Mixed-phase nanoTiO 2 materials attract a lot of attention as advanced photocatalysts for water decontamination due to their intrinsic structure that allows better photo-excited e − cb -h + vb charge separation, hence improved photocatalytic efficiency. Currently, the best-known mixed-phase TiO 2 photocatalyst is P25 with approximate composition 80% Anatase/20% Rutile (A /r ). Apart from Anatase (A) and Rutile (R) phases, there is Brookite (B) which has been evaluated less as photocatalyst in mixed-phase nanoTiO 2 systems. In this work we present a sustainable solution process to synthesize tunable composition mixed-phase nanotitania photocatalysts in a continuously stirred tank reactor (CSTR) by modulating conditions like pH, C TiCl4 and time. In particular three mixed-phase TiO 2 nanomaterials were produced, namely one predominantly anatase with brookite as minor component (A /b ), one predominantly brookite with minor component rutile (B /r ), and one predominantly rutile with minor component brookite (R /b ) and evaluated as photocatalysts in the degradation of methyl orange. The three semiconducting nanomaterials were characterized by XRD and Raman spectroscopy to quantify the phase ratios and subjected to nano-morphological characterization by FE-SEM and TEM/HR-TEM. The new mixed-phase nanoTiO 2 materials are shown to be endowed with large specific surface area, ranging from 90-125 m 2 g −1 , double of that of P25, to be mesoporous and be surface-rich in Ti-OH molecular groups varying from 12%-20% versus 4% for P25. These properties though impact the adsorptive capacity with R /b and B /r removing > 50% of MO but not photocatalytic activity. The latter depends on nanograined mixed-phase structure and not mere assembly of different phase nanoparticles. First-order rate constants reveal essentially equivalent photocatalytic activity for anatase nanocrystals with either rutile (P25) or brookite (this work) domains.

No abstract

No abstract

Nano-sized mixed-phase titanium dioxide (TiO2) particles are synthesized through aqueous hydrolytic precipitation of TiCl4, in an easily-scalable continuously stirred tank reactor, CSTR. Different conditions give tunable mixed phase nanotitania particles consisting of anatase (A), rutile (R) or brookite (B) that are further characterized as photocatalysts in both oxidative and reductive roles and compared with the well-known commercial nanotitania, Evonik P25. Degradation of an organic model compound, methyl orange under UV light irradiation using the newly synthesized TiO2 blends is first investigated. Further, the remediation of selenium inorganic species from simulated waste water is tackled. Selenium (Se) is an element of environmental concern, as it may report to natural waters via industrial effluents as those released from mining and metallurgical operations among other.

A green, sustainable hydrolytic precipitation process is used to synthesize different blends of intrinsically heterostructured (mixed phase) titanium dioxide (TiO2) nanoparticles (NPs). NPs are evaluated for the decontamination of organic and inorganic pollutants. The NPs are characterized for their morphological, semiconductor and photocatalytic properties. As organic compound, methyl orange was used to evaluate the mixed phase TiO2 NPs through adsorption and photo-oxidation, while selenium (IV and VI) species were the inorganic pollutants of interest, removed by adsorption and photo-reduction. A comparative assessment of photocatalytic effectiveness of different nanoTiO2 varieties is presented revealing contrasting behavior between organic and inorganic removal, while exemplifying the importance of tuning phase composition, as per intended application.