Electrochemical photocatalytic structure

An electrochemical photocatalytic structure for photosensitizing chemical reduction-oxidation reactions including:

• a substrate means for providing physical support for said structure;
• a film of catalyst material deposited on said substrate means;
• a porous layer of semiconductor powder adjacent said catalyst material, and adapted for photoactivity wherein said semiconductor powder layer has a porosity of about 50% to about 75% and has a grain size less than about 1 micrometer to 0.02 micrometer, at least some of said semiconductor powder grains are in contact with said film of catalyst material, and at least a portion of said film of catalyst material is uncovered by said semiconductor powder grains so as to be exposed for electrochemical reaction;
• and
• said semiconductor powder including spaced grains of semiconductor material to provide a pore volume so as to pass a chemical reactant which is subjected to a photochemical reduction-oxidation reaction when said structure is illuminated with light having a wavelength with an energy above the electron bandgap energy of said semiconductor material so that both electron and hole carriers are created in said layer of semiconductor powder.