Electron-hole recombination is one of the major factors limiting the efficiency of ZnO-based photocatalysts. In this work, a 2-fold enhancement strategy was employed to suppress electron-hole recombination and boost photocatalytic efficiency. First, significantly enhanced photocatalytic activity of ZnO by introducing graphene oxide (GO) was systematically investigated. Hybrid photocatalysts with different weight ratios of ZnO to GO (from 0.95:0.05 to 0.70:0.30) were synthesized and characterized. The results indicated that when the proportion ratio of ZnO to GO reached 0.85:0.15, the as-synthesized ZnO-GO nanocomposite exhibited the maximum photocatalytic efficiency on methylene blue with an apparent rate constant κapp almost 10 times faster than that of pure ZnO under UV illumination. GO was suggested to enhance the photocatalytic activity of ZnO because of its great capability in dye adsorption and charge separation. Second, Pd nanoparticles were introduced to decorate ZnO-GO to produce generally better photocatalyst ZnO-GO-Pd nanocomposites. The junction between Pd and ZnO was believed to also effectively separate the photogenerated charges due to the metal-semiconductor diode effect. These two systems of ZnO-GO and ZnO-GO-Pd nanocomposites are expected to have a broad range of applications in environmental conservation.
The efficient cutaneous wound healing accompanied with the enhanced skin appendage regeneration is still a challenge. The bacterial infection and excessive/prolonged inflammation inhibit wound healing process and result in the scar formation. Herein, we reported an anti-inflammatory polycitrate-polyethyleneimine-Ibuprofen (PCEI) and multifunctional PCEI-based F127-ε-polypeptide-alginic (FEA) dressing (FEA-PCEI) for accelerating wound healing and hair follicle neogenesis. PCEI showed the excellent anti-inflammation function through stimulating macrophage towards anti-inflammatory M2 subtype polarization. The FEA-PCEI dressing showed the temperature-response gelation, injectability, robust antibacterial activity, light-damage-resistant, homeostasis ability, and good cytocompatibility. The optimized dosage of FEA-PCEI dressing could significantly accelerate wound healing with anti-infection ability, reduce the scar formation, and promote the hair follicle neogenesis. This study provided a wound-repairing strategy through regulating the phenotype of immune cells by the designing bioactive multifunctional biomaterials.
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