Single crystalline manganite (γ‒MnOOH) rods enclosed with high index facets and its excellent catalytic conversion of lignin‒derived feedstock

Abstract

Single crystalline manganite (γ‒MnOOH) materials with rod shape have been synthesized via hydrothermal method. Interestingly, the extent of the hydrothermal duration of the syntheses had a significant impact on the crystal's growth of manganite rather than morphogical or phase tuning. Hydrothermal duration and amount of SDS had a significant impact on the crystal's growth. During synthesis, SDS template preferentially bind on the (111) than (101) surface. The rod shaped manganite has been identified by powder X‒ray diffraction (XRD), Raman spectroscopy, high‒resolution transmission electron microscopy (HRTEM), field‒emission scanning electron microscopy (FESEM), and X‒ray photoelectron spectroscopy (XPS) studies. PXRD and HR TEM techniques were shown that the rod shaped manganite are single crystalline in nature. FESEM, HRTEM and SAED techniques revealed that the rod shaped manganite were enclosed with {11‒1}, {‒111}, {111} and {110} exposed facets. XPS analysis revealed that Mn exhibits a mixed‒valence state (Mn3+ and Mn4+) at the surface of the rods. The rods exhibit good catalytic activities towards the oxidation of isoeugunol (lignin‒derived feedstock) to vanillin.