CeO 2 is a promising catalyst for the HCl oxidation (Deacon process) in order to recover Cl 2 . Employing shape-controlled CeO 2 nanoparticles (cubes, octahedrons, rods) with facets of preferential orientations ((100), ( 111), ( 110)), we studied the activity and stability under two reaction conditions (harsh: Ar:HCl:O 2 = 6:2:2 and mild: Ar:HCl:O 2 = 7:1:2). It turns out that both activity and stability are structuresensitive. In terms of space time yield (STY), the rods are the most active particles, followed by the cubes and finally the octahedrons. This very same trend is reconciled with the complete oxygen storage capacity (OSCc), indicating a correlation between the observed activity STY and the OSCc. The apparent activation energies are about 50 kJ/mol for cubes and rods, while the octahedrons reveal an apparent activation energy of 65 kJ/mol. The reaction order in O 2 is positive (0.26−0.32). Under mild reaction conditions, all three morphologies are stable, consistent with corresponding studies of CeO 2 powders and CeO 2 nanofibers. Under harsh reaction conditions, however, cubes and octahedrons are both instable, forming hydrated CeCl 3 , while rods are still stable. The present stability and activity experiments in the catalytic HCl oxidation reaction over shape-controlled CeO 2 nanoparticles may serve as benchmarks for future ab initio studies of the catalyzed HCl oxidation reaction over well-defined CeO 2 surfaces.

Mesoporous niobium-doped titanium dioxide fi lms from the assembly of crystalline nanoparticles: study on the relationship between the band structure, conductivity and charge storage mechanism The width of the space charge layer is larger than the particles themselves resulting in a negligible potential diff erence between the surface and the bulk. Due to the small potential diff erence only a low Li+ concentration accumulates at the surface. After doping, band bending makes a larger Li potential diff erence, therefore providing more Li storage at/in the surface. When doping is increased, the width of the space charge layer is reduced, which makes the Li storage at/in the surface decrease. rsc.li/materials-a Registered charity number: 207890 Mesoporous niobium-doped titanium dioxide films from the assembly of crystalline nanoparticles: study on the relationship between the band structure, conductivity and charge storage mechanism †

In this work, we present detailed investigations on the influence of binary ionic liquid (IL) mixtures on sol−gel syntheses of metastable metal oxide phases. The synthesis of the metastable TiO 2 bronze phase and anatase as well as the rutile modification is followed via in situ diffraction methods coupled with thermal gravimetric analysis. The variation of the composition of mixtures of ILs allows for the adjustment of TiO 2 phase composition at low temperatures. On the basis of these results, the synthesis of the hexagonal tungsten bronze-like titanium hydroxyl oxy fluoride was achieved. Our results pave the way for a deeper understanding of IL participation in the syntheses of inorganic nanomaterials, going further than treating them as solvents.

With the aid of ab initio molecular dynamics simulations, we investigate an ionic liquid (IL) mixture composed of three components 1-butyl-3-methylimidazolium [C 4 C 1 Im] + , tetrafluoroborate [BF 4 ] − , and chloride [Cl] − without and with water. In the pure IL mixture, we observe an already complex network of interactions between cations and anions, and addition of water to the system even extends the complexity. Observed number integrals show that the coordination number between cations and anions is reduced in the system with water compared to that in the pure system. Further studies show that the Coulombic network of the strongly coordinating anion [Cl] − is disturbed by water, while that of the weakly coordinating anion [BF 4 ] − is not. These observations can also be confirmed by the Voronoi polyhedra analysis, which shows that the polar network of microheterogeneous IL collapses by the introduction of water. Hydrogen-acceptor interactions revealed that the [Cl] − anions are transferred from being situated in the IL to the water continuum, while [BF 4 ] − is almost unperturbed; these effects mainly influence the interplay of the ionic liquid network.

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