Specific Facets-Dominated Anatase TiO2: Fluorine-Mediated Synthesis and Photoactivity

Abstract

Semiconductors crystal facet engineering has become an important strategy for properly tuning and optimizing both the physicochemical properties and the reactivity of photocatalysts. In this review, a concise survey of recent results obtained in the field of specific surface-oriented anatase TiO 2 crystals preparation is presented. The attention is mainly focused on the fluorine-mediated hydrothermal and/or solvothermal processes employed for the synthesis and the assembly of anatase micro/nanostructures with dominant {001} facets. Their peculiar photocatalytic properties and potential applications are also presented, with a particular focus on photocatalysis-based environmental clean up and solar energy conversion applications. Finally, the most promising results obtained in the engineering of TiO 2 anatase crystal facets obtained by employing alternative, possibly more environmentally friendly methods are critically compared.

Foitit-magneziofoitit a rózsa-hegyi ércesedésből, avagy a nagybörzsönyi turmalin újravizsgálata

“…A legtöbb lelőhelyen az anatáz {101} szerinti meredek dipiramisos kristályokat alkot, melyeken legfeljebb csak kis méretben fejlődnek ki a {001} bázislapok. Ennek oka, hogy a termodinamikailag leg stabilabb anatázkristályokon a B/A lenyesési arány (az A és B kristályélek értelmezését lásd a 3. ábrán) jellemző értéke 0,3-0,4 között mozog (DOZZI & SELLI 2013). Ez az érték a nagybörzsönyi anatázra (a 3. ábrán mért élhosszak alapján) 0,88, ami a jól fejlett {001} formának köszönhető.…”

“…Ezt LONDON (2011) is meg erő -sítette, aki szerint a turmalin stabilitása neutrális vagy savas oldatokra korlátozódik; magas alkalinitás mellett a turmalin instabil, helyette albit és Na-amfibolok képződnek. Ilyen formán a nagybörzsönyi turmalin is savas kémhatású hidrotermás oldatból vált ki, melyet még az anatáz morfológiája is megerősít, mivel lúgos oldatokból képződött anatázon az {100} forma lapjai is megjelennek (DOZZI & SELLI 2013), melyeket a nagybörzsönyi anatázon nem figyeltünk meg.…”

Effective Electrons Transfer Pathway of the Ternary TiO₂/RGO/Ag Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

“…[1,2] TiO2 photocatalyst is acknowledged as the most suitable material due to its excellent adjustable microstructure, chemical stability, non-toxicity, easy practicality and low cost. [3][4][5][6] However, there are still some defects mainly concentrating in the high recombination rate of photogenerated carriers and only absorbing UV light. The usual way for overcoming these shortcomings is coupling with sensitizing agents, narrow-bandgap semiconductor, and non-metal-doping or with noble metal materials.…”

CNT-TiO2−δ Composites for Improved Co-Catalyst Dispersion and Stabilized Photocatalytic Hydrogen Production

“…One of the key issues in solar water-splitting is the development of efficient and stable systems for light-driven reduction of protons to hydrogen. Among other materials, titanium dioxide (TiO2) is comprehensively studied as a photocatalyst for hydrogen production due to its relatively negative position in the conduction band edge allowing for proton reduction, low cost, high stability and the possibility of further functionalization [3][4][5][6][7][8].…”