Rapid breakdown anodization to obtain nanostructured TiO₂ powders for photocatalytic hydrogen generation

TiO₂ is widely used for photocatalytic applications, and several methodologies are employed to obtain nanostructured TiO₂ powders with a wide range of morphologies that tune its performance; however, rapid breakdown anodization methodology has been scarcely explored for this purpose, disregarding the impact of processing variables over TiO₂ properties and photocatalytic performance. Here, the synthesis of TiO₂ nano-powders at different voltages (10, 15, 20 and 25 V) and their performance in the UV-photocatalytic water decomposition for hydrogen generation are reported. SEM images showed that TiO₂ powders consisted of uniformly distributed nanoparticles, disregarding the voltage employed for their growth; however, the crystallinity, specific surface area and semiconducting properties were considerably affected. The highest H₂ generation rate in a 7-h test was observed for the powders obtained at 20 V, which showed the most negative flat-band potential and the lowest charge-transfer resistance.