Synthesis and Surface Chemistry of 2D TiVC Solid-Solution MXenes

Abstract

MXenes are emerging two-dimensional (2D) materials for energy-storage applications and supercapacitors. Their surface chemistry, which determines critical properties, varies due to different synthesis conditions. In this work, we synthesized TiVC solid-solution MXenes by two different synthesis methods and investigated their surface functional groups. We performed etching of the TiVAlC MAX phase using two different solutions, a highly concentrated HF (50 wt % ≈ 29 M) and a mixture of LiF and HCl (1.9 M LiF/12 M HCl). Large-scale delamination of TiVCT x to produce single-flake suspension was achieved by further intercalation of the resultant MXene from LiF/HCl with tetrabutylammonium hydroxide (TBAOH). X-ray diffraction indicates a large interlayer spacing of 2.18 nm for TiVCT x MXene flakes. To investigate the structural stability and adsorption energy of different functional groups on TiVC MXenes, density functional theory (DFT) calculations were performed and supported with X-ray photoelectron spectroscopy (XPS) measurements. A higher concentration of O and a lower concentration of −F were achieved on the TiVC synthesized by LiF/HCl, both of which provide a more favorable surface chemistry for energy-storage applications. Our results provide the first systematic study on the effect of synthesis conditions on the surface chemistry of solid-solution TiVC MXenes.

Ti3C2TX MXene for Sensing Applications: Recent Progress, Design Principles, and Future Perspectives

“…In 2013, MXene nanosheets were exfoliated into single layer by inserting large organic molecules into the interlayers of the accordion-like structure followed by mechanical vibration or ultrasonication. , The commonly used intercalants include tetrabutylammonium hydroxide (TBAOH), dimethyl sulfoxide, hydrazine, urea, and NH 4 + . ,− For example, Chia and co-workers used TBAOH as the intercalant to exfoliate Ti 3 C 2 T X MXene from the products obtained via HF etching (Figure a) . As shown in Figure b, MAX powder with micron-sized flakes was expanded after the removal of Al, and the obtained Ti 3 C 2 -HF was delaminated into single-/fewer-layer MXenes by weakening the interlayer interaction using TBAOH.…”

Rational Design of Two-Dimensional Transition Metal Carbide/Nitride (MXene) Hybrids and Nanocomposites for Catalytic Energy Storage and Conversion

“…For instance, the Ti surface of Ti 3 C 2 T x implies that only Ti-based secondary materials can be grown through this conversion route. In this regard, we anticipate that disordered solid solution MXenes such as (Ti,V) 2 CT x and (Mo,V) 4 C 3 T x , denoted by the chemical formula (M′ , M″) n +1 X n T x , will be interesting for growth of secondary materials through this surface conversion route, since they possess two different TMs at the surface in a random distribution …”

Progress and Perspective: MXene and MXene‐Based Nanomaterials for High‐Performance Energy Storage Devices

“…[ 32–34 ] Moreover, to date, a series of multiple‐M solid‐solution MXene have been investigated, consisting of (M′,M″) 2 XT x (Ti 2‐ y Nb y CT x , Ti 2‐ y V y CT x , and V 2‐ y Nb y CT x ) (Figure 1b), [ 35 ] (M′,M″) 3 X 2 T x (Ti 1.5 V 1.5 C 2 T x , (V 0.5 ,Cr 0.5 ) 3 C 2 T x ), and (M′,M″) 4 X 3 T x ((Mo,V) 4 C 3 T x , Nb 3.2 Zr 0.8 C 3 T x , and Nb 3.2 Ti 0.8 C 3 T x ) compositions framing continuous solid solutions on M‐site. [ 36–41 ] Generally, the M–X bond provides metallic, ionic, and covalent characters, exhibiting higher binding energy than the M–A bond. Hence, the M–A bond in MAX can be more easily broken than M–X bond.…”