Theoretical design of Sc2CF2/Ti2CO2 heterostructure as a promising direct Z-scheme photocatalyst towards efficient water splitting

Abstract

Van der Waals (vdW) heterostructure catalysts with the direct Z-scheme charge transfer path are highly expected for photocatalytic water splitting to address the energy crisis. In this work, the novel Sc2CF2/Ti2CO2 heterostructure has been developed and its photocatalytic utility was evaluated based on the first-principles method. Results indicate the heterostructure is an indirect semiconductor with improved carrier mobilities and absorption. The transfer of photogenerated carriers in this heterostructure follows the Z-scheme path, and the band edge positions confirm its suitability for water splitting. More importantly, the change in Gibbs free energy indicates that solar energy can drive water splitting in Sc2CF2/Ti2CO2 heterostructure with an attractive solar-to-hydrogen efficiency of 41.7%. Besides, biaxial tensile strain can turn Sc2CF2/Ti2CO2 heterostructure into a direct semiconductor, while its photocatalytic performance can be improved. In brief, all findings prove the potential of Sc2CF2/Ti2CO2 heterostructure as a promising direct Z-scheme photocatalyst for efficient water splitting.