First-principle study of electronic, optical, quantum capacitance, carrier mobility and photocatalytic properties of Zr2CO2 MXene under uniaxial strain

Abstract

The electronic and optical properties, quantum capacitance and photocatalytic performance of Zr2CO2 under uniaxial strain are investigated by density functional theory (DFT). The carrier mobility of Zr2CO2 MXene is also explored. Zr2CO2 can withstand the maximum stress of 9.3 N/M and its tensile limit is 18 % strain. All systems have the character of indirect semiconductor and are mechanically stable within elastic limit. The compressive strain significantly increases the hole mobility in x-direction. Electrons in y-direction have higher mobility in free and tensile strain. Tensile strain generally enhances the performance of Zr2CO2 as cathode material, while compressive strain makes the system transfer from cathode to anode material. Zr2CO2 with larger strain than 7 % has excellent CO2 photocatalysis, CO2 is reduced to CH4, CH3OH, HCHO, CO and HCOOH at pH = 0. Zr2CO2 with strain from −7 to 11 % can reduce N2 to NH3. Work function and photocatalytic properties at pH = 7 are also explored.