Hydrogen Peroxide Production by Inorganic Photocatalysts Consisting of Gold Nanoparticle and Metal Oxide toward Oxygen Cycle Chemistry

Hydrogen peroxide (H2O2) is not only a versatile clean and strong oxidant but also a promising fuel for fuel cells. This Feature Article has shown that gold nanoparticle (NP)-loaded metal oxides (Au/MOs) can be promising photocatalysts for H2O2 production via two electron-oxygen reduction reaction (2e-- ORR). The fundamental parts deal with the general requirements for the H2O2 synthesis, electrocatalytic activity of Au NPs for 2e-- ORR, Fermi level control of the Au NP of Au/MOs in the dark and under light irradiation, and the factors for governing the catalytic activity for H2O2 production. Subsequently, an artificial photosynthesis of H2O2 from water and O2 under visible light irradiation at ambient temperature and pressure is described. Finally, the conclusions are summarized with a direction of the future research on the hot topics.