Physicochemical properties of MnTiO3 powders obtained by molten salt method

Abstract Pure manganese titanate (MnTiO3) powder was successfully synthesized by means of the molten salt method, at 1000 °C for 3 h. The effect of salts used during the synthesis process was evidenced by X-ray diffraction (XRD). Structural parameters were calculated by the Rietveld refinement, where a crystallite size of 292 nm was estimated. Ultraviolet–Visible (UV–Vis) spectroscopy showed that MnTiO3 displays a wide light absorption range, from 200 nm to 800 nm. Through first-principles calculations, the band structure and density of states for ilmenite-type MnTiO3 were estimated, where an indirect band gap of 3.4 eV was obtained. Atomic composition and chemical bonds were determined by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR), respectively. Electrochemical properties of MnTiO3 were analyzed using the Mott-Schottky curve, where an n-type semiconducting behavior and a flat band potential ( E f b ) of 1.41 V (vs NHE at pH = 0) were observed.