Electronic properties,quantum capacitance and photocatalyst for water splitting of Sc2CO2 MXene under uniaxial strain

MXenes have wide applications because of the structural flexibility and compositional diversity. Quantum capacitance, electronic and photocatalytic properties of Sc₂CO₂ monolayer under uniaxial strains are investigated by first-principles calculation. Sc₂CO₂ monolayer can withstand stress up to 13.96 N/M and about 14% tensile uniaxial strain limit. Sc₂CO₂ undergoes a transition from semiconductor to metal at ?15% uniaxial strain. Sc₂CO₂ under uniaxial strains are only used for the water reduction at pH = 0. Sc₂CO₂ under uniaxial strains of ?10%, ?7%, ?3%, 0%, and 4% within the appropriate pH scope are potential photocatalysts for water redox reaction. Sc₂CO₂ with ?15% uniaxial strain is promising anode material, and Sc₂CO₂ with tensile uniaxial strain is more potential cathode material. Wide voltage improves the top quantum capacitance at negative bias under uniaxial strain and keeps the type of electrode materials. Quantum capacitance of Sc₂C with mixed termination (Sc₂CO_0.59F_1.19(OH)_0.22) under uniaxial strain is explored. The introduction of uniaxial strain and mixed termination has little effect on the electrode type of Sc₂CO₂ MXene.