Bifunctionalization of carbon nitride by incorporation of thiophene ring and polar nickel complex to promote photocatalytic activity for hydrogen evolution.

Photocatalytic performance of polymeric carbon nitride (CN) is primarily restricted by limited light utilization and poor charge separation efficiency. To this end, skeleton modification strategy was adopted by attaching thiophene ring and polar nickel complex (NiL) onto CN. The obtained bifunctionalized carbon nitride (TCN-NiL) displayed obviously elevated optical absorption and photoexcited charge separation efficiency. The NiL, with polar structure, plays as active sites like cocatalyst thus exhibited platinum-like H2 evolution activity from water splitting under visible light. The optimized photocatalytic H2 generation rate over TCN-NiL reached 136.7 µmol·h-1 without any cocatalyst, the highest rate reported so far in noble-metal-free CN-based catalysts, which is 5 times of that of CN loaded with 3 wt% Pt. Additionally, the maximum wavelength of performing H2 production capacity over TCN-NiL extends to 550 nm from 450 nm of CN, suggesting an excellent visible light absorption ability. This work provides a way for modifying CN to enhance the photocatalytic activities in a noble metal free system.

Inlay of Bi2O2CO3 nanoparticles onto Bi2WO6 nanosheets to build heterostructured photocatalysts.

Surface-dispersive-type Bi2O2CO3/Bi2WO6 heterostructured nanosheets were successfully prepared via anion exchange in a hydrothermal process with the graphitic carbon nitride (g-C3N4) as a precursor of CO3(2-). The Bi2O2CO3 nanoparticles (with diameters about 5 nm) were highly homogeneously dispersed and inlaid in the single-crystalline Bi2WO6 nanosheets. The composites with intimate interfacial contacts between Bi2O2CO3 and Bi2WO6 exhibited superior visible light photocatalytic activity towards the degradation of rhodamine B (RhB). The composite nanosheets containing 7.86 wt% Bi2O2CO3 showed the best performance and the degradation rate of RhB was 6 times faster than that with the bare Bi2WO6. The dramatic enhancement of the photocatalytic activity of the Bi2O2CO3/Bi2WO6 photocatalysts can be attributed to the hetero-interfaces between Bi2O2CO3 and Bi2WO6, their intrinsically layered structure, two-dimensional morphology and the effective separation of the photoinduced carriers at the interfaces and in the semiconductors. This method can be used to design and prepare other Aurivillius heterostructured semiconductors for efficient light harvesting and energy conversion applications.

Wide bandgap Bi2O2CO3-coupled Bi2MoO6 heterostructured hollow microspheres: one-pot synthesis and enhanced visible-light photocatalytic activity.

Hierarchical Bi2O2CO3/Bi2MoO6 heterostructured photocatalysts composed of nanoplatelets of Bi2O2CO3 and Bi2MoO6 were successfully prepared by a facile template-free solvothermal process. The microsphere-like Bi2O2CO3/Bi2MoO6 composites exhibited superior visible light photocatalytic activity towards degradation of rhodamine B. The highest degradation efficiency was observed on the material with the Bi/Mo molar ratio of 2.88/1, which can degrade 99% rhodamine B within 90 min, while only 44% rhodamine B was degraded over the pure Bi2MoO6 microspheres and 2% over the Bi2O2CO3 nanoplatelets. The dramatic enhancement in their photocatalytic performance of the Bi2O2CO3/Bi2MoO6 photocatalysts can be attributed to the high surface area and the effective separation of the photoinduced carriers at the interfaces and in the semiconductors. The photo-generated h+(VB) in the Bi2O2CO3/Bi2MoO6 photocatalysts turn out to be the dominant active species in the photocatalytic reaction. Importantly, Bi2O2CO3/Bi2MoO6 displayed visible-light photocatalytic activity for the destruction of E. coli (the percent kill is 99.09 in 60 min). In addition, the Bi2O2CO3/Bi2MoO6 composite was very stable during the reaction and can be used repeatedly. These features mean the present heterostructured photocatalyst can be applied in environmental remediation, and waste water disinfection.

Preparation and antibacterial property of waterborne polyurethane/Zn-Al layered double hydroxides/ZnO nanocomposites.

In this work, a novel environmental-friendly waterborne polyurethane/ZnAl-layered double hydroxides/ZnO nanoparticles composite (WPU/ZnAl-LDHs/ZnO) was synthesized via in-situ polymerization. ZnAl-LDHs and ZnAl-LDHs/ZnO were synthesized by refluxing in an oil bath. In order to disperse ZnAl-LDHs/ZnO homogeneously into WPU matrix, ZnAl-LDHs/ZnO was firstly functionalized by isophorone diisocyanate. The incorporated content of ZnAl-LDHs/ZnO in the composite has profound effect on such physical properties as mechanical strength, thermal stability and water swelling. It is demonstrated that appropriate amount of ZnAl-LDHs/ZnO with good dispersion in the WPU matrix significantly improves the physical performance of the composites. Finally, the antibacterial activity of the composite was tested against G(-) Escherichia coli and G(+) Staphylococcus aureus. The results indicate that WPU incorporated with ZnAl-LDHs/ZnO shows strong antibacterial activity upon contact.

Monodispersed Ag3PO4 nanocrystals loaded on the surface of spherical Bi2MoO6 with enhanced photocatalytic performance.

Spherical Bi(2)MoO(6) nanoarchitectures with scale of 500 nm-2 µm were prepared by a solvothermal reaction using bismuth nitrate and ammonium molybdate as precursors. Ag(3)PO(4) nanoparticles were then deposited onto the surface of Bi(2)MoO(6)via a facile deposition-precipitation technique. The photocatalytic tests display that the Ag(3)PO(4)/Bi(2)MoO(6) nanocomposites possess a much higher rate for degradation of rhodamine B and methylene blue than the pure Ag(3)PO(4) nanoparticles and Bi(2)MoO(6) under visible light. The catalytic activity of the composite photocatalysts is greatly influenced by the loading level of Ag(3)PO(4). The 50 mol% Ag(3)PO(4)-loaded Bi(2)MoO(6) spheres exhibit the highest photocatalytic activity in both the decolorization of RhB and MB. The observed improvement in photocatalytic activity is associated with the extended absorption in the visible light region resulting from the Ag(3)PO(4) nanoparticles, and the effective separation of photogenerated carriers at the Ag(3)PO(4)/Bi(2)MoO(6) interfaces. In addition, the composite can be easily reclaimed by sedimentation without any loss of its stability. Moreover, the tests of radical scavengers confirmed that h(+) and ˙OH were the main reactive species for the degradation of RhB.