Synergistic effect of Pt0 and M2+ (Cu2+, Ni2+, Co2+) on photo(electro)catalytic activity of TiO2 nanorod array thin films

• TiO2 nanorod array thin films were prepared by the hydrothermal method and modified with M2+ (Cu2+, Ni2+, Co2+) by ultrasonic assisted sequential cation adsorption method.
• Effect of Pt0 adding to M2+-TiO2 nanorod array thin films was investigated.
• I–V curves and photocatalytic activities were investigated.
• Cu2+-TiO2/FTO showed 95.93 μA/cm2 photocurrent density while Pt0-Cu2+-TiO2/FTO showed 760.80 μA/cm2.
• Enhanced photocurrent density was achieved by Pt0-Ni2+-TiO2/FTO as approximately 1.36 mA/cm2. Pt0-Ni2+-TiO2/FTO showed 2.2 times higher quantum yield in photocatalytic methylene blue degradation with respect to pure TiO2/FTO.

M2+ (Cu2+, Ni2+, Co2+) and Pt0-M2+ loaded TiO2 nanorod film samples were prepared on transparent conducting oxide glass (FTO/F:SnO2). Two step method was used consisting a hydrothermal method to grow TiO2 nanorods on the surface and an ultrasonic-assisted sequential cation adsorption method to modify the nanorods. The samples were characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (DRS), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy. The photoelectrochemical properties of the samples were evaluated by linear sweep voltammetry, photocatalytic activities were tested by methylene blue degradation under visible light. M2+-TiO2/FTO samples were compared with Pt0-M2+-TiO2/FTO samples; the synergistic effect of Pt0 and M2+ was discussed. Pt0-Ni2+-TiO2/FTO showed superior photoelectrocatalytic activity with 1.358 mA cm−2 and 78.3% methylene blue degradation under visible light. Quantum yields were calculated separately as a sign for H2 generation rate and as a conversion of methylene blue molecule per absorbed light.