Ammonium-treated birnessite-type MnO2 to increase oxygen vacancies and surface acidity for stably decomposing ozone in humid condition

Cao, Ranran; Zhang, Pengyi; Liu, Yang; Zheng, Xianming

doi:10.1016/j.apsusc.2019.143607

Cited by 71 publications

(25 citation statements)

References 59 publications

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“…9b). In addition, the formation of valence band holes accompanying the photocatalytic self-reduction and the generation of Mn(III) can oxidise water or dissolved organic matter (Chan et al, 2018). In the Raman spectra of oxygen evolution reaction (OER), Mn(III) induced local strain on the oxide sublattice is also observed , which further proves the one-electron transfer mechanism (Chan et al, 2018).…”

Section: Photocatalytic Self-reduction Of Natural Mn Oxidesmentioning

confidence: 89%

“…Such a configuration can remarkably decrease the bandgap of O-defected birnessite compared with the non-vacancy one. In contrast, O vacancies also commonly exist in other metal oxides and work as active sites in reactions (Wang et al , 2017; Cao et al , 2019). In Nature, multiple surfaces may be exposed and therefore perform different levels of photoactivity.…”

Section: Electronic Structure Of Mn Oxidesmentioning

confidence: 99%

“…One electron in the O 2p orbital can transfer to the empty e g orbital of Mn(IV) under sunlight irradiation to form intermediate Mn(III) (Luther, 2005;Sakai et al, 2005). Mn(III) is in a tetragonally distorted rather than in octahedral geometry, resulting in higher kinetic lability (ligand exchange) and reactivity (Marafatto et al, 2015;Chan et al, 2018). The e g of Mn(III) therefore are prone to accept the photo-electron and thus the Mn(III) is further reduced to Mn(II) (Luther, 2005).…”

Section: Photocatalytic Self-reduction Of Natural Mn Oxidesmentioning

confidence: 99%

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The photogeochemical cycle of Mn oxides on the Earth's surface

Liu

et al. 2021

MinMag

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Manganese (Mn) oxides have been prevalent on Earth since before the Great Oxidation Event and the Mn cycle is one of the most important biogeochemical processes on the Earth's surface. In sunlit natural environments, the photochemistry of Mn oxides has been discovered to enable solar energy harvesting and conversion in both geological and biological systems. One of the most widespread Mn oxides is birnessite, which is a semiconducting layered mineral that actively drives Mn photochemical cycling in Nature. The oxygen-evolving centre in biological photosystem II (PSII) is also a Mn-cluster of Mn4CaO5, which transforms into a birnessite-like structure during the photocatalytic oxygen evolution process. This phenomenon draws the potential parallel of Mn-functioned photoreactions between the organic and inorganic world. The Mn photoredox cycling involves both the photo-oxidation of Mn(II) and the photoreductive dissolution of Mn(IV/III) oxides. In Nature, the occurrence of Mn(IV/III) photoreduction is usually accompanied with the oxidative degradation of natural organics. For Mn(II) oxidation into Mn oxides, mechanisms of biological catalysis mediated by microorganisms (such as Pseudomonas putida and Bacillus species) and abiotic photoreactions by semiconducting minerals or reactive oxygen species have both been proposed. In particular, anaerobic Mn(II) photo-oxidation processes have been demonstrated experimentally, which shed light on Mn oxide emergence before atmospheric oxygenation on Earth. This review provides a comprehensive and up-to-date elaboration of Mn oxide photoredox cycling in Nature, and gives brand-new insight into the photochemical properties of semiconducting Mn oxides widespread on the Earth's surface.

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Section: Photocatalytic Self-reduction Of Natural Mn Oxidesmentioning

confidence: 89%

Section: Electronic Structure Of Mn Oxidesmentioning

confidence: 99%

Section: Photocatalytic Self-reduction Of Natural Mn Oxidesmentioning

confidence: 99%

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The photogeochemical cycle of Mn oxides on the Earth's surface

Liu

et al. 2021

MinMag

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“…A narrower band can be observed at 1540 cm −1 , which can be assigned to the formation of pyridinium ions resulting from pyridine protonation on Brønsted acid sites. The interaction of pyridine with Ce 0.01 Mn-AT gave rise to a set of several bands: (i) two bands at 1540 and 1635 cm −1 , associated with pyridinium ions resulting from pyridine protonation on Brønsted acid sites; (ii) two bands at 1450 and 1610 cm −1 , attributed to pyridine coordinated with Lewis acid sites; and (iii) overlapping bands of pyridine on Lewis and Brønsted acid sites at 1487 cm −1 [22,[30][31][32][33]. Moreover, the band at 1573 cm −1 can be attributed to the pyridine physisorption (P) [20], while the band at 1471 cm −1 could have resulted from the interaction between the adsorbed pyridine and manganese oxides [34].…”

Section: Main Physicochemical Characteristics Of the Fresh Materialsmentioning

confidence: 99%

Post-Plasma Catalysis for Trichloroethylene Abatement with Ce-Doped Birnessite Downstream DC Corona Discharge Reactor

Abdallah

Giraudon²,

Bitar

et al. 2021

Catalysts

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Trichloroethylene (TCE) removal was investigated in a post-plasma catalysis (PPC) configuration in nearly dry air (RH = 0.7%) and moist air (RH = 15%), using, for non-thermal plasma (NTP), a 10-pin-to-plate negative DC corona discharge and, for PPC, Ce0.01Mn as a catalyst, calcined at 400 °C (Ce0.01Mn-400) or treated with nitric acid (Ce0.01Mn-AT). One of the key points was to take advantage of the ozone emitted from NTP as a potential source of active oxygen species for further oxidation, at a very low temperature (100 °C), of untreated TCE and of potential gaseous hazardous by-products from the NTP. The plasma-assisted Ce0.01Mn-AT catalyst presented the best CO2 yield in dry air, with minimization of the formation of gaseous chlorinated by-products. This result was attributed to the high level of oxygen vacancies with a higher amount of Mn3+, improved specific surface area and strong surface acidity. These features also allow the promotion of ozone decomposition efficiency. Both catalysts exhibited good stability towards chlorine. Ce0.01Mn-AT tested in moist air (RH = 15%) showed good stability as a function of time, indicating good water tolerance also.

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“…Many strategies, such as NH 4 + , [20] K + [21] and nitric acid [22] governance, gas assistance, [23] and element doping, [19,[24][25][26] were employed for introducing oxygen defects. For example, Fang et al [27] synthesized δ-MnO 2 nanosheets by hydrothermal method and regulated oxygen defects by heat treatment.…”

Section: Introductionmentioning

confidence: 99%

Oxygen Defect Engineering of β‐MnO₂ Catalysts via Phase Transformation for Selective Catalytic Reduction of NO

Yang¹,

Peng²,

Lan

et al. 2021

Small

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The catalysts for low‐temperature selective catalytic reduction of NO with NH3 (NH3‐SCR) are highly desired due to the large demand in industrial furnaces. The characteristic of low‐temperature requires the catalyst with rich active sites especially the redox sites. Herein, the authors obtain oxygen defect‐rich β‐MnO2 from a crystal phase transformation process during air calcination, by which the as‐prepared γ‐MnO2 nanosheet and nanorod can be conformally transformed into the corresponding β‐MnO2. Simultaneously, this transformation accompanies oxygen defects modulation resulted from lattice rearrangement. The most active β‐MnO2 nanosheet with plentiful oxygen defects shows a high efficiency of > 90% NO conversion in an extremely wide operation window of ≈120–350 °C. The detailed characterizations and density functional theory (DFT) calculations reveal that the introduction of oxygen defects enhances the adsorption properties for reactants and decreases the energy barriers of *NH2 formation more than 0.3 eV (≈0.32–0.37 eV), which contributes to a high efficiency of low‐temperature SCR activity. The authors finding provides a feasible approach to achieve the oxygen defect engineering and gains insight into manganese‐based catalysts for low‐temperature NO removal or pre‐oxidation.

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Ammonium-treated birnessite-type MnO2 to increase oxygen vacancies and surface acidity for stably decomposing ozone in humid condition

Cited by 71 publications

References 59 publications

The photogeochemical cycle of Mn oxides on the Earth's surface

The photogeochemical cycle of Mn oxides on the Earth's surface

Post-Plasma Catalysis for Trichloroethylene Abatement with Ce-Doped Birnessite Downstream DC Corona Discharge Reactor

Oxygen Defect Engineering of β‐MnO₂ Catalysts via Phase Transformation for Selective Catalytic Reduction of NO

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Ammonium-treated birnessite-type MnO2 to increase oxygen vacancies and surface acidity for stably decomposing ozone in humid condition

Cited by 71 publications

References 59 publications

The photogeochemical cycle of Mn oxides on the Earth's surface

The photogeochemical cycle of Mn oxides on the Earth's surface

Post-Plasma Catalysis for Trichloroethylene Abatement with Ce-Doped Birnessite Downstream DC Corona Discharge Reactor

Oxygen Defect Engineering of β‐MnO2 Catalysts via Phase Transformation for Selective Catalytic Reduction of NO

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Oxygen Defect Engineering of β‐MnO₂ Catalysts via Phase Transformation for Selective Catalytic Reduction of NO