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( Guo Wenwu ),안상현 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
The development of an efficient water electrolyser for sustainable hydrogen production still remains limited by the insufficient performance of the electrode.Herein, we report cost-effective fabrication of Cu-Co-P catalysts on a carbon paper substrate (Cu-Co-P/CP) via simple electrodeposition at room temperature and under ambient pressure. which is directly usable for an anion exchange membrane water electrolyser (AEMWE). The as-obtained Cu-Co-P/CP electrode was fully characterized and the structure, surface morphology and composition of deposits were studied to understand their effect on the catalytic activity for HER. Moreover, the electrochemical test indicated that the incorporation of Cu content into the Co-P structure results in enhancement ofcatalytic activity for hydrogen evolution in an alkaline electrolyte. An AEMWE single cell was constructed by employing the Cu-Co-P/CP cathode coupled with a commercial IrO<sub>2</sub>/CP anode, which exhibited acceptable cell performance.
Stacked graphene-MoS<sub>2</sub> photocatalyst for hydrogen evolution reaction
( Guo Wenwu ),김수영 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
The graphene and MoS<sub>2</sub> synthesized by chemical vapor deposition have been wildly studied and applied in many fields. Many researched about graphene- or MoS<sub>2</sub>-based catalyst for hydrogen evolution reaction(HER) have been reported. In order to modify the electronic structure of graphene, doping method has been wildly investigated. It is reported that the graphene can be n-doped by stacking on MoS<sub>2</sub> because there is a work function difference between two materials. In this work, a graphene-MoS<sub>2</sub> photocatalyst was made by stacking graphene on MoS<sub>2</sub> and loaded on the p-Si electrode for water splitting to produce hydrogen. The performance of the stacked photocatalyst was checked by HER measurement and the respective quality of the graphene and MoS<sub>2</sub> will be discussed.
An ultra-low loading iridium on porous gold support for proton exchange membrane water electrolyzer
김현기,김준형,( Guo Wenwu ),한경호,홍석진,안상현 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
With interest in global warming, hydrogen produced by water electrolysis is a promising candidate for alternative for fossil fuel. For proton exchange membrane water electrolyzer (PEMWE), Ir-based oxide used as an anode which showed high performance for oxygen evolution reaction (OER). However, its high price and scarcity prevent from commercialization. In this study, low loading Ir-based catalyst on Au were fabricated by self-terminated electrodeposition and subsequent oxidation process. By normalizing the geometric OER activity by electrochemical surface area, intrinsic OER activities were obtained. Through controlling the number of Ir deposition and oxidation process, the Ir valency and electronic structure were modified. Conclusively, it was confirmed that the intrinsic OER activity was strongly affected by electronic structure for Ir-Au interface. Then, fabricated electrode was employed for an anode of PEMWE single-cell and showed remarkable mass activity.
Electrodeposited rhenium–cobalt alloy with high activity for acidic hydrogen evolution reaction
김현기,김준형,한경호,Wenwu Guo,홍석진,박주혜,안상현 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.95 No.-
The development of high-performance electrodes for hydrogen evolution reaction (HER) is essential forcommercialization of water electrolyzers. Among the promising candidate for HER catalyst, Re and itsoxide display an optimal hydrogen binding energy to that of Pt. Nevertheless, only a few studies havereported the acidic HER catalysts with the high overpotentials (>100 mV at –10 mA cm–2). Furthermore,Re transition metal alloy for the acidic HER catalyst have rarely been reported. Herein, we report a CoRealloy catalyst for the acidic HER, which was fabricated by electrodeposition on carbon paper (CP) bycontrolling the electrodeposition. The optimized CoRe/CP electrode exhibited a higher HER activity thanthose of the other Re-based catalysts with an overpotential of 45.1 mV at10 mA cm–2. The activationenergy for the HER of CoRe/CP, which was calculated from the Arrhenius plot, demonstrated a lower valueof 8.99 kJ mol–1 K–1.
연규림,김준형,김현기,Wenwu Guo,한경호,홍석진,안상현 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.8
The development of high-performance and low-cost electrodes is essential for hydrogen production using a proton exchange membrane water electrolyzer (PEMWE). Herein, we report an electrochemical method for the fabrication of a Ni-P based cathode for a PEMWE single cell. A porous copper foam (CF) is fabricated on carbon paper (CP) by two-step electrodeposition to obtain a large number of active sites for Ni-P formation. The high conductivity of the Cu metallic support is expected to reduce the charge transfer resistance. After the Ni-P electrodeposition on CF, an anodic leaching process is conducted for the selective dissolution of the excess Ni metal formed during the electrodeposition, thus enabling the modification of the electronic structure of the catalyst. The electrode optimized in halfcell tests is used as the cathode for a PEMWE single cell. The PEMWE cells exhibit a current density of 0.67 A/cm2 at 2.0 Vcell which is higher than or comparable to the performance previously reported in the literature.
Repair Decision Based on Sensitivity Analysis for Aero-Engine Assembly
Yanhui Sun,Junkang Guo,Jun Hong,Guanghui Liu,Wenwu Wu,Cong Yue 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.3
Strict requirements for concentricity of the multistage high pressure rotor of an aero-engine are employed to guarantee performances such as vibration. Tedious and time-wasting trial assembly by adjusting the installation angles of stages is needed to meet the requirements due to the lack of effective analysis methods. Furthermore, there is no quick way to find out where the problem is and how to repair the parts when the installation-angle-adjusting method fails. This article focuses on a solution to optimize the installation angle of each stage and to make repair decisions in the assembly process. The run-out data are processed by least square method to get the spatial positions and attitudes of flanges and a deviation propagation analysis model is built by virtue of homogeneous coordinate transformation theory to predict the accumulative errors of each stage. The eccentricities of stages are evaluated with reference to the common axis and the installation angles of stages are optimized by minimizing the sum of eccentricities. Sensitivities of eccentricity, eccentric angle and parallelism of each stage are analyzed and repair decisions for parts are made to meet more strict requirements. An example of a three-stage subassembly is presented to demonstrate the solution.
Tungsten Trioxide Doped with CdSe Quantum Dots for Smart Windows
Hasani, Amirhossein,Le, Quyet Van,Tekalgne, Mahider,Guo, Wenwu,Hong, Sung Hyun,Choi, Kyoung Soon,Lee, Tae Hyung,Jang, Ho Won,Kim, Soo Young American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.50
<P>Nanocrystal quantum dots (QDs) provide tunable optoelectronic properties on the basis of their dimension. CdSe QDs, which are size-dependent colloidal nanocrystals, are used for efficient electrochromic devices owing to their unique properties in modulating quantum confinement, resulting in enhanced electron insertion during the electrochromic process. Incorporating a well-known metal oxide electrochromic material such as WO<SUB>3</SUB> into CdSe QDs enhances the redox process. Herein, we propose a facile method for producing and optimizing CdSe QDs doped in WO<SUB>3</SUB>. The fabrication of the electrochromic film involves a solution and annealing process. Moreover, the effect of the QD size to optimize the electrochromic layer is studied. As a result, the coloration efficiency of WO<SUB>3</SUB> and optimized CdSe QD-WO<SUB>3</SUB> are obtained as 68.6 and 112.3 cm<SUP>2</SUP>/C, respectively. Thus, size-tunable nanocrystal QDs combined with a metal oxide yield high-performance electrochromic devices and are promising candidates for producing smart windows.</P> [FIG OMISSION]</BR>