Crystal properties without crystallinity? Influence of surface hydroxylation on the structure and properties of small TiO₂ nanoparticles

Abstract

Titania (TiO2) nanoparticles (NPs) are widely employed in applications that take advantage of their photochemical properties (e.g. pollutant degradation, photocatalysis). Here, we study the interrelation between crystallinity, surface hydroxylation and...

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

“…35 The structures of the hydroxylated amorphous (TiO 2 ) 35 NPs were generated by separate simulated annealing runs for each degree of hydroxylation. 30 To compare with our NP based results we also considered a periodic slab model of the (101) anatase surface (see Fig. 1b).…”

“…We employ three previously reported realistic titania NP models with different sizes and crystalinities. 3,16,30 Two of these (TiO 2 ) n NPs, with sizes n = 35, 165, possess the anatase crystal structure with bipyramidal faceted morphologies. We also consider one amorphous (TiO 2 ) 35 NP with a roughly spherical morphology.…”

“…35 The structures of the hydroxylated amorphous (TiO 2 ) 35 NPs were generated by separate simulated annealing runs for each degree of hydroxylation. 30…”

“…Herein, we focus on LIDE in hydroxylated anatase titania NPs using realistic models developed in previous works 16,30 which have been used to rationalise experimental results on hydroxylated anatase NPs. 3 As far as we are aware, hydroxylation induced LIDE for titania has only been previously studied using periodic slab models of ideal surfaces with small numbers of hydrogen atoms placed on oxygen atoms (i.e.…”

Estimating Nonradiative Excited-State Lifetimes in Photoactive Semiconducting Nanostructures

“…36 The design of the titania nanostructures described above follows a top-down strategy analogous to the one reported by some of us. 29,33,65 It starts from a large titania bulk crystal and takes into account that the anatase (101) surface is the most stable one. Hence, one can build bipyramidal (i.e., octahedral morphology) nanoparticles exhibiting just this facet as shown by the (TiO 2 ) 10 , (TiO 2 ) 35 , and (TiO 2 ) 84 nanostructures.…”