A novel electrosorption-photocatalysis synergistic electrode of TiO(2)/carbon aerogel (TiO(2)/CA) is prepared. The thermal stability and dispersion of the anatase TiO(2) particles are well facilitated by the porous and discontinuous microstructure of CA. The degradation experiments show that the TiO(2)/CA material is not only a good photocatalyst but also an excellent electrosorptive electrode. The TiO(2)/CA is easily molded to an agglomerate electrode. The opaque wastewater with dyestuff is degraded effectively by the electrosorption-promoted photocatalytic process on this electrode. For the simulated methylene blue (MB) wastewater (150 mg L(-1)), the rate constant of MB degradation in the electro-assisted photocatalytic process with the conventional ITO-supported TiO(2) (TiO(2)/ITO) is 0.55 x 10(-3) min(-1) and that the electrosorption-promoted photocatalysis with TiO(2)/CA is 10.27 x 10(-3) min(-1), which is 18 times the former. In the electrosorption-promoted photocatalytic process with TiO(2)/CA, the energy consumption removing per unit TOC is only 15% of that in the electro-assisted photocatalysis with TiO(2)/ITO, because the electrosorption is a nonfaradic process irrelative to any electron transfer and requires very low consumption. This study provides a new method for exploring highly efficient electrosorption-promoted photocatalytics technology in the treatment of opaque wastewater.

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This study presents a stable, efficient visible-light photoelectrocatalytic method induced by molecular-oxygen assistance on a carbon aerogel-supported TiO 2 (TiO 2 /CA) electrode, which combines the in situ surface synthesis of H 2 O 2 and Ti-peroxide photocatalysis under visible light. Results reveal that the optical absorption edge for TiO 2 /CA, which is cathodic polarized under aerobic conditions, is red-shifted to 530 nm. Under visible light (λ > 420 nm) irradiation, the increment from dark current to photocurrent density obtained on TiO 2 /CA is 315 times that on TiO 2 /ITO. The mechanism of the molecularoxygen-induced visible light photoeletrocatalytic activity is proposed and further verified through investigating the hydroxyl radical evolution and monitoring the surface changes of photocatalyst by Raman spectra and diffuse reflection spectra (DRS). This method is further applied in the degradation of the Rhodamine 6G (Rh-6G) wastewater. The result shows that Rh-6G molecules are almost totally decomposed with high TOC removal by the in situ induced photoelectrocatalytic process on TiO 2 /CA (TiO 2 /CA,PE-O 2 ), which is closely related to the degradation mechanism and pathway of the pollutant. It is found that the intermediate products detected in the TiO 2 /CA,PE-O 2 process are less than those in the traditional photocatalytic degradation on TiO 2 /ITO.

A novel TiO(2) nanotube array/CdS nanoparticle/ZnO nanorod (TiO(2) NT/CdS/ZnO NR) photocatalyst was constructed which exhibited a wide-absorption (200-535 nm) response in the UV/Vis region and was applied for the photoelectrocatalytic (PEC) degradation of dye wastewater. This was achieved by chemically assembling CdS into the TiO(2) NTs and then constructing a ZnO NR layer on the TiO(2) NT/CdS surface. Scanning electron microscopy (SEM) results showed that a new structure had been obtained. The TiO(2) NTs looked like many "empty bottles" and the ZnO NR layer served as a big lid. Meanwhile the CdS NPs were encapsulated between them with good protection. After being sensitized by the CdS NPs, the absorption-band edge of the obtained photocatalyst was obviously red-shifted to the visible region, and the band gap was reduced from its original 3.20 eV to 2.32 eV. Photoelectric-property tests indicated that the TiO(2) NT/CdS/ZnO NR material maintained a very high PEC activity in both the ultraviolet (UV) and the visible region. The maximum photoelectric conversion efficiencies of TiO(2) NT/CdS/ZnO NR were 31.8 and 5.98% under UV light (365 nm) and visible light (420-800 nm), respectively. In the PEC oxidation, TiO(2) NT/CdS/ZnO NR exhibited a higher removal ability for methyl orange (MO) and a high stability. The kinetic constants were 1.77×10(-4) s(-1) under UV light, which was almost 5.9 and 2.6 times of those on pure TiO(2) NTs and TiO(2) NT/ZnO NR, and 2.5×10(-4) s(-1) under visible light, 2.4 times those on TiO(2) NT/CdS.

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MOFs (metal-organic frameworks) significantly suffer from water- and heat instable issues, restricting their practical application, such as the capture of hazardous anionic dyes (e.g. Congo red, CR) from water. In present contribution, a series of novel composites (UiO-67@CNTs) composed of microporous UiO-67 (Zr6O4(OH)4(CO2)12) and mesoporous CNTs (carbon nanotubes) have been innovatively synthesized by an in-situ hydrothermal reaction strategy. This UiO-67@CNT impressively retains structural integrity whether contacted with strong acid, distilled water, and strong alkali conditions even for 20 days. Due to existence of CNT, its heat stability can reach up to 480 °C, which is superior to that of UiO-67. Open Zr(IV) sites, mesoporous, and high surface area in the structure of UiO-67@CNTs play associative effects for CR capture ability. CR uptakes over (5.0)UiO-67@CNTs can reach 1,024 mg/g, exceeding some other previous adsorbents in literature. Importantly, UiO-67@CNTs could retain a remarkable CR capture ability even after the fifth cycle. This work expands views for water-heat resistant MOF-based composite with excellent ability of CR capture.

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