Surface oxygen vacancy induced α-MnO 2 nanofiber for highly efficient ozone elimination

Zhu, Guoxiang; Zhu, Jinguo; Jiang, Wen; Zhang, Zijian; Wang, Jun; Zhu, Yongfa

doi:10.1016/j.apcatb.2017.02.068

Cited by 396 publications

(214 citation statements)

References 47 publications

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“…Clearly, evolution of Mn 2 O 3 and Mn 3 O 4 phases is in line with that of the initial catalyst activity against the Co/Mn molar ratio(Figure 4). As clearly noted previously, indeed, low-valent manganese species favor the O 3 decomposition [2,5,6,39,40]. As further revealed by H 2 -TPR, Raman and XPS results in posterior section, in nature, appropriate Co/Mn molar ratio can enhance the interactions between CoO x and MnO x thereby leading to improved redox properties of MnO x and facilitating the formation of low-valent manganese (Mn 3 + and Mn 2 + ) species on the catalyst surface.…”

supporting

confidence: 62%

“…Mn 2 O 3 !Mn 3 O 4 ) when calcining at elevated temperature so as to tune the O 3 decomposition activity that is sensitive to the content of low-valent manganese species. [6,24,39,40] Figure 5, it is safe to say that the catalyst calcination temperature of 500°C is favorable for reaching a high content of low-valent manganese species, which is essential for high O 3 decomposition activity according to the previous reports. [6,36,41,42]…”

Section: Effect Of Calcination Temperaturementioning

confidence: 88%

“…[17,43] It should be noted that our structured Co-MnO x (0.36)-Al catalyst exhibits markedly improved moisture resistance for O 3 decomposition in comparison with powdered MnO 2 catalysts reported previously. [40] A possible explanation is that entirely open porous structure and thin catalyst layer (~1 μm, Figure S3) of our Co-MnO x (0.36)-Al catalyst show ability to weaken the capillary condensation of water.…”

Section: Effects Of O 3 Concentration Ghsv and Relative Humiditymentioning

confidence: 96%

“…As previously noted, [38] the mixed valency (Mn 2 + , Mn 3 + and Mn 4 + ) is helpful for electron transport, which might be paramount for the improvement of catalyst reactivity for the redox reactions. Notable, the fraction of [6,24,39,40] In short, formation of surface Mn 2 + species together with a high surface content of Mn 2 + and Mn 3 + species accounts for the improved O 3 decomposition activity for the Co-MnO x -Al catalysts. As shown in Figure 11B, O1s XPS spectra can be split into two peaks at BE of 529.8-530.0 eV and 531.1-531.2 eV respectively, being assignable to surface lattice oxygen (denoted as O latt , such as O 2À ) and adsorbed oxygen (denoted as O ads , such as O 2À , O 2 2À or O À ).…”

Section: H 2 -Tprmentioning

confidence: 99%

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High‐Performance Co‐MnO_x Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O₃ Decomposition

et al. 2019

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A highly active and efficient thin-felt Al-fiber-structured Co-MnO x composite oxide catalyst (named Co-MnO x -Al) with unique form factor and high permeability is developed for highthroughput catalytic decomposition of gaseous ozone (O 3 ). Thin-sheet Al-fiber felt (60 μm diameter; 90 vol % voidage) chips underwent a steam-only oxidation and calcination for endogenously growing a 0.7-μm-thick mesoporous layer of γ-Al 2 O 3 nanosheets along with the Al-fiber. Cobalt and manganese were placed onto the ns-γ-Al 2 O 3 /Al-fiber chips by incipient wetness co-impregnation method. The best catalyst is the one with a Co/Mn molar ratio of 0.36 and Co-Mn loading of 5 wt % after calcining at 500°C (named Co-MnO x (0.36)-Al), being able to achieve full O 3 conversion at 25°C for a feed gas containing 1000 � 30 ppm O 3 , using a high gas hourly space velocity of 48000 mL g cat.À 1 h À 1 ; full O 3 conversion is retained in the absence of moisture till the testing end after 720 min; in case with a relative humidity of 50 %, O 3 conversion slides from 88 % of the initial value to a flat of~66 % within 90 min. CoO x modification is paramount for improved formation of Mn 2 + species while leading to the highest fraction of (Mn 2 + + Mn 3 + ) in total (Mn 2 + + Mn 3 + + Mn 4 + ) and more oxygen vacancies on Co-MnO x (0.36)-Al catalyst surface.[a] L.

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supporting

confidence: 62%

Section: Effect Of Calcination Temperaturementioning

confidence: 88%

Section: Effects Of O 3 Concentration Ghsv and Relative Humiditymentioning

confidence: 96%

Section: H 2 -Tprmentioning

confidence: 99%

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High‐Performance Co‐MnO_x Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O₃ Decomposition

et al. 2019

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“…Oxygen vacancies were important parts of ZnO structure because those were the place for ozone to be absorbed and oxygen to be desorbed from catalysts. When ozone molecule was on the surface of catalyst, one oxygen atom from ozone would fill the oxygen vacancies in ZnO and leave the oxygen gas to be released from catalysts [6]. …”

Section: Resultsmentioning

confidence: 99%

Preparation of zinc oxide catalyst with activated carbon support for ozone decomposition

Pradyasti

Azhariyah

Karamah³

et al. 2018

IOP Conf. Ser.: Earth Environ. Sci.

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Abstract. Investigation of catalyst for ozone decomposition was carried out by using zinc oxide (ZnO) catalyst and granular activated carbon (GAC) support. Ozone needs to be decomposed because it is harmful to human and can lead to death. Before GAC was used as a support, GAC was pre-treated using chloride acid (HCl) and sodium hydroxide (NaOH) to remove impurities. ZnO was impregnated onto the surface of GAC by using zinc carbonate (ZnCO3) solution as precursor and then calcined at 300 °C to decompose carbon dioxide (CO2). Size of GAC and loading percentage of ZnO were varied to get the highest catalytic activity. Size of GAC was varied between 18 -100 mesh and loading percentage was between 0 -2%-w. The morphology, composition, and crystal phase were characterized by BET, SEM-EDX, and XRD method. From XRD method, crystal phase of catalyst was changed from ZnCO3 structure to ZnO when calcined with exact temperature. Ozone decomposition was performed at room temperature and atmospheric pressure using fixed bed reactor. ZnO/GAC with smallest size (60 -100 mesh) and highest loading percentage (2%-w) showed the highest activity which the conversion reached 100% for 30 minutes. ZnO/GAC with smallest size and highest loading percentage had the largest surface area and the most active sites to decompose ozone.

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Revealing the Synergy of Cation and Anion Vacancies on Improving Overall Water Splitting Kinetics

Liu

Bui

Jadhav

et al. 2021

Adv Funct Materials

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The exact understanding for each promotional role of cation and anion vacancies in bifunctional water splitting activity will assist in the development of an efficient activation strategy of inert catalysts. Herein, systematic first-principles computations demonstrate that the synergy of anion-oxygen and cation-manganese vacancies (V O and V Mn ) in manganese dioxide (MnO 2 ) nanosheets results in abnormal local lattice distortion and electronic modulation. Such alterations enrich the accessible active centers, increase conductivity, enhance the water dissociation step, and favor intermediate adsorption-desorption, consequently promoting HER and OER kinetics. As proof of concept, robust electrocatalysts, MnO 2 ultrathin nanosheets doped with dual vacancies (DV-MnO 2 ) are obtained via a maturely chemical strategy. Detailed characterizations confirm the cation vacancies-V Mn contribute to enhanced conductivity and anion vacancies-V O enrich the active centers with optimized local electronic configurations, consistent with the simulative predictions. As expected, DV-MnO 2 exhibits exceptional bifunctionality with the strong assistance of synergetic dual vacancies which act as abundant "hot spots" for active multiple intermediates. Leading to a lower cell voltage (1.55 V) in alkali electrolyte is required to reach 10 mA cm −2 for the overall water splitting system. These atomic-level insights on synergetic DV can favor the development of activating strategy from inert electrocatalysts.

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Surface oxygen vacancy induced α-MnO 2 nanofiber for highly efficient ozone elimination

Cited by 396 publications

References 47 publications

High‐Performance Co‐MnO_x Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O₃ Decomposition

High‐Performance Co‐MnO_x Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O₃ Decomposition

Preparation of zinc oxide catalyst with activated carbon support for ozone decomposition

Revealing the Synergy of Cation and Anion Vacancies on Improving Overall Water Splitting Kinetics

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Surface oxygen vacancy induced α-MnO 2 nanofiber for highly efficient ozone elimination

Cited by 396 publications

References 47 publications

High‐Performance Co‐MnOx Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O3 Decomposition

High‐Performance Co‐MnOx Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O3 Decomposition

Preparation of zinc oxide catalyst with activated carbon support for ozone decomposition

Revealing the Synergy of Cation and Anion Vacancies on Improving Overall Water Splitting Kinetics

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Product

Resources

About

High‐Performance Co‐MnO_x Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O₃ Decomposition

High‐Performance Co‐MnO_x Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O₃ Decomposition