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 O 2 -bridged dimer complex on the surface resembling hemocyanin in the biosystems (Cu(acac) 2 / ms -BiVO 4 ). Visible-light irradiation of Cu(acac) 2 / ms -BiVO 4 in ethanol aqueous solution gives rise to a two-electron oxygen reduction reaction, whereas unmodified ms -BiVO 4 is entirely inactive. The replacement of Cu(acac) 2 by bis(hexafluoroacetylacetonato)Cu(II) drastically enhances the photocatalytic activity to yield H 2 O 2 with an external quantum yield of 0.47% at λ ex = 470 nm. Electrochemical measurements show high selectivity (∼100%) for the two-electron reduction of O 2 . The compatibility of the high photocatalytic activity and selectivity can stem from the charge separation enhancement via the interfacial electron transfer from ms -BiVO 4 to the surface complex and its O 2 -enriching effect near the ms -BiVO 4 surface and excellent electrocatalysis for two-electron ORR.