The mixture of two surfactants (C 12 EO 10 -CTAB and C 12 EO 10 -SDS) forms lyotropic liquid-crystalline (LLC) mesophases with [Zn(H 2 O) 6 ](NO 3 ) 2 in the presence of a minimum concentration of 1.75 H 2 O per C 12 EO 10 . The metal ion/C 12 EO 10 mole ratio can be increased up to 8.0, which is a record high metal ion density in an LLC mesophase. The metal ion concentration can be increased in the medium by increasing the CTAB/C 12 EO 10 or SDS/C 12 EO 10 mole ratio at the expense of the stability of the LLC mesophase. The structure and some thermal properties of the new mesophase have been investigated using XRD, POM, FTIR, and Raman techniques.

In the current work, TiO 2 /Al 2 O 3 binary oxide photocatalysts were synthesized via two different sol-gel protocols (P1 and P2), where various TiO 2 to Al 2 O 3 mole ratios (0.5 and 1.0) and calcination temperatures (150-1000 • C) were utilized in the synthesis. Structural characterization of the synthesized binary oxide photocatalysts was also performed via BET surface area analysis, X-ray diffraction (XRD) and Raman spectroscopy. The photocatalytic NO(g) oxidation performances of these binary oxides were measured under UVA irradiation in a comparative fashion to that of a Degussa P25 industrial benchmark. TiO 2 /Al 2 O 3 binary oxide photocatalysts demonstrate a novel approach which is essentially a fusion of NSR (NO x storage reduction) and PCO (photocatalytic oxidation) technologies. In this approach, rather than attempting to perform complete NO x reduction, NO(g) is oxidized on a photocatalyst surface and stored in the solid state. Current results suggest that alumina domains can be utilized as active NO x capturing sites that can significantly eliminate the release of toxic NO 2 (g) into the atmosphere. Using either (P1) or (P2) protocols, structurally different binary oxide systems can be synthesized enabling much superior photocatalytic total NO x removal (i.e. up to 176% higher) than Degussa P25. Furthermore, such binary oxides can also simultaneously decrease the toxic NO 2 (g) emission to the atmosphere by 75% with respect to that of Degussa P25. There is a complex interplay between calcination temperature, crystal structure, composition and specific surface area, which dictate the ultimate photocatalytic activity in a coordinative manner. Two structurally different photocatalysts prepared via different preparation protocols reveal comparably high photocatalytic activities implying that the active sites responsible for the photocatalytic NO(g) oxidation and storage have a non-trivial nature.

a b s t r a c tTiO 2 -Al 2 O 3 binary oxide surfaces were utilized in order to develop an alternative photocatalytic NO x abatement approach, where TiO 2 sites were used for ambient photocatalytic oxidation of NO with O 2 and alumina sites were exploited for NO x storage. Chemical, crystallographic and electronic structure of the TiO 2 -Al 2 O 3 binary oxide surfaces were characterized (via BET surface area measurements, XRD, Raman spectroscopy and DR-UV-Vis Spectroscopy) as a function of the TiO 2 loading in the mixture as well as the calcination temperature used in the synthesis protocol. 0.5 Ti/Al-900 photocatalyst showed remarkable photocatalytic NO x oxidation and storage performance, which was found to be much superior to that of a Degussa P25 industrial benchmark photocatalyst (i.e. 160% higher NO x storage and 55% lower NO 2 (g) release to the atmosphere). Our results indicate that the onset of the photocatalytic NO x abatement activity is concomitant to the switch between amorphous to a crystalline phase with an electronic band gap within 3.05-3.10 eV; where the most active photocatalyst revealed predominantly rutile phase together and anatase as the minority phase.

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a b s t r a c tThe mixtures of [Zn(H 2 O) 6 ](NO 3 ) 2 salt, 10-lauryl ether (C 12 H 25 (OCH 2 CH 2 ) 10 OH, represented as C 12 EO 10 ), a charged surfactant (cetyltrimethylammonium bromide, C 16 H 33 N(CH 3 ) 3 Br, represented as CTAB or sodium dodecylsulfate, C 12 H 25 OSO 3 Na, SDS) and water form lyotropic liquid crystalline mesophases (LLCM). This assembly accommodates up to 8.0 Zn(II) ions (corresponds to about 80% w/w salt/(salt + C 12 EO 10 )) for each C 12 EO 10 in the presence of a 1.0 CTAB (or 0.5 SDS) and 3.5 H 2 O in its LC phase. The salt concentration can be increased by increasing charged surfactant concentration of the media. Addition of charged surfactant to the [Zn(H 2 O) 6 ](NO 3 ) 2 -C 12 EO 10 mesophase not only increases the salt content, it can also increase the water content of the media. The charged surfactant-C 12 EO 10 (hydrophobic tail groups) and the surfactant (head groups)-salt ion (ion-pair, hydrogen-bonding) interactions stabilize the mesophases at such salt high and water concentrations. The presence of both Br À and NO