Facet‐Dependent Interfacial and Photoelectrochemical Properties of TiO2 Nanoparticles

Abstract The photoelectrochemical properties of titanium dioxide (TiO 2 ) nanoparticles are directly related to the presence of certain facets. The synthesis of such particles is challenged using volatile and sensitive precursors utilizing shape capping agents. In this study, an easier two‐step synthesis technique for the preparation of well‐specified morphology TiO 2 nanocrystals from TiO 2 powder is demonstrated. The facet‐dependent Fermi level and flat band potential of the prepared particles are calculated and their photoelectrochemical properties are investigated by Cu 2+ and Pb 2+ photo/electrodeposition. From Cu 2+ electrodeposition, it is shown that the presence of {100} and {001} facets in cubic morphology facilitates the electrodeposition with progressive nucleation mechanisms, while the presence of {101} facet in octahedral geometry follows instantaneous nucleation mechanisms. The activity of electroreduction is also related to the flat‐band potential which shows the highest activity in Pb 2+ electrodeposition for octahedron nanostructure due to the alignment of the reduction potential to the edge of the flat band. Photodeposition of Cu 2+ and Pb 2+ ions shows identical trends to electrodeposition indicating the facets influence in ion adsorption and structure of the bandgap of morphological TiO 2 . The findings emphasize the importance of facet‐dependent surface adsorption and bandgap structure designing faceted TiO 2 nanoparticles for tailored applications.