Effect of synthesis method parameters on properties and photoelectrocatalytic activity under solar irradiation of TiO2 nanotubes decorated with CdS quantum dots

The growing research interest on photoelectrocatalysis has encouraged the search for new materials with high activity and the development of methods for their synthesis. The successive ionic layer adsorption and reaction (SILAR) method is an effective way to synthesize materials with photoelectrocatalytic (PEC) properties that are active under visible radiation. Therefore, studies on the impact of the parameters of the SILAR method on the properties and PEC activity of TiO2 nanotubes sensitized with CdS quantum dots (QDs) were conducted. PEC activity was determined based on the efficiency of ifosfamide (IF) degradation, which is currently one of the most commonly detectable anticancer drugs in aquatic environment. The highest IF PEC degradation rate (0.0184 min(-1)) and the highest TOC removal (48%) was achieved with the CdS-Ti/TiO(2)(-)(-)NO(3)(-)(-)0.1M(-)(-)3c(-)(-)60s photoelectrode. Among the SILAR parameters, the highest impact on the PEC IF degradation efficiency had the concentration of the Cd precursor, as well as the number and time of the cycles. Our studies showed that CdS-Ti/TiO2 nanocomposites exhibited more than twice higher photocatalytic and PEC IF degradation efficiency than pristine Ti/TiO2 under UV-Vis irradiation. In addition, the PEC mechanism of IF degradation using pristine Ti/TiO2 and CdS-Ti/TiO2 was compared, from which it was concluded that the higher PEC activity of the nanocomposites is due to the greater contribution of h(+) and the generation of other oxidants caused by the presence of CdS QDs. Based on the identified degradation products, a pathway for PEC IF degradation was also proposed.