Photocatalytic decomposition of methanol-water solution over N-La/TiO2 photocatalysts

Abstract

Manuscript focuses on the role of N-doping on photocatalytic behaviour of N-La/TiO2 materials in decomposition of methanol-water solution. N-La/TiO2 materials were prepared with approximately the same amounts of La (0.14-0.16 wt%) and different amounts of N (0.33-0.97 at. % of surface nitrogen). Addition of small amount of surface nitrogen significantly increased the amount of hydrogen produced for N-La/TiO2 photocatalysts in contrast to TiO2 and La/TiO2. The chemical composition (XRF, AAS, XPS), structural (XRD, Raman, XPS, TEM), textural (N-2-adsorption) and optical properties (DRS) were studied. N-La/TiO2 materials showed approximately the same specific surface area and crystallite size, with values ranging for La/TiO2 and N/TiO2 photocatalysts. For studied N-La/TiO2 photocatalysts, the photocatalytic activity increased with the increasing amount of surface nitrogen (interstitial positions, XPS), and subsequently with increasing amount of oxygen vacancies (Raman spectroscopy) and decreasing amount of surface oxygen species (surface lattice O species and hydroxyl groups evidenced by XPS).