Etching-time-regulated strategy toward delaminated Mo₂CT_x MXene for tailoring electromagnetic wave absorption

MXene-based absorbers have shown promising application prospects due to 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 absorption properties of delaminated Mo₂CT_x MXene. The impact of varying etching degrees on the electromagnetic wave absorption capabilities of Mo₂CT_x MXene 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 ultra-thin thickness of 1.3 mm, and the strongest reflection loss (RL) value is as high as -60.7 dB when the sample etching time is increased to 24 h. The improvement in absorbing performance is attributed to the dielectric loss and polarization process induced by terminal functional groups and surface-rich defects, optimizing impedance matching. This work establishes that intrinsic Mo₂CT_x MXene materials with superior absorbing properties outperform traditional pure MXene, providing a strong basis for advancing Mo-based MXene absorptive materials.