Nitrogen doping on the core-shell structured Au@TiO2 nanoparticles and its enhanced photocatalytic hydrogen evolution under visible light irradiation

The current study concerns about the large band gap of TiO2 for its use as photocatalysts. The photocatalytic activity of core-shell structured Au@TiO2 nanoparticles were enhanced by the doping of nitrogen. The nitrogen doping has been done by simple hydrothermal method taking ethylenediamine as the precursor for nitrogen. The crystals structure of TiO2 shell remained unaltered even with the introduction of nitrogen. The photocatalytic activity of the prepared samples were evaluated towards the hydrogen evolution from photocatalytic water splitting under solar light irradiation. It was found that nitrogen doped core-shell structured Au@TiO2 nanoparticles (Au@N-TiO2) showed higher photocatalytic activity with an average H2 evolution rate of 4880 μmol h−1g−1, which is 3.79 times more than that of bare TiO2 in 4 h under xenon light irradiation. The relationship among the other samples was in order of Au@N-TiO2 > Au@TiO2 > N-TiO2 > TiO2. This enhanced photocatalytic activity of Au@N-TiO2 can be responsible for the formation of an plasmonic photocatalyst and the formation of an impurity band between the conduction band (CB) and the valence band (VB) of TiO2.