CONSIDERATION OF REACTOR DESIGN FOR SOLAR HYDROGEN-PRODUCTION FROM HYDROGEN-SULFIDE USING SEMICONDUCTOR PARTICULATES

A series of experiments was performed to guide development of reactor configurations for photochemical hydrogen production from H2S based on semiconductor particulates. Platinized cadmium sulfide was utilized as the photocatalytic material. Powder suspensions, colloids, sedimentary dispersions and immobilized particle beds were studied. Colloidal systems had the greatest activity on a per gram basis, due to their increased surface area. Sedimentary systems gave an optimized activity at a loading of about 1 mg cm(-2), but uniform distribution of particulates was difficult to achieve and maintain. Immobilized particle systems perform at only 25-50 % the activity of free particle systems, but are advantageous in terms of ease of product separation. Issues of reaction kinetics, alkaline scrubber efficiency, ease of sulfur recovery and market economics combine to discourage addition of the sulfite ion as a carrier for the photoproduced sulfur.