Halogenated Ti₃C₂ MXenes Prepared by Microwave Molten Salt for Hg⁰ Photo‐Oxidation

Abstract

Ti 3 C 2 MXenes with different halogen modifications are prepared rapidly and efficiently by microwave molten salt method, and the MXene surface functional group modification is successfully achieved to address the problems of low purity, complex functional groups, and uncontrollable energy band structure of MXenes obtained by traditional liquid phase etching. Among them, the modification of the iodine (I) functional group onto the surface of Ti 3 C 2 changes the energy band structure and band gap, resulting in easier photoexcitation and more photogenerated carriers. The increased Fermi energy is closer to the conduction band, the decreased surface work function weakens the electron confinement ability. The photogenerated carriers can migrate to the surface of the material more easily with extended lifetime, so the activity of the catalyst is improved. Further, for gaseous monomeric mercury (Hg 0 ) photo-oxidative removal, Ti 3 C 2 -I 2 exhibits 85.5% efficiency of Hg 0 photo-oxidative removal under visible light. Based on the experimental characterization and density functional theory calculations, a mechanism for the photooxidative removal of Hg° from Ti 3 C 2 -I 2 MXene is proposed, which provides a valuable strategy for studying Ti 3 C 2 MXenes in the field of photocatalysis.

Solvation structure design for stabilizing MXene in transition metal ion solutions

“…CoO/Ti 3 C 2 T x with a typical 2D structure embedded with smaller nanosheets is revealed by the TEM image (Figure 4G). The high‐resolution TEM image in Figure 4H exhibits the lattice distance of 0.48 and 0.27 nm, which match well with the (004) and (110) facet of Ti 3 C 2 T x 34,35 . The lattice distance of 0.22 nm corresponds well to the (200) facet of CoO.…”

“…The high-resolution TEM image in Figure 4H exhibits the lattice distance of 0.48 and 0.27 nm, which match well with the (004) and (110) facet of Ti 3 C 2 T x . 34,35 The lattice distance of 0.22 nm corresponds well to the (200) facet of CoO. Moreover, the energy dispersive X-ray spectra mappings of CoO/Ti 3 C 2 T x also confirmed the uniform distribution of CoO nanosheets on Ti 3 C 2 T x (Figure 4I).…”

A review on surface modulation of MXenes and the impact on their work functions and stability

“…Furthermore, this method will result in a decrease in the interlayer spacing of the generated MXenes. 53 As demonstrated in Fig. 5b, the XRD patterns clearly exhibited (002) and (004) peaks of Ti 3 C 2 , 55,56 and both peaks showed varying degrees of shift.…”

“…58 Nevertheless, in the fundamental principle of preparing MXenes from the MAX phase, it is necessary to use the etchant to etch the A atomic layer. As a consequence, some loss in 53 MXene performance appears to be an inherent outcome of the preparation process.…”

In situ construction of halogen MOF bifunctional catalysts for synergistic removal of NO and Hg0

“…Analyzing and clarifying the properties of active sites and the structure-performance relationship of halogen-modified Cu-Ce-BTC catalysts can offer valuable insights for the proficient construction of catalysts. 21 However, a comprehensive understanding of research in this area is still lacking, and there exists no consensus on how to precisely adjust the structure of Cu-Ce-BTC catalysts to achieve the requisite catalytic performance.…”