Enhanced electrochemical property of SILAR-deposited Mn3O4 thin films decorated on graphene

Nkele, Agnes C.; Chime, Ugochi K.; Ezealigo, Blessing N.; Nwanya, Assumpta C.; Agbogu, AdaN.C.; Ekwealor, A. B. C.; Osuji, R. U.; Ejikeme, Paul M.; Maaza, M.; Ezema, Fabian I.

doi:10.1016/j.jmrt.2020.06.031

“…The obtained films showed different specific capacitance values through electrochemical transformation (72 to 393 F/g) and chemical transformation (72 to 258 F/g). Enhanced physical properties (from amorphous to crystalline, irregularly fused capsule-like grains) improved the band gap and transmittance of SILAR-deposited Mn 3 O 4 films decorated on graphene [170]. The films showed the highest specific capacitance (194 F/g), indicating these materials could be used in electrochemical storage devices.…”

Section: Manganese Oxide Filmsmentioning

confidence: 99%

Recent Advances in the Growth and Characterizations of SILAR-Deposited Thin Films

Soonmin

¹

2022

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Many researchers have reported on the preparation and characterization of thin films. The prepared thin films could be used in lasers, cathodic ray tubes, solar cells, infrared windows, ultraviolet light emitting diodes, sensors, supercapacitors, biologic applications, and optoelectronic applications. The properties of these thin films strongly depend on the deposition techniques. Throughout the years, many investigations into the production of various types of thin films (by using the successive ionic layer adsorption and reaction (SILAR) method) were conducted. This method attracts interest as it possesses many advantages when compared to other deposition methods. For example, large area depositions could be carried out in any substrates at lower temperatures via inexpensive instruments; moreover, a vacuum chamber is not required, it has an excellent growth rate, and the unique film properties could be controlled. In this work, metal sulfide, metal selenide, metal oxide, and metal telluride were deposited on substrates by using the SILAR method. According to the findings, both thick and thin films could be synthesized under specific conditions during the experiment. Additionally, the results showed that the number of deposition cycles, rinsing times, immersion times, and concentrations of the precursors affected the crystallinities, grain sizes, film thicknesses, surface roughness, and shapes of the obtained films. These films could be used in solar cell applications with high power conversion efficiency due to the appropriate band gap value and high absorption coefficient value.

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“…The estimated Eg Opt = 2.55 eV is in accordance with the reported results. [38,39] A strong relationship between the Eg Opt and the performance of transition metal-based oxide catalysts was early established and reported in the literature. [17,[40][41][42] Genuinely, catalysts made of TMOs with lower optical energy band gap substantially reveal excellent electron mobility which orderly enhances the mobility of oxygenated species (O -, O2 -, O2 2-) in the vicinity of the surface void together with the reducibility, decisive in the catalyst successful advancement.…”

Section: Elemental Chemical Configuration and Oxidation States Analysismentioning

confidence: 99%

Low-Temperature Catalytic Methane Deep Oxidation over Sol-gel derived Mesoporous Hausmannite (Mn3O4) Spherical Particles

Ndouka ndouka,

Kenmoe,

Mache

et al. 2024

Preprint

0

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Herein, Mn3O4 spherical particles (SPs) were synthesized by the sol-gel process, followed by thermal annealing at 400 °C. The sample was analyzed by XRD, FTIR, SEM, SBET, XPS, H2-TPR and UV-vis spectroscopy. XRD and FTIR analysis show that Mn3O4 exhibits a tetragonal spinel structure. SEM and SBET analysis display a porous homogeneous surface made of strongly agglomerated spherical-like grains size with an estimated average particle size of ~35 nm, corresponding to a large specific surface area (SBET) of ~81.5 m2/g. XPS analysis indicated that, Mn3O4 were composed of metallic cations (Mn4+, Mn3+, Mn2+) and oxygen species (O2-, OH- and CO32-). The optical energy band gap energy was ~2.55eV. Moreover, Mn3O4 SPs were successfully tested as catalyst with almost 100% conversion of CH4 to CO2 and H2O at a gas hourly space velocity (GHSV) of 72 000 mL3.g-1h-1. The observed performance can be assigned to the cooperated effects of the smallest spherical-like grain size with mesoporous structure as responsible for the larger SBET, and the available surface-active oxygenated species. The cooperative effect of the good reducibility, the higher ratio of active species (OLat/OAds), as well as Density Functional Theory (DFT) calculations suggested that, CH4 total oxidation over the mesoporous Mn3O4 SPs might follow a two-term process in which both Langmuir-Hinshelwood and Mars-van Krevelen mechanisms are cooperatively involved.

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“…Typical spectrum is displayed in figure 6 and clearly identify the characteristic absorption bands decreasing as the wavelength towards the visible region increase, in line with the literature data. [38,39] The optical bandgap energy was estimated from the obtained absorption spectra using the Tauc law:…”

Section: Elemental Chemical Configuration and Oxidation States Analysismentioning

confidence: 99%

Low-Temperature Catalytic Methane Deep Oxidation over Sol-gel derived Mesoporous Hausmannite (Mn3O4) Spherical Particles

Ndouka ndouka,

Kenmoe,

Mache

et al. 2024

Preprint

0

View full text Add to dashboard Cite

Herein, Mn3O4 spherical particles (SPs) were synthesized by the sol-gel process, followed by thermal annealing at 400 °C. The sample was analyzed by XRD, FTIR, SEM, SBET, XPS, H2-TPR and UV-vis spectroscopy. XRD and FTIR analysis show that Mn3O4 exhibits a tetragonal spinel structure. SEM and SBET analysis display a porous homogeneous surface made of strongly agglomerated spherical-like grains size with an estimated average particle size of ~35 nm, corresponding to a large specific surface area (SBET) of ~81.5 m2/g. XPS analysis indicated that, Mn3O4 were composed of metallic cations (Mn4+, Mn3+, Mn2+) and oxygen species (O2-, OH- and CO32-). The optical energy band gap energy was ~2.55eV. Moreover, Mn3O4 SPs were successfully tested as catalyst with almost 100% conversion of CH4 to CO2 and H2O at a gas hourly space velocity (GHSV) of 72 000 mL3.g-1h-1. The observed performance can be assigned to the cooperated effects of the smallest spherical-like grain size with mesoporous structure as responsible for the larger SBET, and the available surface-active oxygenated species. The cooperative effect of the good reducibility, the higher ratio of active species (OLat/OAds), as well as Density Functional Theory (DFT) calculations suggested that, CH4 total oxidation over the mesoporous Mn3O4 SPs might follow a two-term process in which both Langmuir-Hinshelwood and Mars-van Krevelen mechanisms are cooperatively involved.

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Enhanced electrochemical property of SILAR-deposited Mn3O4 thin films decorated on graphene

Cited by 24 publications

References 29 publications

Recent Advances in the Growth and Characterizations of SILAR-Deposited Thin Films

Recent Advances in the Growth and Characterizations of SILAR-Deposited Thin Films

Low-Temperature Catalytic Methane Deep Oxidation over Sol-gel derived Mesoporous Hausmannite (Mn3O4) Spherical Particles

Low-Temperature Catalytic Methane Deep Oxidation over Sol-gel derived Mesoporous Hausmannite (Mn3O4) Spherical Particles

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