Facile synthesis of γ-MnOOH micro/nanorods and their conversion to β-MnO2, Mn3O4

Li, Fēi; Wu, Jianfang; Qin, Qing Hua; Li, Zhen; Huang, Xintang

doi:10.1016/j.jallcom.2009.11.089

Cited by 79 publications

(35 citation statements)

References 47 publications

(51 reference statements)

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“…The spectra of samples, annealed at 673, 723 and 773 K, are the simplest ones and contain two well-defined bands. The observed vibration frequencies are in very good agreement with the reported strongest bands for rod-like Mn 3 O 4 crystals (483 and 605 cm -1 [47], 503 and 609 cm -1 [48], 517 and 603 cm -1 [49]). These bands are assigned to coupling between Mn-O stretching modes of tetrahedral and octahedral sites.…”

Section: Resultssupporting

confidence: 88%

Synthesis and decomposition mechanism of γ-MnC2O4·2H2O rods under non-isothermal and isothermal conditions

Donkova

Avdeev

2015

J Therm Anal Calorim

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The thermolysis of the ill-known c-MnC 2 O 4 Á 2H 2 O is investigated applying DTA, TG, DSC, FT-IR, SEM, BET and Rietveld XRD phase analyses for thorough characterization of the starting compound and its calcined products. The dehydration proceeds in one step with DH = 149 kJ mol -1 (reported for the first time). Primary decomposition product is Mn 3 O 4 ([Mn 2? Mn 2 3? ]O 4 ) with high specific surface area. During its formation, the oxidation of Mn 3? species to Mn 4? starts, followed by oxidation of Mn 2? -Mn 3? , thus leading to formation of metastable Mn 5 O 8 ([Mn 2 2? Mn 3 4? ]O 8 ) and Mn 2 O 3 . Before complete precursor decomposition under non-isothermal conditions, the reduction of Mn 4? -Mn 3? occurs, forming an additional amount of Mn 3 O 4 . After isothermal annealing of c-MnC 2 O 4 Á2H 2 O in the range of 573-823 K, Mn 3 O 4 is detected as a major product in all samples. Mn 5 O 8 is identified after calcination at 573, 673, 723 K, and its amount decreases gradually in this order. Cubic Mn 2 O 3 appears after heat treatment at 673 K; its content varies between 13 and 23 % in the range of 673-773 K and becomes close to that of Mn 3 O 4 at 823 K. The application of the same experimental conditions as in the investigation of a-MnC 2 O 4 Á2H 2 O and MnC 2 O 4 Á3H 2 O allows an objective comparison of the nature and the peculiarities of the thermal decomposition of different crystal forms of manganese oxalate.

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Section: Resultssupporting

confidence: 88%

Synthesis and decomposition mechanism of γ-MnC2O4·2H2O rods under non-isothermal and isothermal conditions

Donkova

Avdeev

2015

J Therm Anal Calorim

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“…In recent years, the morphology and size controlled synthesis of materials have attracted much attention due to their unique chemical and physical properties that are relevant to the shape and size [1][2][3][4][5][6]. Considerable efforts have been devoted to synthesize novel nano-and microstructured materials with various morphologies, such as low-dimensional structures (e.g., rods [7], wires [8,9], belts [10], tubes [11]) and hierarchical structures (e.g., branches [12], urchins [13], hollow spheres [14,15]), for their specific properties and corresponding potential applications.…”

Section: Introductionmentioning

confidence: 99%

Bismuth tungstate nano/microstructures: Controllable morphologies, growth mechanism and photocatalytic properties

Tian

Hua

et al. 2011

Journal of Alloys and Compounds

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“…The BCM sample has weaker Mn-O bond in the Mn-O-Cu bridge, and stronger mobility and reactivity of the active oxygen species due to the high electronegativity of Cu. The vibrations above 800 cm -1 demonstrate the existence of the OH bonds, including c-OH (1,085 cm -1 ), d-2-OH (1,119 cm -1 ) and d-1-OH (1,151 cm -1 )[40]. In this region, the transmittance peaks of the K-birnessite sample are much stronger than those of the BCM sample.…”

mentioning

confidence: 92%

“…XRD FT-IR spectra of K-birnessite (a) and BCM (b) in the range of 450-1,700 cm -1 Reac Kinet Mech Cat 479 cm -1[37,38,40]. The band at 511 cm -1 is related to the asymmetric stretching vibrations of MnO 6 (Mn 4?…”

mentioning

confidence: 99%

Copper doped K-birnessite as an efficient catalyst for the synthesis of 2-aryl benzimidazoles

Eren

Gümüş

2014

Reac Kinet Mech Cat

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In this study, an efficient and highly selective synthesis of 2-aryl benzimidazoles from the reaction of o-phenylenediamine and aromatic aldehydes in the presence of birnessite type copper doped manganese oxide (BCM) is reported. BCM was synthesized by the one-step hydrothermal method. Recycling of BCM up to five runs was investigated with appreciable yield and selectivity of the products. The best overall yields and selectivities were obtained in methanol. The crystal structure and thermal stability of BCM are characterized by using XRD, IR and thermal analysis techniques. The acid sites of BCM were investigated by IR using pyridine as a molecular probe. The improved catalytic activity observed in the BCM catalyst was associated to a high lattice oxygen mobility and availability due to the formation of Cu-O-Mn bridges.

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Facile synthesis of γ-MnOOH micro/nanorods and their conversion to β-MnO2, Mn3O4

Cited by 79 publications

References 47 publications

Synthesis and decomposition mechanism of γ-MnC2O4·2H2O rods under non-isothermal and isothermal conditions

Synthesis and decomposition mechanism of γ-MnC2O4·2H2O rods under non-isothermal and isothermal conditions

Bismuth tungstate nano/microstructures: Controllable morphologies, growth mechanism and photocatalytic properties

Copper doped K-birnessite as an efficient catalyst for the synthesis of 2-aryl benzimidazoles

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