TiO2 nanoparticles with varied content of Cu doping have been synthesized by sol-gel method with the addition of polyethylene glycol (PEG) as a template. The content of Cu doping significantly influenced the structure and morphology of TiO2 nanoparticles. Increasing content of Cu doping caused a phase transformation of TiO2 crystal from rutile to anatase. As well as the surface morphology of TiO2 nanoparticles also significantly were affected by Cu doping, which the TiO2 particles became more finer due to the Cu content increased. The effect of Cu doping on the photocatalytic activity of TiO2 in degrading methyl violet (MV) dye was investigated. Photocatalysis test results confirmed that the content of Cu doping in the TiO2 photocatalyst significantly affected the photocatalytic activity of TiO2 for photodegradation of MV dye. Increasing content of Cu doping increased the degradation rate of MV dye. The TiO2 photocatalyst with the highest Cu doping content (6.0 wt% Cu) has the best photocatalytic activity than the other TiO2 photocatalyst, that is able to degrade MV dye up to 95% after 120 minutes of photocatalysis treatment with a degradation rate is 0.0214 ppm per minute. The pH of MV solution also influenced the photocatalytic activity of TiO2, which the MV dye solution with higher pH has higher the photodegradation efficiency.

Keywords: Cu doping, methyl violet dye, photocatalytic activity, TiO2 nanoparticle