All-weather-available electrothermal and solarthermal wood-derived porous carbon-based steam generators for highly efficient water purification

Solar steam generation devices cannot work properly under weak solar light irradiation and even no solar light. Herein, an all-weather-available electrothermal and solarthermal wood-derived porous carbon-based water steam generation device...

Au/CeO2 Photocatalyst for the Selective Oxidation of Aromatic Alcohols in Water under UV, Visible and Solar Irradiation

Au nanoparticles supported on CeO2 have been prepared and investigated as photocatalysts for the photocatalytic selective oxidation of benzyl alcohol and 4-methoxybenzyl alcohol to the correspondent benzaldehydes, in aqueous suspensions and room conditions under UV, visible and natural solar light irradiation. Au nanoparticles have been supported by impregnation (1 and 3 wt.%) on two types of CeO2 (i.e., a commercial one and a home prepared oxide obtained in the presence of NaOH as precipitation agent). The Au impregnated samples showed strong visible radiation absorption at 565–570 nm associated to localized surface plasmon resonance (LSPR). The bare CeO2 samples are activated by UV light and resulted virtually inactive under visible irradiation, whereas the presence of Au improved both the conversion of the alcohols and the selectivity of the reaction towards the aldehyde, giving rise to good results, particularly under visible and natural solar light irradiation. The activity of the materials increased by increasing the Au content.

Influence of rGO and Preparation Method on the Physicochemical and Photocatalytic Properties of TiO2/Reduced GraPhene Oxide Photocatalysts

In this study, a series of TiO2/rGO photocatalysts were obtained with a two-step procedure: a solvothermal method and calcination at 300–900 °C in an argon atmosphere. It was noted that the presence of rGO in photocatalysts had an important role in the changes in crystallite size and specific surface area. In TiO2/rGO samples, different surface functional groups, such as C−Cgraph, C−Caliph, C−OH, C=O, and CO(O), were found. It was observed that rGO modification suppressed the anatase-to-rutile phase transformation. The photocatalytic activity of the obtained nanomaterials was investigated through the decomposition of methylene blue under UV and artificial solar light irradiation. It was found that the adsorption degree played an important role in methylene blue decomposition. The experimental results revealed that TiO2/rGO samples exhibited superior removal efficiency after calcination for methylene blue compared toTiO2 without rGO, as well as a commercial photocatalyst KRONOClean 7000. It was noted that photocatalytic activity increased with the increase in the calcination temperature. The highest activity was observed for the sample calcined at 700 °C, which consisted of 76% anatase and 24% rutile. This study clearly demonstrated that TiO2/rGO samples calcined in argon can be used as efficient photocatalysts for the application of methylene blue decomposition.

Facile synthesis of ZnO/CuO/Ag2O ternary metal oxide nanocomposite for effective photodegradation of organic water pollutants

The current study is focused on fabrication of a ternary metal oxide nanocomposite (ZnO/CuO/Ag2O) as an efficient and superior photocatalyst by step wise implanting of p-type of CuO and Ag2O semiconductors onto n-type of semiconductor (ZnO) via chemical method. The structural and textural characteristics of manufactured samples were characterized by X-ray diffraction (XRD), Fourier Transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy combine electron dispersive spectroscopy (FESEM-EDS) and UV-vis spectroscopy. The photocatalytic performance of the fabricated ternary nanocomposite was tested against the photocatalytic degradation of Crystal violet (CV) and Rhodamine B (RhB) organic dyes under solar light irradiation. The ternary nanocomposite demonstrated about 99.05% and 97.38% degradation efficiencies for CV and RhB dyes under solar light irradiation in a time period of 105 min. The calculated rate constants (k, min−1) for degradation under solar light over the ZnO/CuO/Ag2O nanocomposite were 4.26 and 3.61 times higher than the k value obtained over ZnO nanoparticles for CV and RhB dyes, respectively. The main reactive species taken part in the photodegradation processes were •OH and •O2− over ZnO/CuO/Ag2O photocatalyst under solar light illumination. Further the recycle experiments confirm good reusability and photo-stability of ZnO/CuO/Ag2O ternary nanocomposite.