ZnO nanomaterials were successfully prepared by three different methods.

Different preparation method, fuels and different molar ratio of citric acid fuel modified optical properties of ZnO.

The catalytic activity of ZnO nanomaterials was evaluated using dye method for decomposition of Remazol Red RB 133.

The highest photocatalytic activity is found in a gel precursor containing citric acid in the molar ratio of 1.