Boron and nitrogen co-doped titania with enhanced visible-light photocatalytic activity for hydrogen evolution

A visible-light boron and nitrogen co-doped titania (B-N-TiO2) photocatalyst was prepared by sol-gel method with titanium tetra-n-butyl oxide, urea and boric acid as precursors. The photocatalyst was characterized by Fourier Transform Infrared (FT-IR), UV-vis diffusive reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), BET and electrochemistry method. Photocatalytic activity for hydrogen production over platinized B-N-TiO2 under visible-light (λ ≥ 420 nm) irradiation was investigated. In nitrogen doped titania (N-TiO2) NTiO bond is formed, which extends the absorption edge to the visible-light region. A part of doping boron enters into titania lattice and most of the boron exists at the surface of the catalyst. The crystallite size of B-N-TiO2 decreases compared to N-TiO2, while its photocurrent and the surface hydroxyl group increase. Furthermore, doping boron could act as shallow traps for photoinduced electrons to prolong the life of the electrons and holes. Therefore, the visible-light activity of B-N-iO2 increases greatly compared with that of N-TiO2.