Adsorption and photo-oxidation of 3,4-dihydroxy-cinnamic acid on TiO2 films

The photo-oxidation of 3,4-dihydroxy-cinnamic acid (DHCA) is investigated on TiO2 films prepared from commercial Degussa P-25 (FP25 films) and from colloidal TiO2 prepared by the sol-gel method (FSG films). Photo-oxidation rates have been found to be inversely correlated to the amount of adsorbed species. The extent of adsorption increases as the solution pH increases from 1 to 4 and is more pronounced in the case of FP25 samples for which the amount of adsorbed species is 2.7 x 10-10 mol cm-2 i.e. about threefold higher than for the FSG case. Analysis of DHCA adsorption on TiO2 suspensions provided information complementary to that collected on films. Diffuse reflectance UV-visible and FTIR spectra of adsorbed DHCA are conspicuously different for the two types of films

Selective Photooxidation and Photoreduction Processes at Surface-Modified by Grafted Vanadyl

Titanium dioxide was surface-modified by grafting vanadyl species using vanadyl triisopropoxide as a precursor. The resulting material, (VOx)n/TiO2, was characterized by Raman spectroscopy and photoelectrochemical methods. Photocatalytic oxidation of benzyl alcohol and cyclohexene were used to test oxidation selectivity and 4-nitro-benzaldehyde to assess selective photoreduction. The surface-modified TiO2exhibits an enhanced selectivity to benzaldehyde in the photocatalytic oxidation of benzyl alcohol in an aqueous medium and an increase of cyclohexenol formation in the case of cyclohexene in nonaqueous solvent. The salient result is the 100% selective reduction of the nitrogroup in 4-nitro-benzaldehyde achieved under mild experimental conditions

Preparation, Characterisation, and Photocatalytic Behaviour of Co-TiO2 with Visible Light Response

The preparation of cobalt-modifiedTiO2(Co-TiO2) was carried out by the incipient impregnation method starting from commercialTiO2(Degussa, P-25) and cobalt acetate. XPS data show that cobalt is incorporated as divalent ion, and it is likely present within few subsurface layers. No appreciable change in structural-morphologic properties, such as surface area and anatase/rutile phase ratio, was observed. Conversely, Co addition brings about conspicuous changes in the point of zero charge and in surface polarity. Diffuse reflectance spectra feature a red shift in light absorption that is dependent on the amount of cobalt. The influence of cobalt addition on the performance ofTiO2as a photocatalyst in the degradation of 4-chlorophenol and Bisphenol A is investigated. The results show that the modified oxide presents a higher photoactivity both for illumination with UV-visible (λ>360 nm) and visible light (λ>420 nm;λ>450 nm), and that this enhancement depends on the amount of the added species and on the final thermal treatment in the preparation step. We also show that Co-TiO2is a more active catalyst than pureTiO2for the reduction ofO2in the dark, which is an important reaction in the overall photocatalytic processes

The acetyltransferase p300 is recruited in trans to multiple enhancer sites by lncSmad7

The histone acetyltransferase p300 (also known as KAT3B) is a general transcriptional coactivator that introduces the H3K27ac mark on enhancers triggering their activation and gene transcription. Genome-wide screenings demonstrated that a large fraction of long non-coding RNAs (lncRNAs) plays a role in cellular processes and organ development although the underlying molecular mechanisms remain largely unclear (1,2). We found 122 lncRNAs that interacts directly with p300. In depth analysis of one of these, lncSmad7, is required to maintain ESC self-renewal and it interacts to the C-terminal domain of p300. lncSmad7 also contains predicted RNA-DNA Hoogsteen forming base pairing. Combined Chromatin Isolation by RNA precipitation followed by sequencing (ChIRP-seq) together with CRISPR/Cas9 mutagenesis of the target sites demonstrate that lncSmad7 binds and recruits p300 to enhancers in trans, to trigger enhancer acetylation and transcriptional activation of its target genes. Thus, these results unveil a new mechanism by which p300 is recruited to the genome

Sistemi fotocatalitici per l'ossigenzaione di substrati organici

P.R.I.N. 2004. Titolo del programma di ricerca: attivazione ossidativa di molecole organiche attraverso nuovi processi catalitici e fotocatalitici. Coordinatore nazionale Prof. A. Albin

Fotocatalisi ossidativa con sistemi inorganici organizzati

Progetto FAR 2006 (ex 60%). Il progetto prevede l'impiego di metodi fotochimici per attivare sistemi inorganici organizzati in grado di catalizzare la funzionalizzazione di substrati organici di interesse in sintesi applicata. I sistemi che sono oggetto di studio sono: anione decatungstato supportato su resina a scambio anionico, FeCl3 su resina anionica e TiO2 mesoporoso. Gli intermedi di interesse sono: epossidi (da alcheni) ottenuti attraverso la formazione di bromoidrine (utilizzando ione bromuro come co-catalizzatore), alcani alogenati alcoli e chetoni (da idrocarburi

A photo-(electro)-catalytic system illustrating the effect of lithium ions on titania surface energetics and charge transfer

We describe the effect of Li+ on photoinduced charge transfer at TiO2 in acetonitrile solutions at open circuit (photocatalytic conditions) or under potential control. Using 2-propanol and 4-nitrobenzaldehyde as probe scavengers of holes and electrons, respectively, we aim to demonstrate the importance of tuning the chemical role of electrons and holes through control of surface and interface properties