Background
In this paper, the application of two-dimensional Ti3C2 MXENE as a catalyst for photocatalytic hydrogen production was studied. MXenes are a class of transition metal carbides and nitrides, which have special properties to enhance photocatalytic reactions. In this study, the performance of Ti3C2 MXENE as a cocatalyst for photocatalytic systems was studied, aiming to improve charge separation, inhibit recombination, and promote efficient hydrogen evolution in water irradiated with light. The synthesis method, catalyst loading strategy and overall photocatalytic mechanism of Ti3C2 MXENE were studied, revealing the potential of Ti3C2 MXENE as a promising sustainable hydrogen production material. In the context of significant progress in 2D MXENES, various reviews describe different synthesis methods of MXenes and their applications. Compared to other MXenes, the TI3C2 MXENE offers several advantages and benefits that contribute to its uniqueness and applicability in various fields. Its excellent electrical conductivity, surface functional groups, hydrophilicity, tunable band gap, stability, active site, compatibility, catalytic diversity, ease of synthesis, and established research base make it the Mxene of choice for advancing various photocatalytic processes and other sustainable technologies. Compared to other members of the MXENE family, Ti-MXENE stands out as a research-prominence MXENE. Almost 70% of MXENES-related studies were Ti3C2 MXenes, and the remaining 30% consisted of MO, NB, V, CR, W, ZR, HF, TA, SC, and MXENES-based. From the theoretical and experimental results, Ti3C2 has better electrical conductivity than other MXenes. At the same time, it is pointed out that Ti3C2 MXENE has high stability compared with other MXENEs. Due to the properties of Mxenes and the availability of a large number of active sites, it is promising to be used as a photocatalyst. However, since MXEnees are not semiconductors, they cannot be used directly as photocatalysts. Therefore, MXENES composites with different compositions can be effectively applied in different fields. In this paper, we discuss the use of MXENES as a catalyst for photocatalytic hydrogen evolution (HERS), various synthesis methods of MXENES-derived photocatalysts, the challenges of this system, and the future prospects of this field.
Full text guide
Figure 1Representation of the individual steps in an overall water splitting reaction using a photocatalyst in the presence of light.
Figure 2The structure of M2X, M3X2 and M4X3 and their different compositions.
Figure 3(a) Articles published annually in 2D MXenes (data from Scopus-indexed journals). (b) General preparation method of MXENE.
Figure 4Synthesis of MXENE from the MAX phase by HF acid etching.
Figure 5Modified etching method for MXENE synthesis.
Figure 6Non-fluorinated etching method for the synthesis of MXENE.
Figure 7Hydrothermal preparation of MXENE.
Figure 8MXene was synthesized using LIF HCL etching technology.
Figure 9The process of etching Ti3Alc2 to produce Ti3C2.
Figure 10(A) Image of an MXENE sheet of Ti3C with surface functional groups. (b) Slow oxidation of surface functional groups and Ti3C2TX.
Figure 11(A) Photocatalytic HER mechanism using CDS Ti3C2 catalyst. (b) Use CD05zn0.HER rate of 5S Ti3C2 composites in seawater and pure water.
Figure 12(a) photocatalytic HER activity and (b) HER rate on different Ti3C2 TiO2 Cuins2. (c) Photocatalytic H2 production and (d) photocatalytic H2 production rates using different catalysts in acetone aqueous solution using Ti3C2 TiO2 1 T-MOS2 composites over 8 hours.
Figure 13(A) HER mechanism using MOS2 TiO2 Ti3C2. (B) HER mechanism using Ti3C2 ZnIn2S4 TiO2 in sunlight.
Figure 14(A) Photocatalytic H2 production activity of Ti3C2 PT G-C3N4 and (B) ZNS-CDS samples.
Figure 15Illustration of the preparation of Cuy tio2@ti3c2tx composites.
Figure 16(a) Application of the three-way photocatalyst Cuy tio2@ti3c2tx in H2 production and (b) Reusability of the catalyst for water cracking reactions.
Figure 17Illustration of photocatalytic H2 production using G-C3N4 Ti3C2 composites.
Figure 18(a,b) Schematic diagram of the photocatalytic hydrogen evolution mechanism of ti3c2@tio2@mos2 composites.
Figure 19Schematic diagram of the mechanism of MXENE as a photocatalyst.
Figure 20Behavior of 2D MXENE as a functional group provider, substrate, photocatalytic electron acceptor, and cocatalyst.
Figure 21(A) A rational mechanism for photocatalytic HER using 0D TiO2 Ti3C2. (b) Photocatalytic hydrogen production mechanism using 1D TiO2 Ti3C2.
Figure 22Photocatalytic hydrogen production mechanism using 2D 2D-Ti3C2 G-C3N4.
Summary
MXEnes has aroused the curiosity of researchers due to its surface morphology and electronic properties. Previous studies have shown that the MXENE material is in the early stages of development and requires further research. In addition, the two-dimensional Ti3C2 MXENE materials and their composites, various synthesis strategies, and the applications of these MXene materials are introduced. One of the most important applications of MXENE photocatalytic HER is also discussed. In order to exhibit optimal catalytic activity, oxygen terminates on the MXENE surface. In addition, the photocatalytic performance was improved by introducing photoactive materials such as TiO2, ZNO, and MOS2. The presence of MXENES in the composites improves light absorption, enhances charge separation, and increases the number of active sites. While these materials have many advantages, certain disadvantages limit their practicality. The main obstacle is that they are prepared from the corresponding max phase stage, which is difficult to maintain stability after peeling. Researchers are looking for new stripping methods to synthesize mxenes, which are promising. In addition to the traditional AL Max stage, it is necessary to explore more new members of the MAX family.
In summary, MXENES offers a variety of opportunities for photocatalysis. Combined with the application of photocatalytic HER, the electronic properties and surface functional groups of MXenes are discussed. This article provides a comprehensive introduction to MXEnes and its properties in photocatalytic HER. In addition to photocatalytic her, MXEnes is also promising in many other applications such as solar conversion, batteries, and supercapacitors. In the future, MXENES and its applications in the fields of photocatalysis, energy and environment have broad prospects.