Catalytic oxidation of toluene over MnO2 catalysts with different Mn (II) precursors and the study of reaction pathway

Lyu, Yue; Li, Caiting; Du, Xueyu; Zhu, Youcai; Zhang, Yindi; Li, Shanhong

doi:10.1016/j.fuel.2019.116610

Cited by 100 publications

(36 citation statements)

References 44 publications

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“…Also, the lattice parameters a, b, and c of Co-α-MnO 2 become greater compared with that of α-MnO 2 (as shown in Table 1), which show a distortion in the lattice cell. The increased relative intensity of α-MnO 2 diffraction peak after Co doping also indicates the existence of lattice defects, which might promote the migration of adsorbed oxygen to decompose and transform organic matter and finally affected the catalytic performance of the catalyst [34,35]. Therefore, Co-α-MnO 2 has better catalytic ozonation of phenol than α-MnO 2 .…”

Section: Crystal Phasementioning

confidence: 99%

“…When introduced into an aqueous solution, H 2 O molecules will be strongly adsorbed on the surface of catalyst. The adsorbed H 2 O molecules will always dissociate into OHand H + [34] and form the surface hydroxyl group with the surface cation and oxygen anion respectively. The released HO 3 • will further decompose and release O 2 and produce •OH.…”

Section: Analysis Of the Catalytic Mechanismmentioning

confidence: 99%

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Phenol Removal Performance and Mechanism Using Catalytic Ozonation with the Catalyst of Cobalt-doped α-MnO2

Zhang

Dong

Han

et al. 2022

Environmental Engineering Research

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In this paper, Cobalt-doped α-MnO2 (i.e., Co-α-MnO2) were synthesized through hydrothermal method. Phenol was employed as targeted pollutants to investigate the catalytic ozonation performance of Co-α-MnO2. Results showed that Co-α-MnO2 significantly improved the phenol removal increased to 97.47 % after 40 min, which was 16.46 %, 38.92 % higher than that of α-MnO2 catalytic ozonation and single ozonation without catalyst. Additionally, the physicochemical properties of α-MnO2 and Co-α-MnO2 were analyzed using technologies such as XRD, TEM, BET and XPS. Compared to α-MnO2, Co-α-MnO2 has larger specific surface area (79.496 m 2 /g) and pore volume (0.0396 cm 3 /g), higher Mn 3+ relative content (41.16 %) and adsorbed oxygen content (18.99 %). Also, the oxygen vacancy content, lattice defect content and surface hydroxyl content of Co-α-MnO2 are higher than that of α-MnO2, which could result in higher catalytic oxidation performance of Co-α-MnO2. The influence of masking agent showed that surface hydroxyl group, •OH and •O 2were involved in the catalytic ozonation of phenol. This study could help recognize the role of surface hydroxyl groups and active free radicals and demonstrate the contribution of reactive oxygen species on phenol removal in Co-α-MnO2 systems.

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Section: Crystal Phasementioning

confidence: 99%

Section: Analysis Of the Catalytic Mechanismmentioning

confidence: 99%

Phenol Removal Performance and Mechanism Using Catalytic Ozonation with the Catalyst of Cobalt-doped α-MnO2

Zhang

Dong

Han

et al. 2022

Environmental Engineering Research

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“…However, almost no change is found for the Ag-decorated catalyst sample (23.0 m 2 ·g –1 ). It is well known that the catalytic materials with higher specific surface areas would provide more catalytic active centers and can significantly enhance the catalytic activity. , Herein, the surface structural properties and catalytic data of various catalysts including Pt-modulated MnCu binary nanosheet-like catalysts and Ag-decorated MnCu catalysts, which were comparable to that of commercial noble metal catalysts (Pt-Pd/Al 2 O 3 ), are presented in Tables and . It is evident that the addition of a small amount of Pt (less than 0.5 wt %) into MnCu catalysts did not increase the SSA but significantly improve their catalytic capacity for toluene combustion via the SPF technique in this study (Table ).…”

Section: Results and Discussionmentioning

confidence: 99%

Pt-Modulated CuMnO_x Nanosheets as Catalysts for Toluene Oxidation

Wahab

et al. 2021

ACS Appl. Nano Mater.

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Controllable ternary Pt–Cu–Mn lamellar oxides with different amounts of Pt were synthesized using a facile and expeditious self-propagating flaming technique for catalytic oxidation of toluene. The surface structure, composition, and structure–performance relationship were investigated by combining X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area, scanning electron microscopy (SEM), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The catalytic performance of the as-produced catalysts toward the catalytic oxidation of toluene was investigated. Among the catalysts, the 0.5Pt-MnCu catalyst has shown 90% toluene removal at 228 °C with excellent cyclic stability, which is a significant achievement for MnCu binary nanosheet-like catalysts containing low amounts of Pt (0.5 wt %). This study has also inferred the degradation activity of modulated MnCu composite catalysts, which greatly hinges on the doping level of Pt. The lattice oxygen species are dominating according to the Mn–O bond strength, local environment, and reducibility. Moreover, Pt can increase the covalency of surface metal–oxygen bonds and electron affinity of surface metal-coordinated oxygen centers, thereby expediting the adsorption/activation of the gaseous oxygen molecules on oxide surfaces, which can step up the lattice oxygen as well as oxygen vacancy-involved reactions to invoke the Mars–van Krevelen and Langmuir–Hinshelwood mechanisms for boosting the overall toluene oxidation performance of PtCuMnO x catalytic materials. Based on the obtained results, this study proposes a vital insight into manipulating the nanoscale catalytic functions, which could also promise pivotal potential toward engineering the state-of-the-art transition-metal nanostructure for environmental catalysis.

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“…This shows that Co doping enters the MnO 2 skeleton structure by replacing Mn or is embedded in the pore structure of the catalyst tunnel, rather than existing on the catalyst surface in the form of cobalt oxide with similar ionic radius to CO 2+ and Mn 2+ . However, the Co doping on α-MnO 2 would cause the deformation of α-MnO 2 lattice, which make the grain diameter decrease and the parameters a, b and c increase (as showed in Table 2) and show a distortion in the lattice cell, thus further promotes the migration of adsorbed oxygen to decompose and oxidize organic matter (Yu et al, 2020;Peña et al, 2004).…”

Section: Crystal Phasementioning

confidence: 99%

“…Metal oxides (e.g., MnO 2 , Fe oxides, CoFe 2 O 4 , TiO 2 ) have been widely used as the catalysts in heterogeneous catalytic ozonation (Du et al, 2020;Oliveira et al, 2019;Yang et al, 2014). Among these metal oxides, MnO 2 showed the excellent catalytic performance on benzene series degradation due to its strong redox coples of Mn 2+ /Mn 3+ and Mn 3+ /Mn 4+ on the surface of catalysts, diverse and crystallographic structure (Niu et al, 2019;Zhang et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Catalytic Ozonation for Phenol Removal over Cobalt-doped α-MnO2 Catalyst: Performance and Mechanism

Zhang

Dong

Han

et al. 2022

Preprint

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In this paper, Cobalt-doped α-MnO2 (i.e., Co-α-MnO2) were synthesized through hydrothermal method. Phenol was employed as targeted pollutants to investigate the catalytic ozonation performance of Co-α-MnO2 in terms of catalytic ability and mechanism. Results showed that that Co doped on α-MnO2 significantly improved the phenol removal increased to 97.47 % after 40 min, which was 16.46 %, 38.92 % higher than that of α-MnO2 catalytic ozonation and single ozonation without catalyst. In order to investigate the effect of Co doping on the physicochemical properties of the catalysts, the synthesized α-MnO2 and Co-α-MnO2 (2% Co/Mn doping ratio) catalysts were characterized by XRD, TEM, BET and XPS techniques, including the phase, morphology, structural properties and dispersity of the surface active species. The larger specific surface area and pore volume, more crystal defect and oxygen vacancy, higher relative content of Mn3+ and adsorbed oxygen (Oads) as well as surface hydroxyl were obtained after Co doping on α-MnO2, which could result in higher catalytic oxidation performance of Co-α-MnO2. The influence of masking agent showed that surface hydroxyl group and active free radicals (•OH and •O2-) were involved in the catalytic ozonation of phenol. This study could help recognize the role of surface hydroxyl groups and active free radicals and demonstrate the contribution of reactive oxygen species (ROS) on phenol removal in Co-α-MnO2 systems.

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Catalytic oxidation of toluene over MnO2 catalysts with different Mn (II) precursors and the study of reaction pathway

Cited by 100 publications

References 44 publications

Phenol Removal Performance and Mechanism Using Catalytic Ozonation with the Catalyst of Cobalt-doped α-MnO2

Phenol Removal Performance and Mechanism Using Catalytic Ozonation with the Catalyst of Cobalt-doped α-MnO2

Pt-Modulated CuMnO_x Nanosheets as Catalysts for Toluene Oxidation

Catalytic Ozonation for Phenol Removal over Cobalt-doped α-MnO2 Catalyst: Performance and Mechanism

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Catalytic oxidation of toluene over MnO2 catalysts with different Mn (II) precursors and the study of reaction pathway

Cited by 100 publications

References 44 publications

Phenol Removal Performance and Mechanism Using Catalytic Ozonation with the Catalyst of Cobalt-doped α-MnO2

Phenol Removal Performance and Mechanism Using Catalytic Ozonation with the Catalyst of Cobalt-doped α-MnO2

Pt-Modulated CuMnOx Nanosheets as Catalysts for Toluene Oxidation

Catalytic Ozonation for Phenol Removal over Cobalt-doped α-MnO2 Catalyst: Performance and Mechanism

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Pt-Modulated CuMnO_x Nanosheets as Catalysts for Toluene Oxidation