0000000000292064
AUTHOR
Shigeru Ikeda
Photocatalytic degradation of organic compounds in aqueous systems by transition metal doped polycrystalline TiO2
Abstract Some probe catalytic photooxidation reactions with aliphatic and aromatic organic compounds having different acid strengths, i.e. methanoic acid, ethanoic acid, benzoic acid and 4-nitrophenol, were carried out in aqueous systems by using polycrystalline TiO2 powders doped with various transition metal ions (Co, Cr, Cu, Fe, Mo, V and W). The Co-doped powder showed to be more photoactive than the bare TiO2 for methanoic acid degradation while the behaviour of TiO2/Cu and TiO2/Fe was similar to that of the support. TiO2/W was the most efficient sample for the photodegradation of benzoic acid and 4-nitrophenol, TiO2 the most active powder for ethanoic acid. A tentative explanation is p…
Photocatalytic activity of transition-metal-loaded titanium(IV) oxide powders suspended in aqueous solutions: Correlation with electron–hole recombination kinetics
Photocatalytic reactions by transition-metal (V, Cr, Fe, Co, Cu, Mo, or W) loaded TiO2 (M-TiO2) powders suspended in aqueous solutions of methanol, (S)-lysine (Lys), or acetic acid were investigated. The photoactivities of various samples were compared with the rate constant (kr) of recombination of photoexcited electrons and positive holes determined by femtosecond pump–probe diffuse reflection spectroscopy (PP-DRS). As a general trend, increased loading decreased the rate of formation of the main products (H2 , pipecolinic acid (PCA), and CO2) under UV (>300 nm) irradiation, and the effect became more intense on increasing the loading. In PP-DRS, these M-TiO2 gave similar decays of absorp…