Surface plasmon resonance excited electron induction greatly extends H2 evolution and pollutant degradation activity of g-C3N4 under visible light irradiation

Energy crises and environmental pollution have sparked tremendous research work to handle their impacts. Herein, we fabricated Au/g-C₃N₄ nanocomposites to produce H₂ and degrade 2,4-dichlorophenol (2,4-DCP) under visible light and at different wavelengths. Interestingly, the optimized photocatalyst generated 114 μmol H₂ and degraded 25% 2,4-DCP in 1 hr as compared with 10 μmol H₂ generation and 8% 2,4-DCP degradation by pure g-C₃N₄. This improvement is credited to the extended light absorption and improved charge induction from gold to g-C₃N₄ even at 590 nm as confirmed from photoluminescence, surface photovoltage, and photoelectrochemical study of the samples. Moreover, the surface catalytic property of g-C₃N₄ was much improved after loading a proper amount of gold nanoparticles. We hope that this technique to photosensitize semiconductors with noble metal nanoparticles may provide a feasible way to construct surface plasmon resonance-assisted photocatalysts to cope with energy crises and environmental pollution simultaneously.     

Visible light-excited surface plasmon resonance charge transfer significantly improves the photocatalytic activities of ZnO semiconductor for pollutants degradation

To effectively address environmental pollution, we synthesized Au-loaded ZnO nanocomposites and applied for the photocatalytic degradation of 2-chlorophenol (2-CP) under visible light irradiation. The as-prepared nanophotocatalysts delivered much improved photocatalytic degradation activities as compared to the bare ZnO nanoparticles and 32% of the pollutant was degraded with 2AuZnO in 1 hr. These improved photoactivities are attributed to the extended visible light absorption due to the surface plasmon resonance property of the loaded Au nanoparticles. Moreover, Au nanoparticles played important role in charge separation by inducting excited electrons to the conduction band of ZnO photocatalyst and surface catalysis as confirmed from photoluminescence spectra and amount of the generated hydroxyl radicals. The trapping experiments confirmed that positive holes were the major degrading species during the photocatalytic degradation of 2-CP. This work provides a feasible way to improve the photocatalysis by introducing a proper amount of noble metals over the surface of semiconductor photocatalysts.     

Microfluidic formation of pH responsive 5CB droplets decorated with PAA-b-LCP

We are reporting for the first time the pH responsiveness of liquid crystal (LC) microdroplets decorated with an amphiphilic block copolymer of PAA-b-LCP. We successfully demonstrated the adsorption of block copolymer on LC droplets by fluorescence microscopy and pH response to the radial-to-bipolar orientational change of the LC droplets by changing pH from 12 to 2 through the polarized optical microscope (POM). We believe that our results may pave the way for the generation of monodisperse droplets decorated by various amphiphilic block copolymers which respond to several kinds of the external stimuli. These developments may be important for potential applications of the LC droplets in sensing and encapsulation fields.