Influence of Oxygen Vacancy in Mangan-based Catalyst on Phenol Removal Via Catalytic Ozonation
Liquan Xia,
Guifeng Chen,
Wenbo Li,
Minglong Gao,
Jiaxin Zhao
Issue:
Volume 5, Issue 4, December 2020
Pages:
48-56
Received:
16 October 2020
Accepted:
2 November 2020
Published:
27 November 2020
Abstract: In order to improve the performance of the catalyst applied in ozonation, this work show the hydrothermal synthesis routine to prepare MnO2 with different oxygen vacancy content. The α-MnO2 was aminated and further processed with doped graphene oxide (GO) to obtain high oxygen vacancy content α-MnO2-NH2-GO, which was subsequently used for catalyzing ozonation phenol degradate. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Brunner-Emmet-Teller (BET), H2-temperature-programmed reduction (H2-TPR), scanning electron microscopy (SEM), etc. Characterization and experimental results showed that the oxygen vacancy content has an important effect on the catalytic performance of the catalyst, MnO2 with low average oxidation state showed better catalytic ozonation performance. The coexistence of Mn3+ and Mn4+ have great significant role for the continuous generation of free radicals and the restoration of oxygen vacancies. The doping of GO can increase the electron transfer rate, and improve the catalytic performance. The catalytic performance of α-MnO2-NH2-GO is better than α-MnO2, phenol removal rate can achieve more than 99% within 30 min, and superoxide radicals can be determined by different free radical trapping agents. The results of main active oxygen and reaction kinetics research showed that the degradation of phenol is a first-order reaction whether α-MnO2-NH2-GO or α-MnO2 is used as a catalyst.
Abstract: In order to improve the performance of the catalyst applied in ozonation, this work show the hydrothermal synthesis routine to prepare MnO2 with different oxygen vacancy content. The α-MnO2 was aminated and further processed with doped graphene oxide (GO) to obtain high oxygen vacancy content α-MnO2-NH2-GO, which was subsequently used for catalyzin...
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Lanthanum-Doped Ceria Nanocomposite: A Highly Stable Monolithic Catalyst for Direct Synthesis of Dimethyl Carbonate
Wei Chen,
Zhongbin Ye,
Yue Li,
Nanjun Lai,
Zhaohua Song,
Yongdong Chen
Issue:
Volume 5, Issue 4, December 2020
Pages:
57-66
Received:
1 December 2020
Accepted:
22 December 2020
Published:
31 December 2020
Abstract: That dimethyl carbonate is directly synthesized from methanol and carbon dioxide is an effective and environmental approach to solve the greenhouse effect. For the sake of solving the problems of low DMC productivity and poor catalysts stability in presence of the formed water. Here we design and prepare a serial of spherical La-doped ceria nanoparticles (Ce1-xLaxOδ nanocomposites, x=0.00, 0.05, 0.10, 0.15, and 0.20) via a co-precipitation method. These Ce1-xLaxOδ composites are ground into slurry by ball milled and then coated on cordierite honeycomb ceramics to obtain Ce1-xLaxOδ monolithic catalysts. These Ce1-xLaxOδ composites are characterized extensively by TEM, XRD, Raman spectroscopy, N2 adsorption-desorption isotherms, H2-TPR and XPS. The characterization results show that the Ce1-xLaxOδ composites nanoparticles possesses richer surface oxygen vacancies, higher BET surface area and smaller particle size than that of pure CeO2 nanoparticle. Besides, catalytic activity test shows these Ce1-xLaxOδ monolithic catalysts exhibit better catalytic performance than that of pure CeO2 nanoparticles. Among them, Ce0.95La0.05Oδ monolithic catalyst exhibits the highest CH3OH conversion and DMC yield, which is in good line with the oxygen vacancy content measured by XPS. Finally, the Ce0.95La0.05Oδ monolithic catalyst also shows an excellent durability of more than 100 hours, which is mainly due to the doping effect of lanthanum into the ceria oxides tailoring the structure and surface properties of the catalyst.
Abstract: That dimethyl carbonate is directly synthesized from methanol and carbon dioxide is an effective and environmental approach to solve the greenhouse effect. For the sake of solving the problems of low DMC productivity and poor catalysts stability in presence of the formed water. Here we design and prepare a serial of spherical La-doped ceria nanopar...
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