Nanocomposite films consisting of TiO2 and Zn with thickness of 10-15 mum (TiO2-Zn) have been electrodeposited on steel plates by rapid plating from a ZnSO4-based bath (I-d > 10 A dm(-2)). Upon addition of NH4NO3 to the bath (<0.3 g L-1), the uptake of TiO2 in the film significantly increased. Glow discharge optical emission spectrometry clarified that TiO2 particles were incorporated throughout the film and the loaded amount increased near the surface. The first-order rate constant (k/h(-1)) for gas-phase CH3CHO oxidation was employed as an indicator of the photocatalytic activity. The k value for the TiO2-Zn film prepared at I-d = 12 A dm(-2) (0.20 h(-1)) was comparable to that for the sample from a ZnCl2-based bath at I-d = 4 A dm(-2) (0.27 h(-1)). X-ray diffraction measurements indicated that a TiO2-ZnO nanocomposite layer was generated on the surface by the heat treatment in air at 673 K for 6 h. Consequently, the photocatalytic activity was further improved (k = 0.29 h(-1)); this effect was explained in terms of the synergy of TiO2 and ZnO in photocatalysis. (C) Kluwer Academic Publishers.