Estimation of hydrothermally synthesized Iron incorporated 2D-sheet-like α-MoO3microstructural and optical parameters treated by annealing temperature

Abstract

In this article, pure and Fe-doped (5 wt.%) α-MoO3 nanosheets have been synthesized by hydrothermal approach and doped nanosheets were further annealed (at Ta = 600 °C and Ta = 700 °C temperatures for 3 hrs) for improved crystalline properties. The XRD analysis revealed the formation of orthorhombic structure without tracing of impurities or secondary phases. The iron dopant and annealing temperatures improved the crystallinity as the crystallite size increased. The pristine sample consists with randomly oriented nanosheets with an average width of 100-200 nm and length of several micrometers. Doping with iron does not induce any noticeable effect on morphology of α-MoO3, as revealed by FESEM imaging. The doped nanosheets form a large, rectangular plate-Type layered structure at 600 °C. Nanosheets with more developed and smooth surfaces with sharp corners and edges were observed at an elevated temperature of 700 °C. EDX study confirmed the Fe incorporation. The presence of different functional groups was analyzed by FTIR spectra. As a result of Fe doping, the band gap has decreased by 10% from an intrinsic value of ∼3.00 eV. The thermal annealing step further modifies the optical bandgap, providing an extracted value of 2.85 eV in this study.