Etching-time-regulated strategy toward delaminated Mo 2CT x MXene for tailoring electromagnetic wave absorption

MXene-based absorbers have shown promising application prospects because of their sophisticated structural design and clever material composites. However, the intrinsic MXene materials themselves have not achieved significant breakthroughs in microwave absorption (MA) performance. Therefore, the development of novel and efficient pure MXene absorbing materials is imperative to address inherent mismatches in electromagnetic parameters, highlighting the urgent need in this area. Here, a straightforward strategy involving etching time modulation is proposed to customize the electromagnetic wave (EMW) absorption properties of delaminated Mo₂CT_x MXene. The impact of varying etching degrees on the EMW absorption capabilities of Mo₂CT_x MXenes was systematically investigated through controlled etching durations of Mo₂Ga₂C MAX phase. Among them, the sample etched for 12 h achieved an effective absorption bandwidth (EAB) of 4.4 GHz at an ultrathin thickness of 1.3 mm, and the strongest reflection loss (RL) value was as high as −60.7 dB when the sample etching time was increased to 24 h. The improvement in absorbing performance was attributed to the dielectric loss and polarization process induced by terminal functional groups and surface-rich defects, which optimized impedance matching. This work establishes that intrinsic Mo₂CT_x MXene materials with superior absorbing properties outperform traditional pure MXenes, providing a strong basis for advancing Mo-based MXene absorptive materials.