Nanostructured N-doped TiO2 marigold flowers for an efficient solar hydrogen production from H2S

Abstract

Nitrogen-doped TiO₂ nanostructures in the form of marigold flowers have been synthesized for the first time using a facile solvothermal method. The structural analysis has shown that such an N-doped TiO₂ system crystallizes in the anatase structure. The optical absorption spectra have clearly shown the shift in the absorption edge towards the visible-light range, which indicates successful nitrogen doping. The nitrogen doping has been further confirmed by photoluminescence and photoemission spectroscopy. Microscopy studies have shown the thin nanosheets (petals) of N–TiO₂ with a thickness of ∼2–3 nm, assembled in the form of the marigold flower with a high surface area (224 m² g⁻¹). The N–TiO₂ nanostructure with marigold flowers is an efficient photocatalyst for the decomposition of H₂S and production of hydrogen under solar light. The maximum hydrogen evolution obtained is higher than other known N–TiO₂ systems. It is noteworthy that photohydrogen production using the unique marigold flowers of N–TiO₂ from abundant H₂S under solar light is hitherto unattempted. The proposed synthesis method can also be utilized to design other hierarchical nanostructured N-doped metal oxides.