Au/Cu2O Schottky contact heterostructures with enhanced photocatalytic activity in dye decomposition and photoelectrochemical water splitting under visible light irradiation

• Au/Cu2O heterostructures were realized by a facile chemical strategy.
• Photocatalytic activity of Au/Cu2O was studied in MO degradation and water splitting.
• Photocatalytic activity of heterostructures is remarkably enhanced.
• Photocatalytic mechanism on Au/Cu2O under visible light irradiation was proposed.
• The Schottky junction retards the recombination of photo-induced charges.

In this work noble metal Au nanoparticles have been successfully deposited on the surface of Cu2O microcubes to construct close Au/Cu2O Schottky contact heterostructures, in which both an inner electronic field from Au to Cu2O and a Schottky barrier are established at the interface of Au and Cu2O due to the Schottky junction. Benefiting from this unique structure with synergistic effect of inner electronic field and Schokkty barrier, the as-fabricated Au/Cu2O Schottky contact heterostructures exhibit enhanced photocatalytic activity to pure Cu2O microcubes in dye decomposition and water splitting under visible light illumination. The photodegradation rate of the as-constructed Au/Cu2O Schottky contact heterostructures for methyl orange (MO) is 1.2 times higher than that of pure Cu2O microcubes under visible light irradiation for 90 min. The photocurrent density of the as-prepared Au/Cu2O heterostructures electrode reaches up to 30 μA cm−2, which is 3 times higher than that (10 μA cm−2) of pure Cu2O microcube electrode at 1.23 V vs RHE. The enhanced photocatalytic activity of the as-constructed Au/Cu2O Schottky contact heterostructures is attributed to the synergistic effect of inner electronic field and Schokkty barrier. The transfer process of the photoexcited electrons and holes, and the enhancement mechanism of photocatalytic performance of the as-fabricated Au/Cu2O heterostructures are discussed in detail. This study opens up new opportunities in designing photoactive materials with highly enhanced performance for solar energy conversion.