Shape‐controlled Synthesis of Nanostructure Ramsdellite‐type Manganese Oxide at Atmospheric Pressure

Abstract

Ramsdellite (R-MnO 2 ) was prepared by oxidizing bivalent manganese salts, such as MnCl 2 , MnSO 4 and Mn(NO 3 ) 2 , with NaClO solution using a refluxing process at atmospheric pressure. The products were characterized by X-ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and flame photometry. R-MnO 2 microstructure and morphology were controlled by adjusting reaction temperature, the amount of hydrochloric acid (HCl) and anions of bivalent manganese salts. Ramsdellite grain was formed with three different bivalent manganese salts oxidized by NaClO solution at 60 ℃, and increased with the increase of reflux temperature. R-MnO 2 nanorod and nanowire crystals were obtained when MnCl 2 and MnSO 4 were used as bivalent manganese salts at 100 ℃ respectively. Nanosized flake of R-MnO 2 came into being when Mn(NO 3 ) 2 was applied at 80 ℃. When 30 mmol MnCl 2 was oxidized by 60 mmol NaClO solution with adding 20 mmol HCl in refluxing solution, specific surface area of R-MnO 2 grain obtained at 60 ℃ was greater than 140 m 2 /g, and the self-assembly of nanorod bundles into interesting flowerlike architectures was achieved at 100 ℃.The process of dissolution-precipitation equilibrium might be the primary cause for the morphology transformation.

Cyclometalated Platinum(II) Terpyridylacetylide with a Bis(arylamine) Donor as a Proton-Triggered Luminescence Chemosensor for Zn2+

“…Syntheses of 4-( p -bromophenyl)-6-phenyl-2,2′-bipyridine, 4-phenyl-6-phenyl-2,2′-bipyridine (ph-C^N^N), [(ph-C^N^N)­Pt­(CC–C 6 H 5 )], a 4′-phenyl-2,2′:6′,2″-terpyridine (ph-TPY), [Zn­(ph-TPY) 2 ]­(PF 6 ) 2 , N′-( tert -butoxycarbonyl)- N ′-(phenyl)- p -phenylenediamine, and N , N ′-dibutyl- N , N ′-diphenyl- p -phenylene-diamine have been described previously.…”

Manganese Oxide Nanoparticles: An Insight into Structure, Synthesis and Applications

“…The description of some of the polymorphs of manganese oxide nanomaterials from literature has been given in Tab. 1 [17,[39][40][41][42][43][44][45][46][47]. For a more thorough study of crystal structures, one can go through Ref.…”

Facile hydrothermal synthesis and electrochemical properties of orthorhombic LiMnO2cathode materials for rechargeable lithium batteries

“…The addition of AlCl 3 consumed OH À to form AlO 2 À , and also affected the oxidation capacity of NaClO in strong alkaline solution systems. 22,23 The preparation of doped o-LiMnO 2 by one-step hydrothermal synthesis was seldom reported, which was likely due to the precipitation reaction of metal cations and hydroxide ions. In this work, soluble AlO 2 À was formed using AlCl 3 in LiOH solution of high concentration.…”

“…Under reuxing conditions, sodium hypochlorite (NaClO) could oxidize Mn(II) source to form uniform ramsdellite-type manganese oxide with various morphologies. 22 MnPO 4 $H 2 O and hureaulite containing low-valent Mn(III/II) can also be fabricated by adjusting reactant ratios and reaction temperatures. 22,23 Our previous studies have suggested that manganese minerals with different oxidation states of manganese could be formed when NaClO worked as oxidant.…”

“…22 MnPO 4 $H 2 O and hureaulite containing low-valent Mn(III/II) can also be fabricated by adjusting reactant ratios and reaction temperatures. 22,23 Our previous studies have suggested that manganese minerals with different oxidation states of manganese could be formed when NaClO worked as oxidant.…”