Photocatalytic Hydrogen Production with Cds and Cds/znS Modified by Different Electron Hole Transfer Additives Using Visible Light

Photocatalytic production of hydrogen using CdS suspensions in aqueous solution containing Na₂S-Na₂SO₃ has been studied. CdS prepared from different salts of Cd(II) and Na₂S or H₂S shows different photocatalytic activity towards generation of hydrogen. Use of excess of Cd²⁺ or S^2- in the preparation of CdS affects its photocatlytic activity. Pt, Pd, Ag₂S or RuO₂ have been added to CdS in different proportions. In each case, a maximum hydrogen production is observed at a definite composition. In case of CdS/ZnS mixture, the intimate contact of Pt with CdS is absolutely necessaly in exerting the role of Pt for enhancing the hydrogen evolution by the ternary semiconductor system. Attempt has been made to correlate the photocatalytic activity order of the semiconductors to their luminescence property.