Enhanced H2 production activity under solar irradiation over N-doped TiO2 prepared using pyridine as a precursor: a typical sample of N-doped TiO2 series

A series of N-doped TiO2 photocatalysts were synthesized by simple hydrolysis method using titanium isopropoxide and pyridine precusors. XRD studies of all the catalysts showed a single anatase phase and TEM results confirmed that the particles obtained by this procedure are of nano size and in the range of 3–5 nm. UV–vis DRS of N-doped TiO2 catalysts clearly show an enhanced absorption in the visible light region, and the band gaps are seen decreasing as the content of doped nitrogen increases. The formation of oxynitride linkages is evidenced by the FTIR results. Further the XPS analysis confirms the presence of Ti-O-N linkage, and the binding energy values indicate that the doped nitrogen is either interstitial or chemisorbed. The photocatalytic activity of N-doped TiO2 catalysts is evaluated for hydrogen production in methanol: water mixture under solar light irradiation and 0.5 wt% N-doped TiO2 has shown a stable and high activity, 3500 μ mol/h/g.cat. The enhanced hydrogen production activity of N-doped TiO2 catalysts is attributed to the high surface area of the catalysts containing doped nitrogen mostly at the interstitial positions and enhanced visible light absorption.