Black TiO2 Synthesis by Chemical Reduction Methods for Photocatalysis Applications

Abstract

Applications of TiO 2 nanomaterials in photocatalysis, batteries, supercapacitors and solar cells, have seen widespread development in recent decades. Nowadays, black TiO 2 have won attention due to enhancing the solar light absorption by the formation of oxygen vacancies and Ti 3+ defects, to promote the separation of photo-generated charge carriers leading to the improvement of the photocatalytic performance in H 2 production and pollutants degradation. The enhanced photocatalytic activity of black TiO 2 is also due to a lattice disorder on the surface and the presence of oxygen vacancies, Ti 3+ ions, Ti-OH and Ti-H groups. Enhancing the optical absorption characteristics of TiO 2 and change of energy level and band-gap of materials have been successfully demonstrated to improve their photocatalytic activities, especially for black TiO 2 nanoparticles, which promote visible light absorption. The current review focuses on the investigation of the chemical reduction synthetic route for black TiO 2 nanomaterials, and their proposed association with green applications such as photodegradation of organic pollutants and photocatalytic water splitting. The synthesis methods of black TiO 2 involves the changes from Ti 4+ to Ti 3+ state, into different strategies: (1) The use of highly active hydrogen species such as H 2 , H 2 /Ar or H 2 /N 2 gases, and metal hydrides (NaBH 4 , CaH 2 ), (2) the reduction by active metals such as aluminum, magnesium and zinc, and (3) organic molecules such as imidazole and ascorbic acid.

Synergic Effect of TiO2 Filler on the Mechanical Properties of Polymer Nanocomposites

“…TiO 2 is found in many applications due to its good photocatalytic properties, hence it is used in antiseptic and antibacterial compositions, degrading organic contaminants and germs, as a UV-resistant material; this is due to its chemical inertness properties, non-toxicity, low cost, high refractive index, and other advantageous surface properties. In these applications, TiO 2 is used as a component of various types of nanocomposite materials with special properties, which open up opportunities in the following various fields of applicability: in the production of pharmaceuticals, cosmetics or paints [ 25 ], drug delivery systems with controlled release [ 26 ], solar cell [ 27 ], chemical sensing, luminescent material, and photocatalyst [ 28 ]. For example, as materials for obtaining membranes for integration in environmental applications, including water treatment or reducing humidification [ 29 , 30 ].…”

Opto-Electronic Characterization of Photocatalysts Based on p,n-Junction Ternary and Quaternary Mixed Oxides Semiconductors (Cu2O-In2O3 and Cu2O-In2O3-TiO2)

“…This is the reason why, whatever the intended use, the formation of p,n-heterojunction systems is considered a smart strategy to improve copper oxides' properties and taking the best from them and from their combination with n-type partners [43,44,46]. As for photocatalytic application, the latter are mainly implied in performing oxidation reactions [50][51][52][53], and the efficient combination of electronic levels with those of a p-partner, can result in charge separation and stabilization.…”

Highly Ordered TiO2 Nanotube Arrays with Engineered Electrochemical Energy Storage Performances

“…Among these nanomaterials, 1D nanotubes have received more and more attention in the materials field. After the synthesis of carbon nanotubes, the research on highly ordered nanotube structures aroused a great upsurge of interest [ 13 , 14 , 15 ]. Research on TiO 2 nanotubes has also became a hot spot.…”