Nitrogen-Doped Ti3C2Tx MXene Induced by Plasma Treatment with Enhanced Microwave Absorption Properties

Ti3C2Tx has microwave absorption (MA) properties due to its dielectric loss, but the absence of magnetic loss capability of pure Ti3C2Tx causes unmatched impedance and unsatisfied MA performance. Modification of Ti3C2Tx with magnetic particles is an effective way to introduce the magnetic loss mechanism. However, these modified Ti3C2Tx particles have higher density and require complicated fabrication processes, restricting the industrial production and functional applications. Here, a low-temperature and simple method of radio-frequency N2 plasma treatment was adopted to modify Ti3C2Tx with N. More interestingly, the N-doped Ti3C2Tx flakes demonstrated magnetic properties and thus exhibited drastically enhanced MA properties. The minimum reflection loss (RLmin) of -59.20 dB at 10.56 GHz was achieved in N-doped Ti3C2Tx products after only 3 min of plasma treatment, remarkably higher than RLmin of -11.07 dB at 7.92 GHz for the pristine Ti3C2Tx. The main mechanism is due to the combination of dielectric loss, magnetic loss, and the good impedance matching in the N-doped Ti3C2Tx. Further prolonging the nitriding time induces much desorption of -F and the formation of TiO2, thus deteriorating the impedance matching and the MA properties.