Here I report on the degradation of dimethylformamide on the surface of the nanosized WO3 films under the action of light. Dimethylformamide, a substance that has a series of interesting properties, was adsorbed on the surface of the WO3 films and its adsorption mechanism and transformations under the action of light have been investigated with the help of the IR spectroscopy. The spirit of the research is that both DMF modifications have been used i.e., conventional and that with the substitution of hydrogen atoms by deuterium. Formation of two weak bonds (donor -acceptor bond and hydrogen bond) provides a great catalytic effect for photo -initiated proton -coupled electron transfer from the adsorbed molecules to the WO3 film surface. The mechanism of the detachment of hydrogen atoms and subsequent transformation of the adsorbed molecules has been investigated and discussed. (C) 2016 Elsevier B.V. All rights reserved.