Structure and Photocatalytic Activity of Composites of Semiconducting Nanoparticles in Polymethyl Мethacrylate

Composites made of titanium dioxide (TiO₂), zinc oxide (ZnO) or graphitic carbon nitride (g-C₃N₄) nanoparticles (20–100 nm) in polymethyl methacrylate (PMMA) were fabricated and studied. Nanodispersed powders of these semiconductors were mixed with mechanically grinded PMMA at a weight ratio ranging from 1 : 5 to 1 : 20. The mixture was dissolved in acetone and deposited onto the water surface. Upon solidification and drying in air porous discs as thick as 50–200 μm were formed. They were found to have a mechanical durability at the semiconductor to PMMA ratio above 1 : 20. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction of the samples demonstrated that semiconducting nanoparticles are quasiuniformly distributed in the polymer matrix. Their crystal structure, the particle size, and the composition of the samples do not change as compared to the started powders. Photocatalytic activity of the synthesized composites estimated by decolarization of water solution of the test dye (methylene blue) under UV irradiation was found to be reduced in the sequence TiO₂, g-C₃N₄, ZnO.