Green microwave switching from oxygen rich yellow anatase to oxygen vacancy rich black anatase TiO₂ solar photocatalyst using Mn(ii) as ‘anatase phase purifier’

Abstract

Green and rapid microwave syntheses of 'yellow oxygen rich' (YAT-150) and 'black oxygen vacancy rich' (BAT-150) anatase TiO2 nanoparticles are reported for the first time. YAT-150 was synthesized using only titanium(iv) butoxide and water as precursors. The in situ precursor modification by Mn(ii) acetate switched anatase TiO2 from YAT-150 to BAT-150. The entry of Mn(2+) into the crystal lattice of anatase TiO2 paved the way for peak texturing in the existing peak orientations along with the origin of three new anatase TiO2 peaks in the (103), (213) and (105) directions. The as synthesized ultra-small (∼5 nm) yellow and black anatase TiO2 nanoparticles were found to be two fold and four fold more photoactive than the commercially available photocatalyst Degussa-P25 under sunlight illumination.

Antibacterial properties of F-doped ZnO visible light photocatalyst

“…Photocatalysts such as TiO 2 or ZnO activated by UV or/and visible light (Fig. 9) [37][38][39][40][41][42][43][44] as a result of the transfer of an electron from the valance band (VB) to the conduction band (CB). The ROS produced as a result of the photocatalytic reaction will be capable of damaging the cell wall and can decompose the cellular materials (Fig.…”

“…Further modification of the synthesis procedure by controlling the annealing conditions to alter the oxygen stoichiometry under different (e.g., reducing, inert or oxygen rich) atmospheres can possibly lead to the formation of materials with optimum functional properties. Results of physicochemical and biological testing of the doped ZnO materials indicate that these materials will have potential application of in various areas such as photocaltalytic environmental purification, water disinfection, pharmaceutical effluent degradation and energy production and conversion [5,41,43,44].…”

Progress in Black Titania: A New Material for Advanced Photocatalysis

“…[ 97 ] The as-prepared Ti 3+ -self doped black TiO 2 had substantially narrowed bandgap of 1.72 eV, resulting in enhanced visible light harvesting. [ 97 ] …”

“…And the best photocatalytic performance was achieved by the sample with a high surface-to-bulk defect ratio, as shown in Figure 36 . [ 28,30,84,90,91,97,138 ] For example, TiO 2x nanoparticles derived from TiH 2 -H 2 O 2 systems could completely degrade MB within 60 min under visible light, [ 30,84,91 ] and 20 min under solar light, [ 90 ] which is much better than that of the hydrogenated TiO 2 nanosheets. [ 36,43 ] However, defective TiO 2x materials with high concentration of bulk oxygen vacancy/Ti 3+ prepared from solution oxidation methods actually showed outstanding photocatalytic activities, even better than the black titania made by reduction methods which had dominant surface defect.…”

An Amorphous Mn, N-Codoped TiO2 Microspheres Photocatalyst Induced by High Defects with Greatly Extended Visible-Light-Responsive Range for Photocatalytic Degradation

“…Herein, combined with the current research status of photocatalyst, we show that amorphous Mn, N-codoped TiO 2 microspheres used as an effective visible light photocatalyst. [28][29][30][31] Amorphous TiO 2 (0.2 Mn, N -400 °C -2 h) with a narrow bandgap shows an obviously higher photocatalytic activity in degradation of organic dye under visible light than the crystalline counterparts. It is mainly due to the high suspending and adsorption ability, interstitial N doped form and more oxygen vacancies in present photocatalysts.…”