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Li, Chengbin,Li, Zhenghua,Oh, Hwa Yong,Hong, Gyong Hee,Park, Jin Seo,Kim, Ji Man Elsevier 2018 CATALYSIS TODAY - Vol.307 No.-
<P><B>Abstract</B></P> <P>Highly ordered mesoporous Cu-Mn-Ce ternary metal oxide materials with various Cu/Mn molar ratios were successfully synthesized by using a nano-casting method from a mesoporous silica template with a cubic <I>Ia</I>3<I>d</I> mesostructure. The ternary metal oxide materials were characterized by X-ray diffraction (XRD), N<SUB>2</SUB>-sorption, electron microscopy, Raman spectroscopy, H<SUB>2</SUB>-temperature programmed reduction and CO-temperature programmed desorption. The XRD results indicated that the materials did not show any diffraction peaks corresponding to copper and manganese oxides, ensuring the formation of Cu<I> <SUB>x</SUB> </I>Mn<SUB>0.2-<I>x</I> </SUB>Ce<SUB>0.8</SUB>O<SUB>2</SUB> (<I>x</I> =0–0.2). The WGS activity of the ternary metal oxide catalysts increased as the molar ratios of Cu/Mn increased. Among the catalysts, the mesoporous Cu<SUB>0.18</SUB>Mn<SUB>0.02</SUB>Ce<SUB>0.8</SUB>O<SUB>2</SUB> catalyst exhibited the best catalytic activity in low temperature range with zero methane yield. Moreover, this catalyst showed excellent catalytic stability during the reaction. The observed enhancement in the WGS performances were attributed to high surface area, uniform crystalline framework with increased structural defect, highly dispersed copper and manganese within the ceria lattice or on the surface, and strong metal support interaction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ordered mesoporous Cu-Mn-Ce ternary metal oxide catalyst showed an excellent WGS reaction performances. </LI> <LI> Copper and manganese, incorporated within the CeO<SUB>2</SUB> lattice, enhanced the activity. </LI> <LI> Mesoporous ternary metal oxides exhibited good nanostructural and catalytic stabilities. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Ordered Mesoporous Cu—Co—CeO<sub>2</sub> Catalyst for Water-Gas Shift Reaction at High Temperature
Li, Chengbin,Li, Zhenghua,Park, Su Bin,Hong, GyoungHee,Park, Jin Seo,Oh, Hwa Yong,Kim, Ji Man American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.11
<P>Highly ordered mesoporous Cu-Co-CeO2 composite catalysts with different Cu/Co ratios were synthesized via a nano-replication method using a mesoporous silica template with cubic laid mesostructure, and the ternary oxide catalysts, thus obtained, were used for a water-gas shift reaction. Combined characterization results, using X-ray diffraction, electron microscopy, N-2 adsorption, and temperature-programmed reduction analysis techniques, reveal that the incorporation of copper and cobalt into the ceria lattice not only promotes the formation of structure defects, but also increases the redox properties. Furthermore, some CoOx, clusters, formed on the catalysts surface, which enhanced the catalytic activity at high temperature. Among the series of composite catalysts, the Cu0.1Co0.1Ce0.8O2 catalyst showed the highest catalytic performance with a zero methane yield.</P>
Li, Chengbin,Oh, Hwa-Yong,Cho, Hye-Jin,Kumarsrininasan, Sivaranjani,Choi, Jong-Ha,Li, Zhenghua,Hong, Gyoung-Hee,Park, Su-Bin,Kim, Ji Man American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11
<P>Binary oxide catalyst (Cu0.15Co2.84O4) supported on mesoporous CeO2 has been prepared by an incipient wetness impregnation method. The produced catalysts with different loading of binary oxide (0-30 wt%) have been thoroughly characterized and applied for a water-gas shift (WGS) reaction. The characterization results indicate that the binary oxide catalysts are highly dispersed on the mesoporous CeO2 support without significant loss of mesostructural properties, even though the catalyst loading reaches 30 wt%. The highest catalytic activity towards WGS reaction has been achieved from the 30 wt% Cu0.15Co2.84O4/CeO2 catalyst, showing 100% CO conversion and very low methane yield (nearly zero%) at relatively low temperature (similar to 300 degrees C). The present Cu0.15Co2.84O4/CeO2 catalyst can be recycled more than three times with loss of the activity. Metallic cobalt species are formed during the reaction, whose structural properties are maintained under the repeated WGS reaction conditions. Excellent catalytic activity and durability originate from the highly dispersed binary oxides on the pore surface of mesoporous CeO2, which is probably due to the strong metal-support interaction.</P>
Gyoung Hee Hong,Zhengyang Li,박진서,Zhenghua Li,Ki Yeong Kim,Chengbin Li,이정호,Mingshi Jin,Galen D. Stucky,Ji Man Kim 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.107 No.-
Highly ordered mesoporous molybdenum dioxide (meso-MoO2) was successfully synthesized by a nanoreplicationmethod using a mesoporous silica template with 3D cubic Ia3d mesostructure. Structuralanalyses using X-ray diffraction, N2 sorption, and electron microscopy indicated that the meso-MoO2material exhibited high surface area (106 m2/g), large pore volume (0.66 cm3/g), and well-defined mesopores. Under the optimized reaction conditions, the meso-MoO2 catalyst showed excellent catalytic performancesfor the acetalization of glycerol with acetone (95.8% of glycerol conversion, and 97.8% ofsolketal selectivity) at 20 C, due to its high surface area with large number of acid sites. During recycling,the meso-MoO2 catalyst exhibited a slight decrease in activity; and after a simple regeneration at 350 C,the catalytic performances could be completely recovered. More importantly, a partial hydrophobic treatmentof the meso-MoO2 catalyst dramatically enhanced the water-tolerance during the catalytic reaction.
Li Xianghua,Ye Quanyi,Chong Yuhua,Zhou Zhenghua,Yang Chun 한국광학회 2014 Current Optics and Photonics Vol.18 No.3
This paper presents a new method for measuring the half-wave voltage Vπ of an electro-optic phase modulator based on a phase-modulated photonic link with interferometric demodulation. By using this method, the Vπ can be obtained with the RF voltage amplitude input required to achieve 1-dB gain compression of link and the differential delay of a Mach-Zehnder interferometer. We measure the Vπ of a commercial phase modulator by using the presented method and the carrier/the first sideband intensity ratio method. Furthermore, we compare the two measurements with the typical value provided by the manufacturer. The experiment shows that this novel measurement method is feasible, straightforward, and accurate.
Expression Profile of Neuro-Endocrine-Immune Network in Rats with Vascular Endothelial Dysfunction
Li, Lujin,Jia, Zhenghua,Xu, Ling,Wu, Yiling,Zheng, Qingshan The Korean Society of Pharmacology 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.2
This study was to determine the correlation between endothelial function and neuro-endocrine-immune (NEI) network through observing the changes of NEI network under the different endothelial dysfunction models. Three endothelial dysfunction models were established in male Wistar rats after exposure to homocysteine (Hcy), high fat diet (HFD) and Hcy+HFD. The results showed that there was endothelial dysfunction in all three models with varying degrees. However, the expression of NEI network was totally different. Interestingly, treatment with simvastatin was able to improve vascular endothelial function and restored the imbalance of the NEI network, observed in the Hcy+HFD group. The results indicated that NEI network may have a strong association with endothelial function, and this relationship can be used to distinguish different risk factors and evaluate drug effects.
Dynamic Range Improvement of IM-DD Optical Link using Dual-Wavelength Dual-Parallel Modulation
Li Xianghua,Zhou Zhenghua,Chong Yuhua,Yang Chun 한국광학회 2014 Current Optics and Photonics Vol.18 No.4
In this paper, we present an incoherent dual-parallel modulation linearized optical link employing two different optical wavelengths. Comparing with previous dual-parallel modulation, this linearization method prevents the recreation of distortion products and can be readily implemented. Furthermore, a dual-wavelength dual-parallel modulation linearized optical link constructed with the commercially available devices is experimentally demonstrated with a spurious-free dynamic range of 122.5 dB.Hz4/5. More than 25 dB suppression of the intermodulation distortion, 15.6 dB improvement of spurious-free dynamic range and 1.5 dB improvement of compression dynamic range are achieved after linearization.
Huijie Li,Fanming Meng,Jinfeng Gong,Zhenghua Fan,Rui Qin 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.4
CeO2 nanospheres with the core–shell nanostructure have been successfully synthesized by a template-free hydrothermalmethod. The structures, morphologies and optical properties of core–shell CeO2nanospheres were analyzed by X-ray diffraction(XRD), TG, Fourier transform infrared spectroscopy, XRD, EDS, SAED, scanning electron microscopy and transmissionelectron microscopy, UV–Vis diffuse reflectance spectra, Raman analyses. The degradation efficiencies of core–shell CeO2nanospheres for methyl orange were as high as 93.49, 95.67 and 98.28% within 160 min, and the rates of photo degradationof methyl orange by core–shell CeO2nanospheres under UV-light were 0.01693, 0.01782 and 0.02375 min−1. Methyl orangewas degraded in photocatalytic oxidation processes, which mainly gave the credit to a large number of reactive species includingh+,surface superoxide species ·O2−, and ·OH radicals. The core–shell structure, small crystallite size and the conversionbetween Ce3+and Ce4+of CeO2nanospheres were of importance for its catalytic activity. These results demonstrated thepossibility of improving the efficient catalysts of the earth abundant CeO2catalysts.