Construction of Fe-doped TiO2−x ultrathin nanosheets with rich oxygen vacancies for highly efficient oxidation of H2S

[Display omitted] •Defect-rich Fe-doped TiO2−x with ultrathin nanosheets structure was synthesized.•Fe-doping effect on structural defects and surface chemistry was demonstrated.•Fe-doped TiO2−x nanosheets displayed superior performance among TiO2 catalysts.•In situ studies of DRIFTS, EPR and Raman spectra of H2S oxidation were performed.•The reaction pathway of Fe-doped TiO2 catalysts for H2S oxidation was proposed. Introduction of surface oxygen vacancy (Vo) has been proved to be a powerful method to promote the performance of H2S selective oxidation by improving H2S adsorption and O2 activation. Nevertheless, maximizing the oxygen vacancy concentration remains a challenge due to limited exposed surface. Herein, we report a Fe-doped TiO2−x ultrathin nanosheet with abundant oxygen vacancies for H2S selective oxidation via a facile citric acid assisted hydrothermal process. One of the cheapest and most abundant metals, iron, is a desirable dopant for further promoting the H2S oxidation activity of TiO2. As a result, the Fe-doped TiO2−x nanosheets endowed with abundant oxygen vacancies exhibited nearly 100% H2S conversion and sulfur selectivity at 210 °C and is superior to those of most reported Ti-based materials. Furthermore, through in situ DRIFTS, in situ Raman and EPR spectra of H2S oxidation, the reaction pathway for selective oxidation of H2S over Fe-doped TiO2−x with abundant oxygen vacancies was revealed. The density functional theory (DFT) calculations were conducted to get a deeper insight into the effect of Fe-doping on the electronic structure and oxygen vacancy of defected TiO2.