Fabrication of Yb-doped TiO₂ using liquid phase plasma process and its photocatalytic degradation activity of naproxen

Photocatalysts responding to visible light were prepared by doping ytterbium (Yb) to TiO₂ powder by LPP method. Yb₂O₃ nanoparticles were uniformly precipitated on the surface of TiO₂ powder, and when the precursor concentration was increased, the precipitated Yb₂O₃ nanoparticles increased. The precipitated Yb element lowered the band gap energy of Yb-doped TiO₂ photocatalyst (YTP) by 0.07 to 0.14 eV compared to bare TiO₂. YTPs degraded naproxen (NPX) better than bare TiO₂, especially under blue LED light (maximum wavelength 470 nm), and YTP containing higher Yb elements showed higher decomposition activity. NPX was decomposed into CO₂ and H₂O by decarboxylation and demethylation by hydroxyl radicals generated from TiO₂ photocatalysts, suggesting a degradation pathway based on the three intermediates detected by LC/MS analysis.