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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.

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Bimetallic catalysts can undergo segregation or redistribution of the metals driven by oxidizing and reducing environments. Bragg coherent diffraction imaging (BCDI) was used to relate displacement fields to compositional distributions in crystalline Pt-Rh alloy nanoparticles. 3D images of internal composition showed that the radial distribution of compositions reverses partially between the surface shell and the core when gas flow changes between O2 and H2. Our observation suggests that the elemental segregation of nanoparticle catalysts should be highly active during heterogeneous catalysis and can be a controlling factor in synthesis of electrocatalysts. In addition, our study exemplifies applications of BCDI for in situ 3D imaging of internal equilibrium compositions in other bimetallic alloy nanoparticles.