Hierarchical TiO2/CdS "spindle-like" composite with high photodegradation and antibacterial capability under visible light irradiation.

Novel hierarchical TiO(2)/CdS "spindle-like" composites with uniform distribution of CdS nanocrystals on nanoporous TiO(2) mesocrystals were successfully prepared by hydrothermal and hot-injection methods. In this work, the optimal mass ratio of Ti/Cd is determined to be 2 of as-synthesized TiO(2)/CdS composites. This TiO(2)/CdS composite exhibits excellent photocatalytic activity in the degradation of Rhodamine B (RhB) and photocatalytic reaction constant is 10 times higher than that of TiO(2), 3.5 times higher than that of CdS and higher than other TiO(2)/CdS composites with different amount of Ti/Cd mass ratio. In addition, TiO(2)/CdS with optimal amount of CdS kills 99.9% of Escherichia coli in 10 min under visible-light irradiation, which shows significant higher efficiency than pure TiO(2), CdS and other TiO(2)/CdS composites. The excellent performances of this hierarchical composite are ascribed to its outstanding properties, including large specific surface area (BET), high crystallinity of oriented single-crystal-like nanoporous TiO(2) mesocrystals for charge transfer, retarded recombination of photogenerated electron-hole pairs via isolating electrons and holes in two different materials, and extended photo response of this hierarchical composite to the visible region. Considering all these superior properties and abilities, this hierarchical TiO(2)/CdS "spindle-like" composite will show great potential for applications in the water purification field.

Gao P ，Liu J ，Zhang T ，Sun DD ，Ng W ... -  《-》

Graphene oxide-CdS composite with high photocatalytic degradation and disinfection activities under visible light irradiation.

Graphene oxide (GO)-CdS composites were synthesized via a novel two-phase mixing method successfully. CdS nanoparticles were uniformly self-assembled on GO sheets at water/toluene interface. The photocatalytic degradation (photodegradation) and disinfection activities of GO-CdS composites were investigated thoroughly. The results show that GO-CdS composites exhibit higher efficiency in photodegradation of various water pollutants than pure CdS nanoparticles under visible light irradiation. In addition, the interactions between GO sheets and CdS nanoparticles inhibit the photo-corrosion of CdS and leaching of Cd(2+). Only 3.5 wt% Cd(2+) of GO-CdS was leached out after photodegradation, while 38.6 wt% Cd(2+) of CdS was lost into aqueous solution. Furthermore, the disinfection activity of GO-CdS composites was investigated for the first time. Nearly 100% of both Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) were killed within 25 min under visible light irradiation. The excellent performances of GO-CdS composites can be attributed to that (1) effective charge transfer from CdS to GO reduces the recombination rate of photo-generated electron-hole pairs; (2) uniform deposition of CdS on GO sheets eliminates aggregation of CdS nanoparticles; and (3) the strong interactions between GO and CdS enhancing the durability of GO-CdS composites. Finally, the mechanism behind these excellent performances was verified by transient photocurrent measurement and further confirmed by ESR technique as well as employing a radical scavenging species - dimethyl sulfoxide (DMSO).

Gao P ，Liu J ，Sun DD ，Ng W ... -  《-》

Synthesis of one-dimensional CdS@TiO₂ core-shell nanocomposites photocatalyst for selective redox: the dual role of TiO₂ shell.

Liu S ，Zhang N ，Tang ZR ，Xu YJ ... -  《-》

Photodecolorization of Rhodamine B on tungsten-doped TiO2/activated carbon under visible-light irradiation.

Tungsten-doped TiO(2)/activated carbon catalysts have been prepared by a supercritical-pretreatment-assisted sol-gel process. The structural features of the photocatalysts have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV/Vis diffuse-reflectance spectroscopy (DRS), electron dispersive X-ray (EDX), photoluminescence spectroscopy, and Brunauer-Emmett-Teller (BET) analysis. The results revealed that a W-TiO(2) layer was coated on the AC surface, and had higher surface area and smaller crystallite size than TiO(2)/AC obtained by a similar route. The W dopant was responsible for narrowing the band gap of TiO(2) and shifting its optical response from the ultraviolet (UV) to the visible-light region. The photocatalytic performances of the supported catalysts have been evaluated for the degradation of Rhodamine B (RhB) solution under visible-light irradiation. Compared with bulk W-TiO(2), the photoactivity was obviously enhanced when it was coated onto AC. In addition, it was found that the reactivity showed a significant relationship with the amount of W dopant, and the photoactivity order of the catalysts from weak to strong showed good agreement with their PL intensities. The effects of TiO(2) content, tungsten ion content, catalyst amount, pH, and initial RhB concentration have been examined as operational parameters. The photocatalytic reactions followed pseudo-first-order kinetics and are discussed in terms of the Langmuir-Hinshelwood model.

Li Y ，Zhou X ，Chen W ，Li L ，Zen M ，Qin S ，Sun S ... -  《-》

Mesoporous silica nanospheres decorated with CdS nanocrystals for enhanced photocatalytic and excellent antibacterial activities.

Hu JL ，Yang QH ，Lin H ，Ye YP ，He Q ，Zhang JN ，Qian HS ... -  《-》