Variations of electronic properties on the behavior of visible light-triggered TiO[sub]2 +Au photocatalysts

Au catalysts (1 wt% Au) using anatase TiO2 nanorods (TNR, SBET =106 m2/g) or nanospheres (TNP, SBET =86 m2/g). The majority of Au particles in the prepared TiO2 +Au catalysts were in the range of 20–30 nm, with slight differences observed between the TNR +Au and TNP +Au samples. It is noteworthy that the addition of Au did not significantly change the specific surface area and crystallinity of the TiO2 supports. Evaluation of photocatalytic activity using ABTS•+ cation oxidation, DMPO/DMSO spin trapping and bisphenol A (BPA) degradation under visible-light illumination showed different behaviour of TNR +Au and TNP +Au catalysts. The TNR +Au catalyst produced mainly e-, while the TNP +Au catalyst exhibited efficient O2 •- production, which was confirmed by electron paramagnetic resonance spin trapping analyses. Conversely, due to its high Schottky barrier height (SBH) and the properties of the Au nanoparticles, the TNR +Au catalyst could not facilitate an oxygen reduction reaction but effectively produced e- as it reduced ABTS•+. The results show that the degra dation of BPA in the presence of the TNR +Au photocatalyst occurs through the involvement of e- and a small amount of hydroxyl radicals (OH•). Comprehensive characterization techniques provided insights into the intricate relationships between catalyst structure, composition and catalytic activity.