Synthesis of a new graphene-like transition metal carbide by de-intercalating Ti3AlC2

Recent advances in MXene: Preparation, properties, and applications

“…Notably, the etching conditions (time and HF concentration) necessary to convert a given MAX phase vary widely, depending on the particle size and temperature. For example, reducing the MAX phase particle size by attrition or ball milling can effectively reduce the necessary etching time and/or HF concentration [14,25]. In addition, discrepancies in M-Al bond energies for different MAX phases also require different etching conditions.…”

Microstructure and phase transformation of Ti3AC2 (A = Al, Si) in hydrofluoric acid solution

“…Ti 3 AlC 2 has poor resistance to 40% HF solution at room temperature, and Al layers are selectively etched off after immersion just 4h due to the more active Ti-Al bond compared with strong covalent bond of Ti-C. And the 2D graphene-like structure is obtained after being etched for 20h in HF solution and remains stable as reaction time elongates in our previous study [17]. However, the morphology transition in hydrothermal environment is quite different from that at room temperature.…”

“…All the www.crt-journal.org diffraction peaks of Ti 3 AlC 2 disappear after just an hour etching treatment in HF solution and accordingly are replaced by broad peaks corresponding to those of TiC x which are reported a cubic rock-salt phase generated from the topotactic transformation of hexagonal structure by selective etching of Al layers from Ti 2 AlC [21]. This means that the Ti-C layers after the removal of Al layers from Ti 3 AlC 2 under a high temperature condition are to occur with atomic rearrangements, while in our previous work the lattice plane still keep hexagonal symmetric when Ti 3 AlC 2 is treated in HF solution at room temperature [17]. Moreover, figure 3 gives the TEM micrographs of Ti 3 AlC 2 after hydrothermal treatment in HF solution at 180°C for an hour, which well confirms that the 2-D TiC x sheet is cubic phase.…”

“…The Ti 3 AlC 2 powder used in this work was obtained by pressureless argon shielding synthesis technique, and the preparing procedure was detailed elsewhere [17]. In this study, the specific molar ratio of Ti, Al, graphite powders was 3:1.1:1.9 (the content of Al exceeded the stoichiometry, which not only supplemented the loss of Al because of evaporation at high temperature, but also favored the formation of the molten pool to promote the rate of reaction during the process of sintering [18,19]).…”

“…The microstructure and phase transformation of Ti 3 AlC 2 in HF solution at room temperature have been investigated detailedly in our previous study [17], in which the two-dimension Ti-C layers are obtained because the Al layers are removed fromTi 3 AlC 2 . And the etching direction is parallel to (0001) plane.…”