The present work focuses on the deposition of Cu, Co, Mn and Mo doped zinc oxide thin films onto glass substrates and investigates their photocatalytic dye degradation abilities at different pH values of the test dye solution. The effect of point of zero charge on the photocatalytic activity was studied. This study demonstrates how the pH of the dye solution plays a crucial role on the dye degrading mechanism. The optimum pH for achieving the best dye degrading efficiency was estimated for all the four doped ZnO films for cationic dyes and the procedure for extending this idea to the anionic dyes was also addressed.
