Cu-doped ZnS hollow particle with high activity for hydrogen generation from alkaline sulfide solution under visible light

Visible light sensitive and highly active Cu-doped ZnS hollow photocatalyst particles "Cu-ZnS-shell" were successfully developed. These particles could generate H₂ through photocatalytic decomposition of HS ^- ion in Na₂S solution. The photoactivity under xenon lamp irradiation was 6 and 130 times higher than that of copper-free "ZnS-shell" and coprecipitated ZnS particles, respectively. "Cu-ZnS-shell" particles were prepared by doping the "ZnS-shell" particles synthesized using zinc oxide as precursor with Cu, utilizing the difference in ionization tendency between zinc and copper. Though the photoactivity of "ZnS-shell" was higher than that of coprecipitated ZnS, their photoactivity under visible light conditions was low. However, the "Cu-ZnS-shell" was active to light of wavelengths higher than 440 nm and is preferred over CdS, which requires an expensive support metal catalyst such as platinum to decompose HS^- ion.