Pt/GZO hybrid nanocomposites were formed by depositing Pt nanoparticles (NPs) using an atomic layer deposition (ALD) technique onto one-dimensional (1D) Ga-doped ZnO (GZO) nanopagodas (NPGs). The GZO NPGs were prepared by metal-organic chemical vapor deposition (MOCVD). The ALD deposited Pt NPs were well-dispersed and uniform on the surfaces of the GZO NPGs, which were much better than Pt NPs prepared by conventional wet chemistry methods. Pt/GZO hybrid nanocomposites with 30 ALD cycles exhibited significant improvement in photocatalytic activity by about 2.7 times higher than GZO NPGs under 254 nm UV illuminations. The effect of Pt NPs on photocatalytic activities of Pt/GZO hybrid nanocomposites was discussed using various photocatalytic mechanisms. Due to the competing effects of decorated Pt NPs on absorbance/transmittance, electron-hole separation/recombination, and the local surface plasmon resonance, there exists an optimal Pt NPs loading content, which exhibits a maximal photocatalytic activity of 1D Pt/GZO hybrid nanocomposites. (C) 2014 Elsevier B.V. All rights reserved.