MXenes are a fast-emerging class of two-dimensional (2D) nanomaterials of transition metal carbides in a graphene-like structure with applications in the fields of biomedicine, environmental science, and energy storage. MXenes are typically derived from the MAX phase, Mn+1AXn, where M is an early transition metal, A is an element such as Al, Si, or Ga, and X can be either C or N. The A-layer atoms can be etched out in an acidic aqueous environment such as HF. leaving behind layers of Mn+1Xn.  This removal process dictates the surface terminations of the resulting MXene. The surface termination of the structure plays a significant role in the stability and reactivity of the overall system. Our work investigates how solution conditions such as pH can affect the favorability of likely terminations with the use of a DFT and thermodynamics methodology. We have predicted the pH dependence for the -O, -OH, and -F terminations on the Ti3C2 surface, as it is the most well studied of these species to date. We now are investigating the effects of substituting different transition metals into the lattice structure on surface formation.  As the Ti3C2 structure has two transition metal layers on which the surface terminations form, we predict that substituting these Ti for metals such as Nb and Mo will have greater effect than doping the inner layer. This work helps to predict surface terminations for a range of compositions and environments, helping to understand and design MXene functionality.

DFT plus thermodynamics investigation of transition metal(Mo/Nb) doping Ti3C2T2 (T = O, OH, F) MXene at varying pH

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.