Facile hydrothermal synthesis of alpha manganese sesquioxide (α-Mn2O3) nanodumb-bells: Structural, magnetic, optical and photocatalytic properties

► α-Mn2O3 nanoparticles sizes of 35-42 nm have been prepared by hydrothermal process. ► Shapes of α-Mn2O3: Dumb-bell, Cauliflower, spherical with rod, spherical with wires. ► The strong UV emission can be attributed to high purity and perfect crystallinity. ► Photocatalytic activity of α-Mn2O3 was studied by degradation of Remazol red B dye.