Does Cuprous Oxide Photosplit Water?

A thin film of copper(I) oxide (thickness ∼9 Å), grown on a Cu(111) crystal, was used as a model photocatalyst for decomposition of D 2 O using ultraviolet light ( h ν = 1.55−6.21 eV). No evidence for water photosplitting was observed. The experimental uncertainties establish an upper limit of 2 × 10 -21 cm 2 for the cross section of the photoprocess sought. The pure Cu 2 O film was grown by bombardment with O 2 + ions (1.5 kV) at a sample temperature of 605 K and was characterized by Auger electron spectroscopy.