Manganese Oxide Phases Research Articles

Microstructural and Optical study of polycrystalline manganese oxide films using Kubelka-Munk function

Tetragonal Mn3O4 phase of manganese oxide with traces of cubic Mn2O3 was grown on p-type silicon (100) using pulsed laser deposition technique under different deposition temperatures ranging from 500 °C to 800 °C. Structural features and presences of different phases in thin films were obtained from X-ray Diffraction (XRD). The XRD pattern reveal the transformation of multi-phase tetragonal Mn3O4 and cubic Mn2O3 into single phase Mn3O4 at higher deposition temperature. As a result, the defect density reduced and crystalline quality improved. Optical band gap increased in single phase manganese oxide film, measured using UV-Vis Spectroscopy. A consistent increase in optical band gap, measured using Kubelka-Munk function, was observed in thin film samples with maximum value of 2.35 eV at 800 °C, a pre-requisite for many opto-electronics applications.

Regenerated Manganese-Oxide Coated Sands: The Role of Mineral Phase in Organic Contaminant Reactivity.

Manganese oxide-coated sand can oxidize electron-rich organic contaminants, but after extended exposure to contaminated water its reactivity decreases. To assess the potential for regenerating geomedia, we measured the ability of passivated manganese-oxide coated sand to oxidize bisphenol A after treatment with oxidants, acid, or methanol. Among the regenerants studied, KMnO4, HOCl, HOBr, and pH 2 or 3 HCl solutions raised the average oxidation state of the Mn, but only HOCl and HOBr restored the reactivity of passivated geomedia to levels comparable to those of the virgin manganese-oxide coated sand. Treatment with HCl restored about one third of the reactivity of the material, likely due to dissolution of reduced Mn. Mn K-edge X-ray absorption spectroscopy data indicated that the reactive manganese oxide phases present in virgin geomedia and geomedia regenerated with HOCl or HOBr had nanocrystalline cryptomelane-like structures and diminished Mn(III) abundance relative to the passivated geomedia. KMnO4-regenerated geomedia also had less Mn(III), but it exhibited less reactivity with bisphenol A because regeneration produced a structure with characteristics of δ-MnO2. The results imply that manganese oxide reactivity depends on both oxidation state and crystal structure; the most effective chemical regenerants oxidize Mn(III) to Mn(IV) oxides exhibiting nanocrystalline, cryptomelane-like forms.

Precursor Effect on Mn-Fe-Ce/TiO2 Catalysts for Selective Catalytic Reduction of NO with NH3 at Low Temperatures

Preparation of Mn/TiO2, Mn-Fe/TiO2, and Mn-Fe-Ce/TiO2 by the deposition-precipitation (DP) method can afford very active catalysts for low-temperature NH3-SCR (selective catalytic reduction of NO with NH3). The effect of precursor choice (nitrate vs. acetate) of Mn, Fe, and Ce on the physiochemical properties including thermal stability and the resulting SCR activity were investigated. The resulting materials were characterized by N2-Physisorption, XRD (Powder X-ray diffraction), XPS (X-ray photoelectron spectroscopy), H2-TPR (temperature-programmed reduction with hydrogen), and the oxidation of NO to NO2 measured at 300 °C. Among all the prepared catalysts 5MnAce/Ti, 25Mn0.75AceFe0.25Nit/Ti, and 25Mn0.75AceFe0.20NitCe0.05Ace/Ti showed superior SCR activity at low temperature. The superior activity of the latter two materials is likely attributable to the presence of amorphous active metal oxide phases (manganese-, iron- and cerium-oxide) and the ease of the reduction of metal oxides on TiO2. Enhanced ability to convert NO to NO2, which can promote fast-SCR like pathways, could be another reason. Cerium was found to stabilize amorphous manganese oxide phases when exposed to high temperatures.

Effect of 1D diffusion channel size and ionic content on Li+ ion and Na+ ion diffusion in tunnel manganese oxides

The conduction of both electrons and cations is important for battery electrode materials to deliver high capacities at higher current rates. Here, we investigate the ion diffusion and electronic conductivities of three tunnel manganese oxide phases with different size structural tunnels and templating cations for use as Li-ion and Na-ion battery (LIB and SIB) electrodes. The galvanostatic intermittent titration technique is used to measure the apparent diffusion coefficients of Li+ ions and Na+ ions in each material, and a four-point probe technique is used to measure the electronic conductivity of each phase. It is found that in LIBs, the material with the largest tunnels and greatest volume available for Li+ ion intercalation demonstrated the highest DLi+ value, correlating with the highest performance at the highest current rate used in this work. In SIBs, however, it is not the material with the largest tunnels that demonstrates the highest rate performance. Rather, it is the material templated by Na+ ions, the same ions as the electrochemically cycled charge carriers. These results highlight the importance of the relationship between the structural tunnel size, nature of templating ions and charge-carrying ion size and provide insights into the design of electrode material for improved energy storage systems.

Effect of the valence state of Mn in MnO x /Ti4O7 composites on the catalytic performance for oxygen reduction reaction and oxygen evolution reaction.

Manganese oxide composites with mixed valence states were prepared through the hydrothermal method by compositing with Ti4O7 and calcining at different temperatures, and their ORR and OER catalytic performance were investigated. The prepared catalysts were characterized by XRD, SEM-EDS, HRTEM-EDS, and XPS methods to analyse their phase constitution, morphology feature, and surface composition. The major phase of manganese oxides was Mn3O4, which is a one-dimensional structure, and its growth was induced by Ti4O7. The ORR and OER catalytic activity can be enhanced due to the preferred orientation of manganese oxides. Electrochemical measurements, namely CV, LSV and EIS, were utilized for determining the ORR and OER catalytic activity, whereas CA and ADT were used for studying the durability and stability. A Li–O2 battery was assembled to test the electrochemical behavior and properties in practical application. MnOx/Ti4O7 calcined at 300 °C exhibited the best catalytic activity of 0.72 V vs. RHE half-wave potential for ORR and 0.67 V vs. RHE overpotential for OER. The proportion of Mn3+ was also highest in all the MnOx/Ti4O7 composites. The assembled Li–O2 battery shows high performance with a voltage gap of only 0.85 V. Therefore, it can be affirmed that the inducement of Ti4O7 could strengthen the preferred orientation in manganese oxide growth and Mn3+ in MnOx/Ti4O7 plays a vital role in catalyzing ORR and OER, with both improving the ORR and OER bifunctional catalytic performance of manganese oxides.

Volatilization Behavior of Manganese from Molten Steel with Different Alloying Methods in Vacuum

The volatilization loss of manganese during the vacuum smelting process is one of the key factors that determines the manufacturing cost and quality of manganese steel. In this study, the laboratory experiments and thermodynamic calculations were performed to investigate volatilization behavior of manganese from molten steels with different alloying methods in vacuum process. Based on the thermodynamic analysis, with the increase of manganese content, the partial vapor pressure of the manganese component increased, resulting in manganese being easily volatilized from molten steel. The carbon content in the steel shows an evident influence on partial vapor pressure of manganese component, and a higher carbon content in steel leads to a lower partial vapor pressure of manganese, but it not influenced by the silicon content. Compared with the alloying method of high carbon ferromanganese, the volatilization loss of manganese in the alloying method of silicon manganese presents faster decay, agreeing well with the thermodynamic analysis. Besides, the volatile fraction generated in the alloying method of high-carbon ferromanganese is composed of a large amount of MnO nanorods with a lateral length approximately 500 nm and a small number of Mn3O4/Mn nanoparticles with a diameter less than 500 nm. Additionally, the volatile fraction generated in the alloying method of silicon manganese shows Mn3O4 nanoparticles as the main phase. It can be inferred that the existence of the manganese oxide phase is attributed to the high chemical activity of nanoscale particles within air.

Strong interfacial charge transfer between hausmannite manganese oxide and alumina for efficient photocatalysis

Well crystalline manganese oxide (Mn3O4) nanoparticles anchored on gamma alumina (γ-Al2O3) have been successfully tailored via a proficient and cost effective chemical process as an efficient material for photo catalysis. XRD indicated the composite formation of γ-Al2O3 and hausmannite structure of Mn3O4. SEM and TEM revealed that hetero structure of Mn3O4/γ-Al2O3 exhibits an amalgam of aggregated nanoparticles and nanorods. XPS demonstrated the chemical states of binary nanocomposite. The band gap tuning has been performed with γ-Al2O3 nanoparticles by assimilating hausmannite Mn3O4 particles into flower like microstructure of Al2O3. The photoluminescence spectra affirmed the enhancement in charge separation in Mn3O4/γ-Al2O3 binary hybrid photocatalyst. The band gap becomes narrow with the increase in concentrations of Mn3O4. The narrowing of band gap is concorded with crystalline domains of primary aggregated particles. To elucidate the mechanism of the photocatalytic activity linear sweep voltammetry was performed. The results showed that Mn3O4/γ-Al2O3 nanocomposite revealed the enhancement in current density as compared to pure γ-Al2O3 which confirmed the electron transfer from Mn3O4 to γ-Al2O3 through the interfacial potential gradient in conduction bands. The optimum concentration of 6.0% Mn3O4/γ-Al2O3 for hybrid structure showed an excellent photocatalytic activity under visible light due to narrow band gap energy. High degree distribution of Mn3O4 nano architects overlying on γ-Al2O3 induces a significant synergic effect between γ-Al2O3 and hausmannite phase of manganese oxide (Mn3O4). This strong interfacial contact between γ-Al2O3 and Mn3O4 endures the quick transfer of photo generated charge carriers across interface.

Sol-gel synthesis and photocatalytic activity of biomimetic calcium manganese oxide catalysts

The water contaminations by dye residues are increasingly becoming serious concerns worldwide due to dye toxicity and persistent characteristics. Manganese oxide-based catalysts having similar structures with manganese compounds found in nature (biomimetic) have been considered as a very promising and effective photocatalyst for the degradation of organic pollutions in wastewater. This paper focuses on the synthesis of calcium manganese oxide catalysts from the octahedral layered birnessite-type manganese oxide and calcium carbonate via sol-gel method with citric acid as the complexing agent. The as-synthesized oxide was then tested as a photocatalyst for the degradation of methylene blue (MB) dye. The calcium manganese oxides prepared by the two different mole ratios of CaCO3/MnO2 resulted in the similar crystallinity and crystal phases but difference in the crystal sizes. The photocatalytic activities of the prepared calcium manganese oxides for the degradation of methylene blue are compared to that of the calcium manganese oxide prepared from tunnel cryptomelane-type manganese oxide. Both the calcium manganese oxides prepared from the different manganese oxide phases show the remarkable performance for the photocatalytic degradation of methylene blue after 10 minutes of reaction times. The birnessite-prepared calcium manganese oxide displays slightly higher photocatalytic performance than cryptomelane-prepared calcium manganese oxide.

Shape Modification of Manganese Oxide Prepared by Solvothermal: Effect of Precipitation Agent

Nano-sized manganese oxide was synthesized by the solvothermal method. Manganese sulfate was used as a precursor, which is obtained from the Sumbawa manganese ore. Two kinds of the precipitating agent, ammonium persulfate and sodium hydroxide, were used in this study and the effect on the solvothermal product were examined thoroughly. The solvothermal temperature and time were 120°C for 18 hours, respectively, for both precipitating agents. The results showed that the phase of manganese oxide was influenced by the precipitating agent, as indicated by X-ray diffraction analysis. Phase <x-MnO2 was obtained from the reaction between MnSO4 and ammonium persulfate, while Mn3O4 for the sodium hydroxide. The formation of a-MnO2 was influenced by the excess of NH4 + which came from the manganese ore leaching into MnSO4. One notable finding in this study is that the morphology of manganese oxide was also affected by the precipitating agent. For instance, the shape of MnO2 and Mn3O4 was needle and sphere, respectively. Moreover, the strict long thinner needle of <x-MnO2 was formed and the aspect ratio increased at a higher temperature. While the particle size of Mn3O4 decreased with the increased temperature. These results imply that variation of a precipitating agent is imperative to obtain the specific manganese oxide product, including the shape.

A study of calcium ion intercalation in perovskite calcium manganese oxide

Abstract We report on the synthesis and characterization of perovskite calcium manganese oxide (CaMnO3) as an intercalation compound for calcium ion insertion and extraction. Cyclic voltammetry measurements indicate calcium ion insertion and de-insertion into and from the CaMnO3 host. Differential capacity analysis delineates the potentials at which the insertion and extraction redox processes occur (at −0.4 V and + 0.1 V vs. Ag/Ag+, respectively). The insertion and extraction of calcium ions is supported by post-mortem x-ray analysis, which indicates loss of Ca2+ ions from the native CaMnO3 phase as well as the presence of manganese oxide phases. This study shows that perovskite calcium manganese oxide is a promising intercalation host.

Different Phase and Morphology Effect of Manganese Oxide on Electrochemical Performance for Supercapacitor Application

Nanostructures of manganese oxides are a promising pseudocapacitive electrode material due to its eco-friendly, low cost, and intrinsically high capacity. In this work, we prepared monometallic manganese oxide Mn3O4, and MnO2 using a facile, one-step hydrothermal method at low processing temperature. The structural, morphological, elemental analysis of manganese oxide (Mn3O4 nanoparticles (NPs) and one-dimensional MnO2 nanowires (1-D NWs)) powders confirmed from XRD, TEM, SEM, and EDAX techniques. The prepared materials have the same crystal structure with different phase and morphology. The morphology information of prepared Mn3O4, MnO2 powders visualized from an electron microscope of TEM and SEM techniques as particle and wire type morphology. The electrochemical performance of fabricated individual Mn3O4 and MnO2 @ Ni foam electrodes exhibited specific capacitance around 182 and 243 F/g at a current density of 0.5 A/g from galvanostatic charge–discharge cycles measurement in presence of 1 M KOH compared with 0.5 M KOH electrolyte solution. Also, from these results, the morphology of MnO2 (NWs) has better specific capacitance than Mn3O4 (NPs) in 1 M KOH electrolyte solution.

Thermally activated structural transformations in manganese oxide nanoparticles under air and argon atmospheres

The properties of manganese oxide nanomaterials are dictated by the structure and morphology of the particular phases they can adopt. In this work, the effects of post-synthesis heat treatments on amorphous monodisperse manganese oxide nanoparticles at temperatures of up to 1300 °C under laboratory air and argon atmospheres have been investigated using X-ray diffraction, thermal analysis, and electron microscopy techniques. During heat treatments in air, the nanoparticles undergo three transformations, resulting in: crystallization to cubic Mn2O3 at ~ 500 °C, followed by the transformation to tetragonal Mn3O4 at ~ 1010 °C, and to cubic Mn3O4 at ~ 1190 °C. The first two transformations are irreversible, are associated with oxygen loss, and involve reductions of the Mn ions. The latter transformation is polymorphic and spontaneously reversible, and so, tetragonal Mn3O4 is observed at ambient temperature in samples heat-treated at above 1000 °C. The samples heat-treated in argon firstly crystallize to a mixture of monoclinic Mn2O3 and tetragonal Mn3O4 at ~ 475 °C, followed by complete transformation to tetragonal Mn3O4 at ~ 820 °C, and then to mostly cubic MnO at ~ 1145 °C; here again, the residual tetragonal Mn3O4 undergoes a reversible polymorphic transformation at ~ 1180 °C, whereas the other transformations are irreversible. In both atmospheres, the amorphous material exhibits short-range cryptomelane-type order with a mixture of Mn3+ and Mn4+ prior to crystallization. These data indicate that most of the stable manganese oxide phases can be obtained from initially amorphous nanoparticles by heat treatment under appropriate conditions.

Mineralogy, geochemistry and genesis of the post-Gondwana supergene manganese deposit of the Carletonville-Ventersdorp area, North West Province, South Africa

The post-Gondwana period is characterized by some of the unique geologic events which shaped the present geomorphological landscape in various parts of the world. One of the most important and unique features associated with this geologic period is the formation of high valence state (Mn4+) manganese oxides in weathering crusts of uplifted landscapes, underlain by manganiferous protores. The study of these manganese oxide minerals has proven not only to be industrially beneficial but they also provide insights into the evolution of the paleo surfaces, especially in tropical regions. Here we present new results on mineralogy, geochemistry and genetic model of the North West Manganese Deposit in the General Nice lease area. The General Nice ore deposit represents a near surface accumulation of supergene manganese wad and nodule deposit in a weathering crust underlain by manganiferous dolostones of the Transvaal Malmani Subgroup. The ore formation is attributed to in situ dissolution, leaching and surficial weathering of the underlying manganiferous dolostones of the Malmani Subgroup and carbonaceous protore of the Waterval Saprolite in a typically oxidic lacustrine setting. The combined processes led to the release and mobilization of Mn rich colloidal particles (sols) into the overlying water column of the depository, which later precipitated as manganese nodules upon interaction with the alluvial sediments which acted as substrates and centers of accretion. Mineralogical studies conducted on both scanning electron microscope (SEM –EDS) and X-ray diffraction (XRD) indicated the predominance of the manganese oxides; romanechite, cryptomelane and galaxite as major manganese oxide phases and pyrolusite, vernadite occurring in minute quantities. Diagenetic features indicate alteration of pyrolusite and its replacement by romanechite. This is evident from the romanechite veinlets cross-cutting the fractured groundmass of pyrolusite. Galaxite appears to represent the latest stage of authigenic mineral precipitation, and occurs mostly around the pore-spaces. Other mineral components include hematite/goethite, clays, muscovite, silica and inclusions of ilmenite and detrital zircon. These accessory minerals occur either in the form of nuclei grains or inclusions in manganese oxide cement.

Microstructure and dielectric properties of LiTaO3 ceramics with MnO2 addition fabricated by hot-pressing sintering

Lithium tantalite (LiTaO3) is an excellent single crystal, only a few studies focused on polycrystalline LiTaO3 ceramics, because it is difficult to sintering densification in fabrication process by common sintering. In this paper, LiTaO3 composite ceramics with added 3 wt% MnO2 were obtained by hot-pressing sintering at different temperatures from 1200 to 1350 °C. The sinterability, microstructure and dielectric properties of LiTaO3 ceramics fabricated at sintering temperatures were investigated. The relative density of the LiTaO3 ceramics was significantly enhanced as the sintering temperature increases first and then decreased. The LiTaO3 ceramics achieved the highest relative density (98.6%) and shown homogeneous microstructure when sintered at 1300 °C. The LiTaO3 and manganese oxide phases were observed in the MnO2/LiTaO3 ceramics fabricated at different sintering temperatures. The dielectric properties of MnO2/LiTaO3 ceramics were significantly influenced by the sintering temperatures. The study of dielectric properties revealed that the specimen had excellent dielectric properties when sintering temperature was 1300 °C and the dielectric constant was 78, as it tends to stay invariable at room temperature.

MnO2 fiber as a sorbent for radionuclides in oceanographic investigations

The paper presents the results of a study of the physical, chemical and sorption properties of a fibrous sorbent—polyacrylonitrile modified with a mixed phase of manganese oxide, in relation to the natural isotopes of radium in seawater. The paper contains methodical guidelines for synthesizing the material the most efficiency and hydromechanical stability. It is described using structural (diffractometry, IR spectroscopy) and physicochemical methods of analysis (thermal analysis, gas adsorption). The possibility of using this sorbent for the concentration of cosmogenic (7Be) and natural (226Ra, 228Ra, 234Th) radionuclides from seawater samples under field conditions was studied. The results of determination of the concentration of dissolved 226Ra, 228Ra, 234Th in seawater samples using this sorbent were compared with the published data. Evidence of sorption 7Be from seawater samples using this fiber was obtained by γ-spectrometric analysis.

Yttrium Manganese Oxide Phase Stability and Selectivity Using Lithium Carbonate Assisted Metathesis Reactions.

In solid-state chemistry, stable phases are often missed if their synthesis is impractical, such as when decomposition or a polymorphic transition occurs at relatively low temperature. In the preparation of complex oxides, reaction temperatures commonly exceed 1000 °C with little to no control of the reaction pathway. Thus, a prerequisite for exploring the synthesis of complex oxides is to identify reactions with intermediates that are kinetically competent at low temperatures, as provided by assisted metathesis reactions. Here, we study the assisted metathesis reaction Mn2O3 + 2.2YCl3·6H2O + 3Li2CO3 → 2YMnO3 + 5.8LiCl + 0.2LiYCl4 + 3CO2 using in situ synchrotron X-ray diffraction. By changing the atmosphere, oxygen vs inert gas, the reaction product changes from the overoxidized perovskite YMnO3+δ to the hexagonal YMnO3 polymorph at the reaction temperature of 850 °C, respectively. Analysis of the reaction pathways reveals two parallel reaction pathways in forming YMnO3 phases: (1) the slow reaction of metal oxides in a LiCl flux (Y2O3 + Mn2O3 [Formula: see text] 2YMnO3) and (2) the fast reaction from ternary intermediates (YOCl + LiMnO2 → LiCl + YMnO3). Control reactions reveal that both proposed pathways in isolation result in product formation, but the direct preparation of ternary intermediates (YOCl + LiMnO2 → LiCl + YMnO3) occurs at lower temperatures (500 °C) and shorter times (<24 h) and forms nominally stoichiometric orthorhombic YMnO3. These ternary intermediates react at a faster rate than the slow stepwise oxygenation of yttrium chloride to Y2O3 (YCl3 → YOCl → Y3O4Cl → Y2O3), which is relatively inert. These results support a kinetically controlled reaction pathway to form YMnO3 phases in assisted metathesis reactions with phase selectivity achievable through changes to reaction atmosphere.

Synthesis and Catalytic Activities of Manganese Oxides Prepared by Precipitation Method: Effects of Mixing Modes of Reactants and Calcination Process

The two phases of manganese oxides are prepared by two different mixing modes using the same precipitation method from the solutions of KMnO4 dan maltose, resulting in marked different phase structures and catalytic activities. The oxides synthesized by adding dropwise of the maltose solution into KMnO4 solution (method A) resulted in the formation of layer manganese oxide birnessite, which turns into tunnel structured manganese oxide cryptomelane following the calcination at 600°C for 4 hours. The simultaneous addition of KMnO4 solution and maltose solution (method B) also produced birnessite before calcination, but remain unchanged as birnessite phase after calcination with cryptomelane as minor product. The samples without calcination obtained from method A posseses higher surface area and poor crystallinity compared to that with calcination. The catalytic test using Fenton-like Reaction for methylene blue (MB) degradation indicated the tremendeous difference in their catalytic activities for both samples without and with calcination. The birnessite catalysts (without calcination) prepared using method A show the highest activity and are able to degrade 93% methylene blue within 10 minute, much higher than other samples.

Lithiation Kinetics in Silicon/Mn3O4 Core–Shell Nanoparticles Anodes for Li-Ion Battery

Silicon is predicted to become a significant component of high energy density Li-ion anodes. Mn-based cathodes for Li-ion batteries have been widely investigated in past years and Mn dissolution into the electrolyte, migration, and deposition on the anode’s solid electrolyte interphase present a major challenge. In this work, we intentionally synthesize manganese oxide with several nanoscale thicknesses on a Si nanomaterial and follow the electrochemical behavior of the core–shell nanoparticles as Li-ion anode. The structure of the nanocomposites is investigated using high-resolution scanning electron microscopy, high-resolution transition electron microscopy, X-ray diffraction, and electron paramagnetic resonance. The synthesis yields uniform nanoshells of Mn3O4 haussmanite phase. We demonstrate that the haussmanite phase is electrochemically active, and its presence improves the lithiation process during cycling. This study reveals that the formation of a thin shell of manganese oxide phase on Si anode can improve the lithiation kinetics of the Si nanomaterials, while a thicker shell slows down the kinetics. In summary, to a certain extent, the contamination of Si anode materials from Mn-based cathodic materials could have a positive impact on their electrochemical behavior.

Synthesis of nanosize manganese oxides from its ore using solvothermal method

Nano-sized manganese oxide was successfully synthesized from local manganese ore using solvothermal method. The manganese ore were obtained from Jereweh District, Sumbawa, West of Nusa Tenggara, Indonesia. The aims of this research are to study the effects of temperature and time to the morphology, size and phase of manganese oxide obtained by solvothermal method. In the first step, we performed the extraction of manganese precursor from manganese ore. The method to extract the manganese precursor was hydrometallurgy. The second step, manganese precursor that obtained in the first step was used to synthesis manganese oxide using solvothermal method. NaOH was used as precipitating agent. The phase, morphologies and particle size of manganese oxides were examined by x-ray diffractometer and scanning electron microscopy.

Activity of manganese oxides supported on halloysite towards the thermal catalytic oxidation of formaldehyde: Constraint from the manganese precursor

Mn-based catalysts have been widely studied for the oxidation of volatile organic compounds (VOCs) and appear to be the most active catalysts among the transition metal oxides. In this study, manganese oxides are supported on halloysite, a nanoscale and porous clay mineral, by an impregnation method using manganese nitrate, manganese acetate, and potassium permanganate as precursors. The nitrate results in scattered 35–249 nm agglomerates of pyrolusite (β-MnO2) on the external surface of the halloysite nanotubes; the acetate produces hausmannite (Mn3O4) particles with sizes of 15–40 nm dispersed on the external surface, while the permanganate creates nanoparticles and agglomerates of amorphous K-containing MnO2 on the external surface as well as in the lumen. These differences in structure and distribution are related to the oxidizability of the precursor, surface charge and the cylindrical lumen of halloysite, and the interaction between manganese ions (Mn2+ or MnO4−) and the surface groups of halloysite (SiOSi or AlOH). The obtained samples were tested for the thermal catalytic oxidation of formaldehyde. The halloysite-supported manganese oxide with the permanganate precursor exhibits the best activity and achieves 90% of CO2 generation at 149 °C. The activity of formaldehyde oxidation is positively correlated to the reducibility, which depends on the phase, oxidation state, and dispersion of manganese oxides. This study illuminates the constraint of the manganese precursor on halloysite-supported manganese oxides for the thermal catalytic oxidation of formaldehyde and will be beneficial for the development of transition metal oxide-based catalysts in the abatement of VOCs.