Synergistic effect on the photocatalytic activity of N-doped TiO₂ nanorods synthesised by novel route with exposed (110) facet

This paper describes a facile route for the preparation of visible-light-active N-doped TiO₂ nanorods arrays at low temperature by a template-free oxidant peroxide method (OPM) and crystallized under hydrothermal treatment. The samples were characterized for structural, morphological and optical properties by XPS, FE-SEM, HRTEM, XRD, Raman and UV–vis spectroscopy. XPS analysis revealed that N dopant atoms were mainly added at the interstitial sites into TiO₂ lattice structure and few N atoms were present as substitutional sites of nitrogen atoms and/or at molecularly chemisorbed γ-N₂ molecules. FE-SEM and HR-TEM analyses show that doping does not influenced the cylindrical architecture of the nanorods. However, N doping causes an obvious red shift in the band edge which increases visible region absorption. The photocatalytic activity of pristine and N-doped TiO₂ photocatalysts was tested for the degradation of methyl orange (MO) under UV and visible light irradiation. The N-doped TiO₂ photocatalysts showed an efficient photocatalytic activity for methyl orange degradation under UV and visible-light irradiation as compared to pristine TiO₂. Multiple cycles for the MO photodegradation were performed without a decrease in the photocatalytic activity. PEC studies showed that photocurrent densities of 8.2 μA cm⁻² and 7.0 μA cm⁻² were obtained under UV and visible-light illumination at a potential of 0.8 V. - Highlights: • The pristine and N-doped TiO₂ nanorods were prepared and characterized for structural and optical properties. • As-prepared samples showed enhanced photocatalytic activity toward the photodegradation of MO dye. • Photo-electrochemical measurements were done to investigate N-doped TiO₂ nanorods capability for water splitting.