Layered SnSe_xS_2−x alloys with fully chemical compositions and band gaps for photoelectrochemical water oxidation

The water oxidation reaction plays a vital role in photoelectrochemical (PEC) water splitting, especially in a water-neutral electrolyte. In this work, photoanode SnSe_xS_2−x alloys with fully tunable chemical compositions were synthesized by chemical vapor deposition (CVD). The modulated band gap values were also realized from 2.24 to 1.37 eV, and the corresponding optical properties were further modified in the SnSe_xS_2−x alloys. Compared with pure SnS₂ and SnSe₂, especially in a 0.5 M Na₂SO₄ electrolyte without a sacrificial agent, the PEC performance of SnSe_xS_2−x alloys can be obviously improved by increasing the photocurrents, which contributes to the excellent photoelectrical catalytic activity of SnSe_xS_2−x alloys. This work provides the way to prepare environmentally friendly chalcogenide alloys for promising applications in optical and PEC water splitting. (paper)