Synthesis and photoelectrochemical studies of N, Zr co-doped mesoporous titanium dioxide

• Synthesis of novel N, Zr co-doped mesoporous TiO2 with controlled composition.
• Band gaps of the N, Zr co-doped TiO2 are between 2.71 and 2.76 eV.
• The co-doped Zr level strongly affect the catalytic activity of the mesoporous TiO2.
• The N, Zr co-doped TiO2 with 1.0% Zr exhibited the highest photocatalytic activity.

Here we report on the synthesis of novel N, Zr co-doped mesoporous TiO2 photocatalysts via a facile solution combustion method. The properties of the nanoparticles were characterized by transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–Visible reflectance diffuse spectroscopy. Electrochemical methods such as linear sweep voltammetry (LV), chronoamperometry (CA), and impedance spectroscopy were employed to measure the photoelectrochemical properties of the samples. Our experimental results have shown that an appropriate level of Zr doping into the N-mono doped TiO2 served to increase both the BET surface areas as well as their photocatalytic activities. The band gaps of the as-synthesized N, Zr co-doped TiO2 were between 2.71 and 2.76 eV, which proved experimentally that the band gap of TiO2 could be narrowed through N and Zr co-doping. The effect of the co-doped Zr level has been systemically investigated, showing that the synthesized N, Zr co-doped mesoporous TiO2 with 1.0% Zr exhibited the highest photocatalytic activity under the simulated sunlight and visible light irradiation. The high stability of the photocatalysts was also confirmed.