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.