Visible-Light-Driven Hydrogen Peroxide Synthesis by a Hybrid Photocatalyst Consisting of Bismuth Vanadate and Bis(hexafluoroacetylacetonato)copper(II) Complex

The adsorption of bis(acetylacetonato)Cu(II) on monoclinic scheelite bismuth vanadate forms an O₂-bridged dimer complex on the surface resembling hemocyanin in the biosystems (Cu(acac)₂/ms-BiVO₄). Visible-light irradiation of Cu(acac)₂/ms-BiVO₄ in ethanol aqueous solution gives rise to a two-electron oxygen reduction reaction, whereas unmodified ms-BiVO₄ is entirely inactive. The replacement of Cu(acac)₂ by bis(hexafluoroacetylacetonato)Cu(II) drastically enhances the photocatalytic activity to yield H₂O₂ with an external quantum yield of 0.47% at λₑₓ = 470 nm. Electrochemical measurements show high selectivity (∼100%) for the two-electron reduction of O₂. The compatibility of the high photocatalytic activity and selectivity can stem from the charge separation enhancement via the interfacial electron transfer from ms-BiVO₄ to the surface complex and its O₂-enriching effect near the ms-BiVO₄ surface and excellent electrocatalysis for two-electron ORR.