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Zeda Meng,Wei Zhao,김석영 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.6
Reactive oxygen species (ROS) can be produced by the interactionsbetween sunlight and light-absorbing substances in aqueous environments,and these ROS are capable of destroying various organic pollutants inwastewater. In this study, the photocatalytic degradation of ammonia inpetrochemical wastewater was investigated by solar light photocatalysis. We used graphene oxide modified Ag2Se nanoparticles to enhance theactivity of photochemically generated oxygen (PGO) species. There wasa catastrophic decrease in the surface area and pore volume of theAg2Se-graphene oxide (Ag2Se-G) samples because of the deposition ofAg2Se. The generation of ROS was detected by the oxidation of 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). It wasrevealed that the photocurrent density and PGO effect increased with thegraphene oxide modified. The experimental results indicate that thisheterogeneous catalyst achieved a degradation of 88.43% under visiblelightirradiation. The NH3 degradation product was N2 and neither NO2−nor NO3− were detected.
Yang, Hexiang,Zhou, Mengkai,Meng, Zeda,Zhu, Lei,Chen, Zhigang,Oh, Won-Chun Materials Research Society of Korea 2015 한국재료학회지 Vol.25 No.3
Cubic mesocrystal $CeO_2$ was synthesized via a hydrothermal method with glutamic acid ($C_5H_9NO_4$) as a template. The XRD pattern of a calcined sample shows the face-centered cubic fluorite structure of ceria. Transmission electron microscopy (TEM) and the selected-area electron diffraction (SAED) pattern revealed that the submicron cubic mesocrystals were composed of many small crystals attached to each other with the same orientation. The UV-visible adsorption spectrum exhibited the red-shift phenomenon of mesocrystal $CeO_2$ compared to commercial $CeO_2$ particles; thus, the prepared materials show tremendous potential to degrade organic dyes under visible light illumination. With a concentration of a rhodamine B solution of 20 mg/L and a catalyst amount of 0.1 g/L, the reaction showed higher photocatalytic performance following irradiation with a xenon lamp (${\geq}380nm$). The decoloring rate can exceed 100% after 300 min.
Lei Zhu,조선복,Shu Ye,Kefayat Ullah,Zeda Meng,오원춘 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-
CoS2, CoS2–graphene and CoS2–graphene/TiO2 composite was synthesized by a facile sonochemical andhydrothermal method. X-ray diffraction, scanning electron microscopy with energy-dispersive X-rayanalysis, transmission electron microscopy, FT-IR, UV–vis and BET surface area was calculated bynitrogen adsorption were used. The FT-IR results illuminated that CoS2 and TiO2 band transfers electronsto graphene with functional groups attached. UV–vis patterns indicated that CoS2–graphene/TiO2 havegood photoinduction effects in visible light region. The photocatalytic activity of sample was evaluatedby measuring the degradation of organic pollutants such as methylene blue (MB), and industrial dyessuch as Texbrite BA-L (TBA) under visible light.
Wang, Chencheng,Jing, Lutian,Chen, Mengpin,Meng, Zeda,Chen, Zhigang,Chen, Feng,Oh, Won-Chun The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.1
A series of $CeO_2-TiO_2$ composite samples with different Ce/Ti molar ratios were prepared by the paper template. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm a face-centered cubic lattice of $CeO_2$ with Ce/Ti =8:2 or 9:1 and a two phase mixture of anatase titania and face-centered cubic ceria with Ce/Ti = 7 : 3. The field emission scanning electron microscopy (FESEM) results suggest that the products are micron braid structures consisting of fibers with diameters in a range of $1-6{\mu}m$ and lengths of several hundred micrometers. $N_2$ absorption-desorption testing shows that the composite at Ce/Ti molar fraction of 8 : 2 has the largest BET surface area (about $81m^2{\cdot}g^{-1}$). Compared to the pure $CeO_2$ sample, the composites show superior catalytic activity for $H_2$ reduction and CO oxidation. For the micron braid structure $CeO_2-TiO_2$ composite (Ce/Ti = 8 : 2), due to the high surface area and the solid solution with appropriate $Ti^{4+}$ incorporation, the CO conversion at about $280^{\circ}C$ was above 50% and at $400^{\circ}C$ was 100%.
Rich Se Nanoparticles Modified Mo-W18O49 as Enhanced Electrocatalyst for Hydrogen Evolution Reaction
Jun-hui Wang,Jia-Yao Tang,Jia-Yi Fan,Zeda Meng,Lei Zhu,오원춘 한국재료학회 2022 한국재료학회지 Vol.32 No.2
Herein a rich, Se-nanoparticle modified Mo-W18O49 nanocomposite as efficient hydrogen evolution reaction catalyst is reported via hydrothermal synthesized process. In this work, Na2SeSO3 solution and selenium powder are used as Se precursor material. The structure and composition of the nanocomposites are characterized by X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), EDX spectrum analysis and the corresponding element mapping. The improved electrochemical properties are studied by current density, and EIS analysis. The as-prepared Se modified Mo-W18O49 synthesized via Na2SeSO3 is investigated by FE-SEM analysis and found to exhibit spherical particles combined with nanosheets. This special morphology effectively improves the charge separation and transfer efficiency, resulting in enhanced photoelectric behavior compared with that of pure Mo-W18O49. The nanomaterial obtained via Na2SeSO3 solution demonstrates a high HER activity and low overpotential of -0.34 V, allowing it to deliver a current density of 10 mA cm2.
Xin Ni,Yuan Liang,Quanzi Pan,Hengjie Guo,Kai Chen,Bo Zhang,Shaocong Ni,Bin Sheng,Zeda Meng,Shouqing Liu,오원춘 한국재료학회 2023 한국재료학회지 Vol.33 No.11
Single-atom Pd clusters anchored on t-BaTiO3 material was synthesized using hydrothermal and ultrasonic methods for the effective piezoelectric catalytic degradation of pollutants using vibration energy. XRD patterns of BaTiO3 loaded with monoatomic Pd were obtained before and after calcining, and showed typical cubic-phase BTO. TEM and HAADF-STEM images indicated single-atom Pd clusters were successfully introduced into the BaTiO3. The piezoelectric current density of the prepared Pd-BaTiO3 binary composite was significantly higher than that of the pristine BaTiO3. Under mechanical vibration, the nanomaterial exhibited a tetracycline decomposition rate of ~95 % within 7 h, which is much higher than the degradation rate of 56.7 % observed with pure BaTiO3. Many of the piezo-induced electrons escaped to the Pd-doped BaTiO3 interface because of Pd’s excellent conductivity. Single-atom Pd clusters help promote the separation of the piezo-induced electrons, thereby achieving synergistic catalysis. This work demonstrates the feasibility of combining ultrasonic technology with the piezoelectric effect and provides a promising strategy for the development of ultrasonic and piezoelectric materials.