Tuning TiO₂nanoparticle morphology in graphene–TiO₂hybrids by graphene surface modification

Abstract

We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shape and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted truncated bipyramids, bonded to graphene via the {100} facets. Belted trunc ated bipyramids formed on unfuctionalized GNP too, however the NPs were more irregular and rounded. These effects were ascribed to pH variations in the proximity of the functionalized GNP sheets, due to the high density of COOH or NH 2 groups. Because of the different reactivity of anatase {100} and {101} crystalline facets, we hypothesize that the hybrid materials will behave differently as photocatalysts, and that the COOH-GNP-TiO2 hybrids will be better photocatalysts for water splitting and H2 production .

Preparation and application of poly(zwitterionic ionic liquid) to enhance the photocatalytic activity of TiO2

“…5b). A lattice spacing of 0.34 nm could be clearly observed, corresponding to TiO 2 in PIL@TiO 2 [32]. The no-lattice spacing section is attributed to the PIL, which is the amorphous nature [33].…”

Wheat bran valorisation: Towards photocatalytic nanomaterials for benzyl alcohol photo-oxidation

“…Interestingly, the fitting peak at ca. 454.5 eV in the Ti2p spectra of 0.5% Ti-Bran catalyst might be ascribed to the substitution of oxygen by carbon species in the TiO 2 lattice and formation of TieC bond which can also be observed in the C1s spectra from the peak at 282.2 eV (Liu et al, 2014;Sordello et al, 2014). The difference in the fitting peak for Ti2p of 454.5 eV and 458.3 eV is potentially resulted from the presence of CeTieO bond in the TiO 2 lattice that the electronegativity of C (2.55) is lower than that of O (3.44) which results in more electron-rich in TieO bond and further affects the difference in binding energy.…”

V‐N‐C catalysts anchored to mesoporous Al‐SBA‐15 with tailorable pore sizes for the synthesis of spirooxindole dihydroquinazolinones derivatives

“…Meanwhile, two peaks with binding energy at 400.7 eV could be observed in N 1s spectra of the V‐N‐C @Al‐SBA‐15 sample (Figure c). This peak shows binding energy for the amide group (CO–NH‐C) …”