Photocatalytic carbon dioxide (CO2) conversion into carbon monoxide (CO) using H2O as an electron donor was achieved by the strontium titanate (SrTiO3: STO) nanorod thin films loaded with amorphous copper oxide (CuxO) nanoclusters. The loading of the CuxO-cocatalysts onto STO nanorods clearly improved the photocatalytic activity compared to bare STO nanorods. The CuxO-cocatalysts are composed of abundant and non-toxic elements, and can be loaded by using a simple and economical method. Our findings demonstrate that CuxO nanoclusters function as a general cocatalyst and can be used in combination with various semiconductors to construct low-cost and efficient photocatalytic CO2 reduction systems. (C) 2016 Elsevier B.V. All rights reserved.