Photohole Trapping Induced Platinum Cluster Nucleation on the Surface of TiO2 Nanoparticles

The photocurrent response of TiO2 nanoparticles synthesized via the sol–gel process was studied in the presence of methanol, ethanol, and isopropanol. The nanocrystalline nature of photoelectrodes showed an important photocurrent in the presence of alcohol following the order methanol ≈ ethanol > isopropanol > H2O. This process mimics the photoelectrochemical response, and therefore a correlation of the photodeposition process of platinum nanoclusters on TiO2 particles in the presence of alcohol molecules was devised. The photodeposition mechanism of platinum nanoislands at the surface of a nanocrystalline TiO2 powder is discussed in the light of the photoelectrochemical results.