The system with a nitride semiconductor and a metalcatalyst generates mainly formic acid from CO2 and water with light at a world's top efficiency of 0.2%.
The CO2 reduction takes place on a metalcatalyst at the opposite side of nitride semiconductor photo-electrode.(See Fig. 1) The metalcatalyst plays an important role in selecting and accelerating the reaction.
Platinum: As a primarily industrial metal, platinum plays the role of catalyst in the processing of petroleum and chemicals such as nitric acid, fertilizers and synthetic fibers.