Sulfurization of hematite Fe2O3 and anatase TiO2 by annealing in H2S

Spray-deposited hematite Fe2O3 and spin-coated anatase TiO2 thin films were annealed under H2S in order to investigate the effect of sulfurization by H2S. Sulfurized films were characterized using UV-vis spectrophotometry, X-ray diffractometry, Raman spectroscopy, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Sulfurized Fe2O3 and TiO2 films are composed of multiple phases. The Fe2O3 film undergoes phase transformation from hematite into a mixture of magnetite (Fe3O4) and pyrrhotite (FeS) at annealing temperatures above 250 °C. At 450 °C α-Fe2O3 is fully transformed into pyrite (FeS2). The TiO2 film transforms into a mixture of TiO2 and TiS2. TiS2 formation begins at temperatures above 550 °C. At 700 °C, TiO2 is completely transformed into TiS2.