JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Jiafei Su,Cuilian Cheng,Yaping Guo,He Xu,Qinfei Ke
Cryptomelane-type octahedral molecular sieve (OMS-2) catalysts are currently attracting tremendous attention due to their low-cost and remarkable thermo-catalytic activity. However, it is still difficult for OMS-2 catalysts to completely degrade formaldehyde at relatively low or even ambient temperature. In this work, OMS-2 catalysts with different ratios of length to diameter were prepared and the OMS-2-s with the minim ratio of length to diameter (1–3) exhibited the best catalytic performance than the other samples. Then, the optimized OMS-2-s nanorods were loaded on the SiO 2 nanofibers via a simultaneous electrospining-spray strategy. The evaluation for the dynamic catalytic activities of the samples showed that, the T 50 (HCHO conversion reached to 50%) for the OMS-2/SiO 2 nanofibrous membranes was decreased by 24 °C than the OMS-2-s nanorods. Furthermore, in the static experiment of HCHO decomposition, the composite membrane could achieve a catalytic efficiency of 52.3% at 25 °C, much higher than that of the OMS-2-s nanorods (45.9%). This work offers a new strategy to improve the catalytic efficiency of OMS-2 by controlling the morphology and loading of OMS-2 nanorods, and also designs a kind of advanced nano OMS-2-based nanofibrous membranes with hierarchical nanostructures for the highly efficient formaldehyde elimination during the practical application.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Shandi Zhong,Cai Xu,Quanfu Long,Hang Zhou,Jianhai Yang,Jia Guo,Xiaozhong Wang,Liyan Dai
Using O 2 as an oxidant, developing a non-noble metal catalyst for the selective catalytic C–H bond oxidation of p-chlorotoluene is desirable and challenging. In this work, a series of Co, Cr co-doped OMS-2 (Octahedral Molecular Sieve-2) catalysts were prepared by a conventional refluxing method. It was found that the incorporation of Co and Cr improved the catalytic activity for the selective oxidation of p-chlorotoluene to p-chlorobenzaldehyde. Among these catalysts, CoCr/OMS-2 (Co: Cr = 1: 1, mass ratio), the best catalyst, shows that the conversion and the selectivity of p-chlorobenzaldehyde is 94.8 % and 94.3 %, respectively. The enhanced catalytic activity was due to the larger specific surface area and even dispersion of active components. The characterization results also disclosed that the co-doping of Co and Cr increased the oxygen vacancy and enhanced the ability to activate the surface lattice oxygen. Additionally, density functional theory calculations demonstrated that co-doping of Co and Cr promoted the adsorption of p-chlorotoluene and O 2 , and decreased the energy barrier of rate-determining step (the conversion of p-chlorobenzyl alcohol to p-chlorobenzaldehyde). Besides, when H 2 O was added to the reaction system as the second solvent, the activation and dissociation of O 2 , and the formation of p-chlorobenzaldehyde were facilitated, in agreement with the experimental results. This work demonstrated the promotional effect of Co, Cr co-doped into OMS-2 catalyst and the role of H 2 O for the selective oxidation of p-chlorotoluene.
研究领域:
催化化学
·
材料科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2015
·Vol. 39
·期 8
·6395-6403
·
IF 3.086
Mingyu Wei,Yang Ruan,Shilu Luo,Xiaoxia Li,Aihua Xu,Ping Zhang
A magnetically recyclable nanocomposite, manganese oxide octahedral molecular sieve (OMS-2) coated Fe3O4 nanoparticles, was prepared using a facile solvent-free process with manganese salts and Fe3O4 at a low temperature. XRD, SEM, TEM, FT-IR, XPS and N2 adsorption–desorption isotherm analysis showed that in the core–shell nanocomposite, OMS-2 was homogeneously distributed on the Fe3O4 surface with similar structures to that of pure OMS-2 but a much higher surface area of 251 m2 g−1. The catalyst exhibited excellent activity toward the degradation of Acid Orange 7 (AO7), Reactive Brilliant Blue KN-R, Reactive Brilliant Red X-3B, methylene blue, methyl orange, and rhodamine B in the presence of peroxymonosulfate (PMS), with nearly complete decolorization within 15 min. The catalyst could also be easily recovered with the assistance of an external magnetic field, and could be reused for ten successive cycles without any change of structure. The loss of Mn ions in solution was lower than 0.05 mg L−1 and no Fe ions were detected. The effect of several parameters, including the OMS-2 content in the nanocomposites, the concentration of AO7, PMS and the catalyst, and solution pH, on the degradation efficiency was also discussed.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2019
·Vol. 33
·期 6
·e4815
·
IF 3.259
Qiancheng Zou,Yi Wei,Shuai Wang,Jinyan Xie,Aihua Xu,Xiaoxia Li
The development of green and efficient catalysts for peroxymonosulfate (PMS) activation and organic pollutants degradation has received widespread attention. In this study, the hybrid CaCO 3 /OMS-2 catalysts were prepared by a simple precipitation approach and characterized by X-ray powder diffraction, N 2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and cyclic voltammetry. It was found that deposition of CaCO 3 on OMS-2 surface can weaken the Mn-O bond by formation of Ca-O-Mn bond. The interactions between CaCO 3 and OMS-2 significantly enhanced Acid Orange 7 degradation in the presence of PMS with a pseudo-first-order kinetic constant of 0.21 min −1 , which was much higher than those of OMS-2 (0.026 min −1 ) and CaCO 3 (0.021 min −1 ). The CaCO 3 /OMS catalysts were also much more efficient than other reported OMS-2 hybrid catalysts, and could be performed over a wide solution pH and for other organic dyes degradation. Sulfate and hydroxyl radicals were formed from the oxidation of low valent manganese species by PMS as the active species in the system. This study can provide a simple method for the design of efficient manganese-based hybrids for wastewater remediation via PMS activation.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
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