Synthesis of Nanostructured Reduced Titanium Oxide: Crystal Structure Transformation Maintaining Nanomorphology†

摘要: There is an increasing need for the synthesis of nanostructured reduced oxides because their attractive properties; example, compared with titanium dioxide (TiO2), are photovoltaics, photocatalysts, and fuel cells owing to narrow band gap enabling absorption visible light, chemical stability, relatively high electrical conductivity, comparable that graphite. Generally, have been synthesized by 1) thermal reduction TiO2 at about 1000 8C H2 gas or Ti powder, 2) photochemical UV laser irradiation, 3) direct from unique precursors using ablation techniques. These reductive techniques in turn cause particle growth compositional inhomogeneity, making it difficult obtain high-quality nanostructures. Ti4O7 Ti8O15 nanowires were annealing H2Ti3O7 a hydrogen atmosphere. [2] nanostructures seem most sophisticated reported so far; however, inevitable method seems be inapplicable other Since significant importance exploiting oxides, development novel synthesizing them on nanoscale needed. Herein we report reducing strong agent much lower temperatures than conventional Interestingly, oxide same morphology as its precursor was obtained, though crystal structure transformed tetragonal hexagonal system. The applicable dioxides, thus opens up fascinating possibilities designing wide range applications. We chose nanoparticles rutile (tetragonal, P42/mnm), which high-temperature phase obtained above 800 irreversibly stable room temperature, precursor. as-received thoroughly mixed fourfold molar excess CaH2 then heated 350 15 d. Low-temperature binary metal hydrides first demonstrated Hayward et al., who used solid NaH topotactically synthesize infinite-layer LaNiO2 perovskite LaNiO3. [11] then, alkali alkaline earth such LiH employed al. others unprecedented phases inaccessible powerful activity even low expected enable us TiO2. final product black powder (see Figure 3), typical oxides. 1 compares synchrotron X-ray diffraction (SXRD) patterns product. After reduction, SXRD significantly changed; all major peaks readily