Simultaneously tuning structural defects and crystal phase in accordion-like Ti <sub> <i>x</i> </sub>O <sub>2 <i>x</i>−1 </sub> derived from Ti <sub>3</sub>C <sub>2</sub>T <sub> <i>x</i> </sub> MXene for enhanced electromagnetic attenuation
Yang Li, Yuchang Qing, Yuerui Zhang, Hailong Xu
Abstract
The single Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene material is not suitable for electromagnetic (EM) wave absorption due to its high conductivity and impedance mismatch. To address this issue, we ingeniously take advantage of easily oxidized characteristic of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene to establish structural defects and multiphase engineering in accordion-like Ti<em><sub>x</sub></em>O<em><sub>2x-1</sub></em> derived from Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene by the high-temperature hydrogen reduction process in the first time. The phase evolution sequences are revealed to be Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene/anatase TiO<sub>2</sub> → Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene/rutile TiO<sub>2</sub> → Ti<em><sub>x</sub></em>O<em><sub>2x-1</sub></em> (1≤<em>x</em>≤4) during the hydrogen reduction reaction. Benefiting from the conductance loss caused by hole motion under the action of external electric field and heterointerfaces caused interfacial polarization, the impedance match and EM attenuation capability of accordion-like Ti<em><sub>x</sub></em>O<em><sub>2x-1</sub></em> absorbers derived from Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene are superior to that of pristine Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene/TiO<sub>2 </sub>material. Additionally, the simulated whole radar cross section (RCS) plots in the different incident angular of Ti<sub>3</sub>C<sub>2</sub>T<sub>x</sub> MXene/rutile TiO<sub>2</sub> product is lower than -20 dBm<sup>2</sup> and the minimum RCS value can reach -43 dBm<sup>2</sup>, implying a great potential for practical application in the EM wave absorption. Moreover, the relationship between charges, defects, interfaces, EM performances in accordion-like Ti<em><sub>x</sub></em>O<em><sub>2x-1</sub></em> materials is systematically clarified by energy band theory, which is suitable for the research of other MXene-derived semiconductor absorbing composites.