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A series of novel metal W connected Z-scheme C fibers@WO 3-x (0 ≤ x < 3) core-shell composites were developed by simply pyrolyzing preoxidized polyacrylonitrile fibers impregnated with slurries of WO 3 nanopowder in absolute ethanol in a vacuum furnace. Such structured composites are a kind of more excellent solar-driven photocatalyst for degrading various aqueous organic and inorganic environmental pollutants, compared with pure tungsten oxides catalysts under the same condition. The optimally selected composite catalyst (x = 2.01) was also applied in photocatalytically purifying waste water from paper mills under sunlight, presenting high efficiency in reducing chemical oxygen demand, biology oxygen demand and heavy metal Cr content, displaying great prospect in environmental remediation through removing various toxic industrial chemicals. The greatly enhanced photocatalytic performance could be mainly ascribed to the C fiber core and metal W connection layer between the tungsten oxides and C core in the composites, which can promptly conduct electrons and promote the separation of photogenerated electrons and holes. Moreover, this work provides a simple, eco-friendly and very efficient synthesis approach, which will be of much help to design diversified semiconductors composite structures, and suitable for large-scale production and thus practical industrial application. [ABSTRACT FROM AUTHOR]

A series of direct Z-scheme FeIn 2 S 4 /Bi 2 WO 6 hierarchical heterostructures with intimate interface contacts were synthesized by in-situ growth route and characterized by systematical analyses. All as-prepared FeIn 2 S 4 /Bi 2 WO 6 nanocomposites showed significantly enhanced photocatalytic activity towards photodegradation for the removal of tetracycline hydrochloride (TCH) in comparison with individual FeIn 2 S 4 and Bi 2 WO 6. Meanwhile, the highest photocatalytic degradation activity can be achieved by modulating adding amount of FeIn 2 S 4 in FeIn 2 S 4 /Bi 2 WO 6 nanocomposites and the optimized component ratio of FeIn 2 S 4 to Bi 2 WO 6 is determined to be 10 wt%. The enhanced photocatalytic activity could be ascribed to efficient separation between photogenerated holes and electrons based on the construction of direct Z-scheme system. The high photocatalytic stability of resultant 10 wt% FeIn 2 S 4 /Bi 2 WO 6 nanocomposites was revealed through six successive recycling reactions. The main intermediate generated during TCH photodegradation was explored by HPLC-MS. Besides, the direct Z-scheme photocatalytic mechanism was confirmed by band position analysis, electron spin resonance (ESR) and active species capture experiment. [ABSTRACT FROM AUTHOR]

Novel ZnO/ZnFe 2 O 4 /Ag hollow one-dimensional multicomponent heterojunctions with different ZnO/ZnFe 2 O 4 ratios were successfully obtained via a simple electrospinning method. These multicomponent heterojunctions exhibited a largely enhanced photocatalytic performance for various reactions compared with pure ZnFe 2 O 4 without heterojunctions, ZnO/ZnFe 2 O 4 and ZnFe 2 O 4 /Ag with single heterojunctions. The enhancement can be mainly ascribed to the synergism of multicomponent heterojunctions, which can significantly improve the optical absorption abilities, prompt the separation of photogenerated carriers, and depress the recombination of electron-hole pairs. Hence, the simultaneous and efficient generation of electrons and holes with strong reduction and oxidation abilities, respectively, can lead to effective reaction with the target degradants. In addition, the unique hollow nanofiber structure can also prompt the activities by decreasing the distance for charge carrier transfer to the solution during the photocatalytic process. Additionally, the influence of the number of heterojunctions on the photoactivity was also discussed via varying the ZnO loading amount. This work displays an ingenious design to elevate photocatalytic performances of spinel ZnFe 2 O 4 for solving its biggest problems in the photocatalytic applications, and reveals the rational design of photocatalysts for efficient water pollutants removal. [ABSTRACT FROM AUTHOR]