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Ti2C is trigonal omega-like structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three Ti2C sheets oriented in the (0, 0, 1) direction. Ti2+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Ti–C bond lengths are 2.12 Å. C4- is bonded to six equivalent Ti2+ atoms to form edge-sharing CTi6 octahedra.
Ti2C is trigonal omega-like structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ti2+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Ti–C bond lengths are 2.11 Å. C4- is bonded to six equivalent Ti2+ atoms to form edge-sharing CTi6 octahedra.
Ti4C3(Ti2C)2 is trigonal omega-like structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of six Ti2C sheets oriented in the (0, 0, 1) direction and three Ti4C3 sheets oriented in the (0, 0, 1) direction. In each Ti2C sheet, there are two inequivalent Ti+2.50+ sites. In the first Ti+2.50+ site, Ti+2.50+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Ti–C bond lengths are 2.12 Å. In the second Ti+2.50+ site, Ti+2.50+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Ti–C bond lengths are 2.12 Å. C4- is bonded to six Ti+2.50+ atoms to form edge-sharing CTi6 octahedra. In each Ti4C3 sheet, there are two inequivalent Ti+2.50+ sites. In the first Ti+2.50+ site, Ti+2.50+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing TiC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.15 Å) and three longer (2.23 Å) Ti–C bond lengths. In the second Ti+2.50+ site, Ti+2.50+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Ti–C bond lengths are 2.07 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six Ti+2.50+ atoms to form a mixture of edge and corner-sharing CTi6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the second C4- site, C4- is bonded to six equivalent Ti+2.50+ atoms to form a mixture of edge and corner-sharing CTi6 octahedra. The corner-sharing octahedral tilt angles are 3°.
Much of the water desalination strategies has focused on designing pores and membranes that transport water and reject ions and other molecules at a high rate. In this paper, we discuss an approach where protons (H+) and hydroxide (OH−) ions are transported via different mechanisms through a porous membrane, and subsequently, once they have been transported through the membrane, they recombine to generate water. 2D materials such as graphene and MoS2 have generated significant interest for applications such as desalination. Here, we explore the applicability of one such 2D material—a cubic Ti2C MXene membrane—in desalination by creating a OH− ion selective pore, which significantly suppresses protons but allows OH− ions and water to go through. The catalytic properties of MXenes enable the dissociation of water on the surface, and the dissociated protons translocate through the membrane via quantum-dominated phenomena such as hopping from interstitial-to-interstitial. OH− ions translocate through a positively charged pore and recombine with protons on the other side of the membrane to form water. Our results indicate that water molecules generated via quantum processes can significantly enhance the overall transport of water across the membrane.