen in Ce salts and functional groups can induce in-situ oxidation of Mo elements during heat treatment process, forming a heterostructure and enhancing interfacial polarization capability. On one hand, the introduction of Ce can promote hybridization between the Ce-4f orbitals of the rare-earth element and the Mo-4d orbitals, altering the electronic structure of Ce and Mo-MXene, facilitating charge migration, thereby enhancing polarization loss. On the other hand, incorporating melamine into the precursor can induce N doping in Mo-MXene, promoting dipolar polarization. At a frequency of 13.43 GHz and a matching thickness of 4.685 mm, the optimal reflection loss of Mo-MXene/MoO₂-N/Ce reaches -57.46 dB, which is superior to many reported MXene-based absorbing materials.

The team published their review in Nano Research on June 6, 2025.

“This research confirms that Mo-MXene/MoO₂-N/Ce is a promising EMW absorption material and provides valuable insights into modulating MXene-based EMW absorbers using rare earth elements. Future research will focus on developing diversified strategies for constructing Mo-MXene heterostructures, with an emphasis on systematically elucidating the electromagnetic loss mechanisms of MXene-based electromagnetic wave absorbing materials, providing theoretical support for the development of the next generation of high-performance electromagnetic wave absorbing materials.” Zeng Xiaojun from the School of Materials Science and Engineering at Jingdezhen Ceramic University said.

Other contributors include Yunan Tan and ShenAo Cheng from Jingdezhen Ceramic University, Jingdezhen, China.

This work was supported by the National Natural Science Foundation of China (No. 22269010), the Jiangxi Provincial Natural Science Foundation (No. 20224BAB214021, S2024ZRZDL0583), and the Major Research Program of Jingdezhen Ceramic Industry (No. 2023ZDGG002).

About the Authors

Dr. Xiaojun Zeng is currently a professor at the School of Materials Science and Engineering, Jingdezhen Ceramic University. He is a postdoctoral fellow at the University of California, Santa Barbara (UCSB) under the supervision of Prof. Galen D. Stucky. He obtained his Ph.D. degree in Materials Physics and Chemistry from Beihang University (BUAA) in 2019. From 2017 to 2019, he carried out research under the supervision of Prof. Yadong Yin at the University of California, Riverside (UCR). His current research interests focus on the development of advanced nanomaterials for electromagnetic functional materials and energy catalytic materials.

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.