The preparation route and final form of V-MXenes override the effect of the O/F ratio on their magnetic properties

This work was supported by OP VVV “Excellent Research Teams” project no. CZ.02.1.01/0.0/0.0/15_003/0000417 – CUCAM. P. E. would like to also acknowledge the Czech Science Foundation for the ExPro project (19-27551X). Computational resources and low-temperature infrastructure were supplied by the projects “e-Infrastruktura CZ” (e-INFRA CZ LM2018140) and MGML (LM2023065) supported by the Ministry of Education, Youth and Sports of the Czech Republic.Transition metal carbides and nitrides (MXenes) show a high potential for electrochemical energy storage in batteries and supercapacitors and for electrocatalysis. Their excellent electronic and magnetic characteristics have been highlighted in several theoretical studies. However, experimental research on MXenes is yet to confirm their predicted properties as candidates for controllable magnetic 2D materials. Here, we report our theoretical and experimental study of V2CTx MXenes (T = O, OH, F), providing key insights into their magnetism. Based on our density functional theory (DFT) analysis, we predicted ferromagnetic (FM) and antiferromagnetic (AFM) states of V2CTx, which are determined by the O/F ratio of surface functional groups. Accordingly, we prepared V2CTx MXenes in the form of multilayered powders and thin films with different O/F ratios. No experimental evidence of FM or AFM properties was found in any material. Nevertheless, powders and films with almost identical chemical compositions (in terms of O/F ratio) displayed different magnetic properties, whereas films with disparate chemical compositions revealed a similar magnetic character. Therefore, the preparation route and form of the final V2CTx material override the effect of the O/F ratio, which is often overestimated in theoretical studies. Moreover, these findings underscore the importance of preparing MXene materials to experimentally confirm their theoretically predicted properties.Peer reviewe

Genres nouveaux et peu connus de coraux Scléractiniaires des calcaires de Štramberk (Jurassique supérieur de République tchèque)

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Introduction to 3D Planning in Orthognatic Surgery. 3D Simulation of Orthognatic Surgery Using Dolphin Imaging 3D® Software

AIM: Recently there has been a great progress in three-dimensional (3D) technologies in field of medicine. Dentistry and maxillofacial surgery haven't been exceptions. Methods such as model surgery or cephalometric methods of prediction (2D prediction) including video imaging are considered as "gold standards" in orthognathic surgery. However, these techniques, despite being routine part of the diagnosis and treatment planning process, have their limitations. 3D environment adds the third dimension to planning, which moves planning closer to reality and gives us more information for diagnosing a wider range of dentofacial anomalies. Furthermore, 3D planning increases accuracy of overall orthognatic planning by using modern 3D imaging methods, such as Cone Beam CT, stereophotogrammetry or digital models of dental arches. By merging these 3D images is created virtual model of patient head, described by some authors as triad. It depicts facial skeleton (Cone Beam CT), facial soft tissues (stereophotogrammetry scan) and dental arches (digital models) in the most suitable way. The next step is to perform 3D simulation on this virtual model by using a planning software, e.g. Dolphin imaging 3D®. The aim of this article is to present relatively new method of orthognatic surgery planning and brings some information about 3D imaging technologies, which are essential as part of that process. Simultaneously fundamental steps (procedures) in orthognatic surgery 3D simulation using program Dolphin Imaging 3D® process are described

The preparation route and final form of V-MXenes override the effect of the O/F ratio on their magnetic properties

Transition metal carbides and nitrides (MXenes) show a high potential for electrochemical energy storage in batteries and supercapacitors and for electrocatalysis. Their excellent electronic and magnetic characteristics have been highlighted in several theoretical studies. However, experimental research on MXenes is yet to confirm their predicted properties as candidates for controllable magnetic 2D materials. Here, we report our theoretical and experimental study of V2CTx MXenes (T = O, OH, F), providing key insights into their magnetism. Based on our density functional theory (DFT) analysis, we predicted ferromagnetic (FM) and antiferromagnetic (AFM) states of V2CTx, which are determined by the O/F ratio of surface functional groups. Accordingly, we prepared V2CTx MXenes in the form of multilayered powders and thin films with different O/F ratios. No experimental evidence of FM or AFM properties was found in any material. Nevertheless, powders and films with almost identical chemical compositions (in terms of O/F ratio) displayed different magnetic properties, whereas films with disparate chemical compositions revealed a similar magnetic character. Therefore, the preparation route and form of the final V2CTx material override the effect of the O/F ratio, which is often overestimated in theoretical studies. Moreover, these findings underscore the importance of preparing MXene materials to experimentally confirm their theoretically predicted properties