Highly efficient rectangular column-structured TiO2 photocatalysts have been developed by loading various metal nanoparticles on TiO2, such as copper (Cu/TiO2) or platinum (Pt/TiO2) by a photodeposition method. It was observed that with a Cu-loaded Cu/TiO2 photocatalyst, there was less decrease in the photocatalytic activity due to the poisoning of the photo-formed inorganics than with unloaded TiO2 catalysts.