Polythiophene as a Double-Electrostatic Template for Zinc Oxide and Gold: Multicomponent Nano-Objects for Enhanced Photocatalysis

Using electrostatic self-assembly and electrostatic nanotemplating,a quaternary nanostructured system consisting of zinc oxide nanoparticles,gold nanoparticles, poly[3-(potassium-4-butanoate)thiophene-2,5-diyl](PT), and methyltrioctylammonium chloride (MTOA) (PT-MTOA-ZnO-Au)was designed for aqueous photocatalysis. The PT-MTOA hollowsphere aggregates served as an electrostatic template for both individualinorganic nanoparticles controlling their morphology, stabilizingthe nanoparticles, and acting as a photosensitizer. The hybrid structuresincluded spherical ZnO nanoparticles with a diameter of d = 2.6 nm and spherical Au nanoparticles with d =6.0 nm embedded in PT-MTOA hollow spheres with a hydrodynamicradius of R (H) = 100 nm. The ZnO nanoparticlesacted as the main catalyst, while the Au nanoparticles acted as thecocatalyst. As a photocatalytic model reaction, the dye degradationof methylene blue in aqueous solution using the full spectral rangefrom UV to visible light was tested. The photocatalytic activity wasoptimized by varying the Zn and Au loading ratios and was substantiallyenhanced regarding the components; for example, it was increased byabout 61% using PT-MTOA-ZnO-Au compared to thecomposite without gold particles. A photocatalytic mechanism of themethylene blue degradation was proposed when catalyzed by these multicomponentnano-objects. Thus, a simple procedure of templating two differentnanoparticle species within the same cocatalytically active templatehas been demonstrated, which can be extended to other inorganic particles,making a variety of task-specific catalysts accessible.

Automated summary

Using electrostatic self-assembly and nanotemplating, a quaternary nanostructured system (PT-MTOA-ZnO-Au) consisting of zinc oxide and gold nanoparticles in poly[3-(potassium-4-butanoate)thiophene-2,5-diyl] and methyltrioctylammonium chloride was designed for aqueous photocatalysis. The hollow spheres of PT-MTOA served as an electrostatic template, controlling the morphology and stabilizing the nanoparticles. The photocatalytic activity was enhanced by incorporating gold nanoparticles into the system.