The efficiency of photo-oxidation of pollutants catalysed by semiconductors is still limited for real-world applications due to several drawbacks, such as a) insufficient absorption of visible radiation, which predominates in solar spectrum, b) rapid free electron to hole recombination, c) small surface area, built from equilibrium crystallographic facets with low adsorption capacities and d) photo-corrosion. The present study disclosures new mesoporous heterostructures, built from exfoliated lepidocrocite-like ferrititanates and TiO 2 (anatase)-acetylacetone charge transfer complex, capable of reducing free electron-to-hole recombination rate through a robust charge separation and sensitive to the visible light spectrum. The synthesis route is based on soft-chemistry and low temperature calcination at 300°C. Two different partially pillarized heterostructures, denoted as HM-1 and HM-2, have been synthesized. It was observed that the heterostructure HM-1 was four times more active toward photocatalytic degradation of NO gas in comparison to the benchmark photocatalytic material P25. The lower activity of the heterostructure HM-2, comparable to that of P-25, was attributed to the high value of Urbach energy that indicates high number of defect sites within energy band-gap of the constituent semiconductor components. [Ti] anatase/[Ti] ferrititanate mol ratio might also play a role in photocatalytic efficiency.

No abstract

No abstract

No abstract

Ceramic materials from the A2M3O12 family with near‐zero thermal expansion are good candidates for applications requiring high thermal shock resistance. Considering their inherently low thermal conductivity, the bulk forms of A2M3O12 have to present Young's moduli and mechanical strength close to 100 GPa and 100 MPa, respectively, in order to compete with the state‐of‐the‐art materials used to avoid thermal shock. The relationship between sintering, microstructure, and physical properties within the A2M3O12 family is generally unknown while the preparation of bulks with high mechanical resistance remains a great challenge. Bulk samples of dense Al2W3O12 (96%TD) have been obtained by pressureless three‐stage sintering (TSS) and spark plasma sintering (SPS). The Young's moduli and hardness of samples prepared by SPS were 50% higher than that measured for TSS samples and more than 100% in comparison to the Al2W3O12 bulk (91%TD). UV‐Vis spectroscopy confirmed that A2M3O12 phases are wide band‐gap semiconductors (3.11 eV). When prepared by SPS, black Al2W3O12 absorbed light within the visible spectrum due to the introduction of donor sites within the band‐gap. No enhancement of the mechanism causing negative thermal expansion was observed for black Al2W3O12. The mechanical properties achieved were significantly improved over those previously reported in literature for Al2W3O12.