Highly value-added utilization of H₂S in Na₂SO₃ solution over Ca-CdS nanocrystal photocatalysts

Alkaline-earth metal Ca²⁺ modified CdS nanocrystals have been designed for the first time for highly efficient H₂ evolution from hydrogen sulfide (H₂S) with Na₂SO₃ as a favourable reaction medium. The advantage of Na₂SO₃ was revealed by an electrochemical test, and the conversion of Na₂SO₃ during the reaction was carefully studied. Particularly, most of Na₂SO₃ was converted into Na₂S₂O₃. Highly value-added utilization of waste H₂S is therefore achieved via photocatalysis.