The effects of the polymer precursor in polymerizable complex (PC) method for the preparation of a Sr-Nb mixed oxide photocatalyst were studied. A polymer made of citric acid and ethylene glycol, which is generally applied in the PC method, as well as that made of succinic acid and 2-(2-aminoethylamino)ethanol (AEEA) were used as polymer chelating ligands. The photocatalytic activity of prepared mixed oxides for the overall H2O splitting depended on the oxide crystal structure, which was affected by the chelating complex polymer precursors and the calcination temperature. In particular, the Sr-Nb mixed oxide prepared from succinic acid and AEEA precursors showed the significantly high photocatalytic activity for the overall splitting of H2O after calcination at 973 K. The influences of the origin of polymer precursors to the crystal structure and the composition of the Sr-Nb mixed oxide and its photocatalytic performance to the overall H2O splitting are discussed. (C) 2014 Elsevier B.V. All rights reserved.