Exfoliation behavior and superior photothermal conversion performance of MXenes beyond Ti3C2Tx

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 472
• Main Authors: Wen, Cuilian, Liao, Qiugang, Cui, Zhou, Chen, Ziqiang, Liu, Hao, Xiong, Rui, Sa, Baisheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-09-2023
• Subjects: Density functional theory; Exfoliation behavior; MAX phase; MXenes; Photothermal conversion performance; Density functional theory; Exfoliation behavior; Photothermal conversion performance; MAX phase; MXenes
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.144921

The exfoliation behavior and superior photothermal conversion performance of six different MXenes have systematically revealed by combining experimental and theoretical studies, which will shed lights onto the effective design of diverse MXene materials and promote their applications from wearable devices, biomedical technology to solar water desalination.
[Display omitted]
•The different mono-M and double-M MXenes have been successfully synthesized.•The exfoliation behavior of MAX phases have been understood by theoretical study.•All the MXenes display fast-response and superior photothermal conversion ability.•The V2CTx MXene exhibits best saturation temperature, which outperforms Ti3C2Tx.•The results promote the rapid development of MXenes in photothermal applications.
Two dimensional transition metal carbides (MXenes) have attracted significant interest due to their unique layer structure, chemical diversity and superior physiochemical performances. However, most studies have focused on Ti3C2Tx, and the synthesis process and photothermal conversion capability of other MXenes remain unclear. In this work, we have systematically investigated the exfoliation behavior of six different MXenes, including mono-transition-metal (Ti3C2Tx, V2CTx, and Nb2CTx) and double-transition-metal (TiVCTx, TiNbCTx, and NbVCTx) MXenes derived from MAX phases, integrated with their photothermal conversion performance by combining experimental and theoretical studies. The phase, morphology, composition and surface groups of the different MXenes have been analyzed using XRD, SEM, XPS, and HRTEM techniques. Our results indicate a systematic variation in etching difficulty from difficult to easy, as Nb2AlC > NbVAlC > V2AlC > TiNbAlC > TiVAlC > Ti3AlC2, which correlates with the chemical composition and etching duration. Furthermore, the exfoliation factor m from density functional theory calculations reveals that the bond energies of M−A bonds are much weaker than M−X bonds in MAX phases, which agrees well with the experimental results. Interestingly that, all the obtained MXenes exhibit remarkable photothermal conversion performance with fast response, where the MXenes beyond Ti3C2Tx, such as V2CTx, NbVCTx, Nb2CTx, TiVCTx, and TiNbCTx, display higher saturation temperature of 95, 88, 81, 78, and 71 °C, respectively, than that of Ti3C2Tx (65 °C). These findings could potentially facilitate the efficient design and development of diverse MXene materials with outstanding photothermal conversion performance for applications in wearable devices, biomedical technology and solar water desalination.