Tunable photocatalytic water splitting and solar-to-hydrogen efficiency in β-PdSe2 monolayer†
Direct production of hydrogen from photocatalytic water splitting is a potential solution to overcome global energy crisis. Herein, based on first-principles calculations, we demonstrate that the two-dimensional β-PdSe2 monolayer is a promising candidate for efficient photocatalytic water splitting in acidic and alkaline media as well as neutral medium with highly efficient solar-to-hydrogen efficiency. β-PdSe2 monolayer shows low cleavage energy which endorses the possibility of its mechanical exfoliation from layered bulk β-PdSe2. Remarkably, β-PdSe2 monolayer is semiconducting with indirect band gap of 1.96 eV with perfect engulfing the redox potential of water in a wide range of pH of medium. β-PdSe2 monolayer exhibits good light harvesting ability and adequate driving forces for water redox reaction in wide range of pH (0 to 12). Comprehensive investigation of pH dependent water splitting indicates that the β-PdSe2 monolayer is a better candidate for efficient water splitting in alkaline media rather than acidic or neutral medium. In addition, high solar-to-hydrogen efficiency as high as ∼17% is obtained that shows β-PdSe2 monolayer a promising candidate for overall photocatalytic water-splitting.