Large scale synthesis of V-shaped rutile twinned nanorods

Abstract

. (2012). Large scale synthesis of V-shaped rutile twinned nanorods. CrystEngComm, 14 (9), 3120-3124.Large scale synthesis of V-shaped rutile twinned nanorods Abstract V-shaped rutile twinned nanorods (VRTNs) with different aspect ratios were synthesized on large scale using a one-pot organic solvothermal method. Although several different types of VRTNs were produced, (101) twinned nanorods were the major product with minor amounts of (301) twins and straight nanorods. STEM, TEM and XRD characterizations show that [001] is the growth direction of VRTNs, with surfaces dominated by {110} facets. Intermediate formation of both brookite and anatase nanorods provides dual pathways to VRTNs' growth: one path in which anatase seeds trigger and promote brookite nanorod growth; and a second path in which anatase nanorods are formed by oriented attachment. Subsequent dissolution of both brookite and anatase nanorods provides titania to support VRTNs growth. V-shaped rutile twinned nanorods (VRTNs) with different aspect ratios were synthesized on large scale using a one-pot organic solvothermal method. Although several different types of VRTNs were produced, (101) twinned nanorods were the major product with minor amounts of (301)

Self-assembly of multilevel branched rutile-type TiO2 structures via oriented lateral and twin attachment

“…The angle of ~45° measured from the TEM image corresponds to a complementary angle between (110) R1 ∢ (110) R2 ≡ 134.9°, which is produced by 180° rotation around the (101)-plane normal. This operation generates (101) twin with the characteristic angle between the c-axis of 114.4°, and complementary at 65.6° 18 19 20 45 47 . EDPs recorded on the primary crystal and the branch, shown in Fig.…”

“…For replacement reaction to take place we would need a crystalline precursor phase with structurally related sublattice that is transformed into rutile 46 47 48 . Indeed, under some synthesis conditions, the twins have a single nucleation point, suggesting that they form during nucleation of rutile 40 43 44 45 . Under our experimental conditions the first precipitate is fibrous rutile with amorphous titania and minor anatase.…”

“…Common to these studies is that branching of rutile appears to be inversely proportional to the acidity of the medium; where in less acidic medium the hydrolysis of the titanium (IV) precursor is believed to be more intense 16 , leading to forceful nucleation and formation of rutile microspheres, whereas under more extreme acidic conditions branched structures are evolved. The branching has been described by different attachment/twinning laws, including {111} 16 , {200} 18 , {110} 18 29 , {101} 17 18 19 20 43 44 45 , and {301} 44 45 , out of which the most important element of branching is twinning. It involves simple geometric operations that bring two or more crystals of the same phase into special orientations that are not possible by random intergrowths.…”

Twinning-mediated anomalous alignment of rutile films revealed by synchrotron X-ray nanodiffraction

“…As an important class of multifunctional materials, rutile TiO 2 can be twinned on (101) and (301) planes ( Hwang et al., 2000 ; Li et al., 1999 ; Lu et al., 2012a , 2020a ; Jordan et al., 2018 ; Gao et al., 1992 ; Daneu et al., 2007 , 2014 ). However, the synthetic TiO 2 twins generally possess lower texture because twinning trends to alter the growth direction or crystal orientation, which is detrimental to practical applications and the discovery of novel properties, whereas the natural rutile twin minerals can directionally form on their substrates ( Li et al., 1999 ; Lu et al., 2012a ; Jordan et al., 2018 ; Gao et al., 1991 , 1992 ; Daneu et al., 2007 , 2014 ; Lee et al., 2006 ; Sosnowchik et al., 2010 ). Recently, we have successfully synthesized rutile TiO 2 nanotwin films on fluorine-doped tin oxide (FTO) glass substrates with the rare b -axis preferred orientation (instead of the c -axis in common self-aligned rutile films) via a rapid nucleation/twinning strategy ( Lu et al., 2020a ).…”

Direct oxygen imaging in titania nanocrystals

“…We have previously developed an approach to produce rutile nanotwins using high temperature organic solvent methods: two kinds of common high-quality rutile twinned nanocrystals, (101) and (301) twins, accompanied by minor rutile nanorods [1]. In this paper, the atomic structures of the rutile and anatase nanocrystals are directly resolved with no need for calculation or image simulation using atomic resolution STEM techniques.…”