Engineered silver TiOx/TiO2 nanoparticles

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isible-light active materials are sought in photocatalysis and solar energy utilization. Here a material architecture active under visible-light and comprising of titanium suboxide (e.g. Ti4O7, Ti3O5) layers onto nanosilver on nanostructured TiO2 is formed by flame aerosol technology. Abundant combustion intermediates present during flame synthesis of these materials partially reduce TiO2 and induce strong metal-support interactions resulting in crystalline Ti-suboxides as determined by X-ray diffraction. The growth of such suboxides can be controlled through their flame spray synthesis conditions allowing for tuning the light absorption intensity in the visible spectrum. The as-prepared Ti-suboxides are stable upon annealing in air, at least, up to 350 oC for two hours. Their presence on the Ag/TiO2 particle surface and efficiency in generating photoinduced charge separation under visible light is demonstrated by electron paramagnetic resonance spectroscopy. Under visible light (λ > 400 nm), these nanoparticles exhibit strong photo-reduction of cationic species (Cr6+) and photo-oxidation of organics (methylene blue).

Recent, relevant references:

Fujiwara, K.; Deligiannakis, Y.; Skoutelis, C. G.; Pratsinis, S. E., "Visible-light active black TiO2-Ag/TiOx particles", Appl. Catal. B-Environ., 154–155, 9-15, (2014).

Picture Kakeru Research
(a) Commercial (P25) and FSP-made TiO2 loaded with Ag (10 or 20 wt.%) prepared at low (X/Y = 3/5) and high (8/5) temperature and Ti concentration. (b) STEM image and EDX analysis of 20Ag/TiO2 made at X/Y = 3/5. Positions (c-e) for EDX analysis are marked in the STEM image. (f) TEM image of 20Ag/TiO2 made at X/Y = 8/5 with selected (g) high-resolution images. The blue arrows and red broken lines indicate disordered titanium oxide onto nanosilver and TiO2. (e) Schematic of titanium suboxide onto nanosilver and TiO2 created by strong metal-support interactions.
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Wed Jun 28 07:06:37 CEST 2017
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