Titanium Dioxide Derived Materials with Superwettability

Abstract

Titanium dioxide (TiO2) is widely used in various fields both in daily life and industry owing to its excellent photoelectric properties and its induced superwettability. Over the past several decades, various methods have been reported to improve the wettability of TiO2 and plenty of practical applications have been developed. The TiO2-derived materials with different morphologies display a variety of functions including photocatalysis, self-cleaning, oil-water separation, etc. Herein, various functions and applications of TiO2 with superwettability are summarized and described in different sections. First, a brief introduction about the discovery of photoelectrodes made of TiO2 is revealed. The ultra-fast spreading behaviors on TiO2 are shown in the part of ultra-fast spreading with superwettability. The part of controllable wettability introduces the controllable wettability of TiO2-derived materials and their related applications. Recent developments of interfacial photocatalysis and photoelectrochemical reactions with TiO2 are presented in the part of interfacial photocatalysis and photoelectrochemical reactions. The part of nanochannels for ion rectification describes ion transportation in nanochannels based on TiO2-derived materials. In the final section, a brief conclusion and a future outlook based on the superwettability of TiO2 are shown.

Recent advances in photocatalytic self-cleaning performances of TiO2-based building materials

“…The contact angle of the hydrophilic surface is generally less than 90°, while that of the super-hydrophilic surface can reach below 10°, or even almost 0°. 18 This surface makes the water tend to spread at on the surface, forming a uniform water lm that can block dirt and Fig. 1 Principle of photocatalytic self-cleaning on TiO 2 surface.…”

CO2 laser additive manufacturing of multi-layer heterogeneous transparent films using TiO2 and SiO2 nanoparticles

“…The optical and microstructural properties of the sintered SiO2 thin films can be improved by an adapted annealing procedure, as investigated in [10][11][12] . The transformation of TiO2 and SiO2 phases depends on the growth process of NPs in the multilayer films, and this transformation depends on the size and concentration of NPs in the initial nanosuspension and the particle packing density 13 . The change in the optical properties; especially the refraction index, is influenced by the composition and the percentage of TiO2 and SiO2 NPs in the heterogenous films.…”

Hierarchical ‘rose-petal’ ZnO/Si surfaces with reversible wettability reaching complete water repellence without chemical modification

“…Reversible wettability has been demonstrated in titanium dioxide (TiO 2 ), zinc oxide (ZnO), tin dioxide (SnO 2 ), tungsten trioxide (WO 3 ), vanadium pentoxide (V 2 O 5 ), and others. This effect is based on the common mechanism of a switching surface chemical environment between two states, a hydrophilic one due to hydroxy groups on the surface and a hydrophobic one due to replacement of hydroxy groups by oxygen atoms [16,17]. Among them, ZnO is a low-cost material with chemical and thermal stability, photocatalytic activity, and other useful physical and chemical properties, and it is actively used in the field of biomimetic surfaces [18][19][20][21].…”