Comparative study of functionalized MXenes Mn+1CnO2 (M = Ti, Zr and Hf, n = 1, 2 and 3): A proposal for renewable energy applications

Abstract

Using first-principles calculations, we studied the electronic, structural and thermoelectric properties of two-dimensional (2D) MXenes [Formula: see text] ([Formula: see text] = Ti, Zr and Hf, [Formula: see text], 2 and 3). The calculations are carried out within the generalized gradient approximation (GGA). We have calculated the Boltzmann transport equation for finding the thermoelectric properties such as power factor, Seebeck coefficient and electrical conductivity. For [Formula: see text], these materials behave as semiconductors having an indirect bandgap nature. In contrast, for [Formula: see text] these materials show metallic behavior. Out of these MXenes, we found that Ti2CO2 has a high Seebeck coefficient value, whereas the electrical conductivity of Ti4C3O2 is exceptionally high. While among all these compounds, Ti2CO2 and Hf4C3O2 have a high power factor in the 300–1200-K temperature range.