Cadmium Sulfide - Reactions

Reactions

Cadmium sulfide is soluble in (actually degraded by) acids, and this conversion has been investigated as a method of extracting the pigment from waste polymers e.g. HDPE pipes:

CdS + 2 HCl → CdCl2 + H2S

When sulfide solutions containing dispersed CdS particles are irradiated with light hydrogen gas is generated:

H2S → H2 + S ΔHf = +9.4 kcal/mol

The proposed mechanism involves the electron/hole pairs created when incident light is absorbed by the cadmium sulfide followed by these reacting with water and sulfide:

Production of an electron hole pair
CdS + → e− + hole+
Reaction of electron
2e− + 2H2O → H2 + 2OH−
Reaction of hole
2hole+ + S2− → S

Read more about this topic:  Cadmium Sulfide

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