Computational Investigation on Cr-Doped Sc₂CO₂ MXene under Strain for Electronic Properties, Quantum Capacitance, and Photocatalytic Activity

Sc₂CO₂ MXene has potential applications in energy storage and optoelectronics due to its superior structure and excellent properties. The electronic properties, quantum capacitance, and photocatalytic activity of Cr-doped Sc₂CO₂ under strain are studied by the density functional theory. Cr doping makes the system produce magnetism. The spin-down states of Sc₂CO₂-Cr under strain are direct semiconductors, while their spin-up states are indirect semiconductors. Sc₂CO₂-Cr under +5, -5, -3, and -2% strains in an aqueous system are suitable for cathode material. A large voltage drastically modulates the type of electrode materials. Sc₂CO₂-Cr under strains from 0 to +2% can perform the oxygen evolution reaction at an alkaline environment, while the Sc₂CO₂-Cr system under strain is a good for CO₂ photocatalysis at pH 0 and 7.