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Plasmonic photocatalysts have been emerging as a promising candidate for solar energy conversion and environmental remediation. However, those metallic plasmonic photocatalysts inevitably suffer from surface reconstruction and corrosion under harsh reaction conditions, leading to a low activity and poor chemical photostability. Herein, we observe a simultaneous improvement of both activity and photostability on Au/TiO2 nanostructure-based photoanodes induced by an in situ plasmon-mediated electrochemical activation (PMEA) treatment under photoelectrochemical (PEC) water oxidation conditions. Detailed PEC studies demonstrate that the PMEA treatment generates electron-rich surface states at Au/TiO2 interfaces, which results in a high interface charge-transfer efficiency of above 80% and boosts water oxidation activity by 100%. The electron-rich surface states further enhance the PEC stability by reducing the excessive charge accumulation at interfaces and preventing the dissolution of Au. The photoanodes are further tested for the degradation of an antibiotic, ciprofloxacin, which exhibited high PEC activity and stability. Our work provides a convenient method for improving the efficiency and chemical photostability of plasmonic photocatalysts. [ABSTRACT FROM AUTHOR]

University researchers from China, Japan and Canada investigated the kinetics of sulforhodamine-B photooxidation in aqueous media in the presence of Ti02 to determine the type of species and pathways produced in the reaction.

Photodegradation of dyes in the presence of TiO2 particles under air-equilibrated controlled conditions and visible light illumination have been found to induce the generation of hydrogen peroxide (H2O2). H2O2 formed in the process of dye photodegration have been labeled as perfidous intermediate species. It was also observed that the concentration of H2O2 depends on the coverage of the substrates and/or intermediates on the TiO2 surface and the photodegradation rate of the dye.

A study was conducted to analyze the inverse photosensitized oxidative transformation of tetraethylated rhodamine under visible illumination of aqueous titania dispersions. The TiO2 dispersion was prepared by adding TiO2 powder to a solution supporting rhodamine B at specific concentrations. Results indicated that the predomination of deethylation during the initial irradiation period. Findings also showed that increases in anionic surfactants correlated with increases in OH radicals.

Here, we report the fabrication of metastable and stable assembles from tricarbazole-based oligomers via a pathway complex that is achieved by subtly changing the alkyl end chain length. Importantly, compared to stable nanoribbons, the resulting metastable nanoribbons have about a 3-fold enhanced exciton diffusion length that leads to 2- to 4-fold sensitivity enhancement for a broad range of explosives. These results will motivate preparation of kinetically trapped structures with improved properties via pathway complexity, particularly by subtly changing the substituents of molecules. [ABSTRACT FROM AUTHOR]

Examines the titanium oxide (TiO2) photo-assisted degradation of rhodamine B, cationic dye in aqueous dispersions under visible light irradiation. Details on the role of industrial development as a contributing factor to environmental pollution; Information on studies conducted on the photodecomposition of carbon-dioxide; Procedures used to conduct studies on rhodium B.

The article throws light on the hydrogen titanate nanofibers that are covered with anatase nanocrystals. Anatase is regarded as the best photocatalyst for decomposing refractory organic pollutants in water and air. When they are illuminated with ultraviolet (UV) light, anatase particles produce hydroxyl radicals, by which most organic compounds can be degraded completely into carbon dioxide, water, and mineral ions. The photocatalytic reaction takes place on the catalyst surface. Therefore, catalysts of ultrafine anatase powders with a particle size at a scale of tens of nanometers should exhibit a superior activity because of the large specific surface.

Photooxidation of polycyclic aromatic hydrocarbons (PAHs), which are widely observed in atmospheric particulate matter (PM), largely determines their atmospheric fate. In the environment, PAHs are highly complex in chemical composition, and a great variety of PAHs tend to co-occur. Despite extensive investigation on the photochemical behavior of individual PAH molecules, the photochemical interaction among these coexisting PAHs is still not well understood. Here, we show that during photooxidation, there is a strong photochemical synergistic effect among PAHs extracted from soot particles. We find that neither small PAHs with low molecular weights of 200-350 Da and 4-8 aromatic rings (named PAH small ) nor large PAHs with high molecular weights of 350-600 Da and 8-14 aromatic rings (named PAH large ) undergo photooxidation under red-light irradiation (λ = 648 nm), even though PAH large can absorb light with this wavelength. Interestingly, when PAH large is mixed with PAH small , substantial photooxidation is observed for both PAH large and PAH small . Comparisons of in situ infrared (IR), high-resolution mass spectrometry, and electron paramagnetic resonance analysis indicate that the presence of PAH small inhibits the light quenching effect arising from the π-π stacking of PAH large . This leads to the formation of singlet oxygen ( 1 O 2 ), which initiates the photooxidation. Our findings reveal a new mechanism for the photooxidation of PAHs and suggest that complex atmospheric PAHs exhibit distinct photoreactivity from simple systems.