Photocatalytic and electrooxidation properties of TiO2 thin films deposited by sol–gel

• Anatase TiO2 thin films were grown on glass substrates via sol–gel at 400–600 °C.
• 150-nm-thick TiO2 films show remarkable photocatalytic activity under UV-A exposure.
• Methanol electrooxidation is notably improved under UV-A exposure (IPCE = 88.3%).

Anatase TiO2 thin films are deposited on glass using alcoholic solutions at 400–600 °C. The effect of film thickness, grain size and annealing temperature on the catalytic activity of the TiO2 thin films is investigated regarding the degradation of octadecanoic (stearic) acid under UV-A light illumination. Specifically, the photocatalytic activity of 150-nm-thick TiO2 thin films deposited on glass at 500 °C is quite remarkable, showing the highest octadecanoic acid disappearance rate, i.e., 6.28 × 10−8 mol/min (formal quantum efficiency = 6.65 × 10−3) at 30 min of UV-A light illumination. Moreover, the electrochemical performance of the same sample is evaluated by studying the electrocatalytic oxidation of methanol in an alkaline medium in dark and under UV illumination. Under UV illumination, the methanol electrooxidation is significantly improved, as evidenced by the current–potential measurements presenting a satisfactory incident photon to charge carrier efficiency of 88.3% with a fill factor of 0.51.

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