The paper highlights less-common properties of nanosized WO3 thin films which make it possible to achieve photolysis in CuCl films via the use of a CuCl-WO3 double-layer structure. The WO3 film provides first photoinduced detachment of hydrogen atoms from organic molecules adsorbed on the oxide surface; the hydrogen atoms, being transferred into WO3, turn into electrons and protons which migrate then to the CuCl film forming sensitizing centres oil the halide surface being illuminated simultaneously with the illumination of the WO3 Surface. This in turn gives rise to photolysis in the CuCl films, which does not occur without the hydrogen sensitization. The nanosized WO3 film makes it possible to trigger two famous surface photochemical reactions, first proton-coupled electron transfer between the hydrogen-donor molecules and the oxide surface, and then the photolysis of the halide, which radically changes the optical parameters of both the WO3 and the CuCl films. (C) 2009 Elsevier B.V. All rights reserved.