As an outstanding representative of two-dimensional materials, newly emerged Ti₃C₂T_x MXene has aroused widespread attention in the field of microwave absorption (MA). However, the high conductivity of Ti₃C₂T_x MXene is prone to lead to impedance mismatch, and the attenuation performance of incident electromagnetic waves in the Ti₃C₂T_x matrix needs to be further improved. To address these issues, Ti₃C₂T_x MXene quantum dots (MQDs) were applied in the field of MA for the first time, and combined with Ti₃C₂T_x derivative chrysanthemum-like Na₂Ti₃O₇ to prepare Na₂Ti₃O₇/MQDs composites with 3D/0D heterostructure. Compared with Ti₃C₂T_x MXene bulks and nanosheets, Ti₃C₂T_x MQDs possess larger specific surface area and richer surface-active groups and defects, which are more favorable for interfacial polarization and dipole polarization, while the moderate conductivity of Ti₃C₂T_x MQDs is conducive to impedance matching. The unique chrysanthemum-like Na₂Ti₃O₇/MQDs with 3D/0D heterostructure generates abundant heterointerfaces to promote the increase of interfacial polarization, achieves a rational combination of different conductive materials to optimize impedance matching, and facilitates multiple reflections of electromagnetic waves among numerous nanowires in the chrysanthemum-like structure. Benefiting from the good impedance matching and the synergistic effect of multiple loss mechanisms, Na₂Ti₃O₇/MQDs composites show excellent MA performance with a minimum reflection loss of −48.28 dB at a thickness of 2.6 mm. Simultaneously, the effective absorption bandwidth comes up to 6.38 GHz at 2.5 mm thickness. This study demonstrates the potential of MQDs as efficient microwave absorbers and points out the direction for a wide application of various MQDs in the field of MA.

作为二维材料的杰出代表，新出现的Ti ₃ C ₂ T _x MXene在微波吸收（MA）领域引起了广泛关注。然而，Ti ₃ C ₂ T _{x MXene的高导电性容易导致阻抗失配，Ti 3} C ₂ T _x基体对入射电磁波的衰减性能有待进一步提高。针对这些问题，Ti ₃ C ₂ T _x MXene量子点（MQDs）首次应用于MA领域，并与Ti ₃ C相结合₂ T _x衍生物类菊Na ₂ Ti ₃ O ₇制备具有3D/0D异质结构的Na ₂ Ti ₃ O ₇ /MQDs复合材料。与Ti ₃ C ₂ T _x MXene块体和纳米片相比，Ti ₃ C ₂ T _x MQDs具有更大的比表面积和更丰富的表面活性基团和缺陷，更有利于界面极化和偶极极化，同时具有适中的电导率Ti ₃ C ₂ T _xMQDs有利于阻抗匹配。独特的菊花状Na ₂ Ti ₃ O ₇ /MQDs具有3D/0D异质结构，产生丰富的异质界面促进界面极化增加，实现不同导电材料的合理组合优化阻抗匹配，促进电磁波在材料间的多次反射菊花状结构中的许多纳米线。得益于良好的阻抗匹配和多种损耗机制的协同作用，Na ₂ Ti ₃ O ₇/MQDs 复合材料表现出出色的 MA 性能，在 2.6 mm 的厚度下具有最低 −48.28 dB 的反射损耗。同时，有效吸收带宽在 2.5 mm 厚度时达到 6.38 GHz。该研究展示了 MQD 作为高效微波吸收器的潜力，并为各种 MQD 在 MA 领域的广泛应用指明了方向。