Biaxial strain tunable electronic properties, photocatalytic properties and quantum capacitance of Sc2CO2 MXenes

Abstract

First-principles calculation was adopted to study quantum capacitance, electronic and photocatalytic properties of Sc2CO2 monolayer under biaxial strain. Our study shows that Sc2CO2 can bear the maximum stress of 14.895 N/M. Sc2CO2 with −10% strain undergoes the semiconductor-metal transition due to the blue shift of C-p, Sc-d, and O-p orbitals. The analysis of photocatalytic properties indicates that monolayer Sc2CO2 under the biaxial strain from −6% to 2% can produce spontaneous water splitting reaction in appropriate pH range. The influence of biaxial strain on electrode type is also investigated in aqueous and ionic/organic systems. The results indicate that biaxial strain has little impact on electrode type of materials except −10% strain. Sc2CO2 with −10% strain is suitable for anode material, while Sc2CO2 under other strains is potential cathode material. The introduction of mixed termination has little influence on the electrode type of Sc2CO0·42F1·19(OH)0.4 under strains. The wide potential has little influence on electrode type of Sc2C with pure –O and mixed termination.