Young-Hwan Chu

Synthesis of mesoporous silica fiber using spinning method

Abstract A very simple procedure for the synthesis of fibrous mesoporous silica using a spinning method was developed. It was based on the sol–gel process and solvent evaporation process using cetyltrimethylammonium chloride as a template. Fibrous mesoporous silica was drawn by using a viscous solution which consisted of a surfactant (cetylmethylammonium chloride) and hydrolyzed silica alkoxide (TMOS). Fibrous mesoporous materials have two distinct pores, 0.9 and 1.9 nm, with a specific surface area of about 580 m 2 /g in 1000 rpm of spinning speed. The intensity of the X-ray diffraction pattern of the mesoporous fibers was increased after both the fiber spinning and calcination process. Increasing the spinning speed from 500 to 2000 rpm in the spinning process increased the specific surface area of the mesoporous fibers from 547 to 605 m 2 /g, and simultaneously decreased the diameter of the fibers from 80 to 20 μm.

Effect of Pt Particle Size on the Durability of PEMFC

본 연구에서는 백금의 입자크기가 내구성과 활성에 미치는 영향을 고찰하였다. 상용 Pt/C의 열처리를 통해 백금 입자 크기를

Proton conducting silica mesoporous/heteropolyacid-PVA/SSA nano- composite membrane for polymer electrolyte membrane fuel cell

3.5{\sim}9\;nm

Evaluation of the Nafion effect on the activity of Pt–Ru electrocatalysts for the electro-oxidation of methanol

로 조절하였고, XRD와 TEM을 통해 이를 확인하였다. 촉매의 내구성 분석을 위해 가속 실험을 실시하였고, 촉매 활성 측정을 위해 산소환원반응 실험을 하였다. 백금의 입자크기를 증가시킬수록 내구성은 향상되었으나 촉매의 활성이 저하되었다. 즉 촉매의 내구성과 활성은 반비례관계가 성립된다는 것을 확인하였다. 그리고 저하된 촉매 활성과 내구성을 향상시키기 위해, 합금 촉매를 사용하였다.상용 Pt/C의 최대 전력 밀도는 약

Combinatorial investigation of Pt-Ru-M as anode electrocatalyst for direct methanol fuel cell

507.6\;mV/cm^2

A Simple CNT Supported Electrocatalysts Preparation Method by Electro-Reduction

이고, PtCo/C 합금촉매는

Sulfonated Poly(Ether Ether Ketone)-Based Composite Membrane for High Temperature Operation of PEMFC

585.8\;mV/cm^2

Stability and Activity of Pt-based Alloy Catalyst for PEMFC Cathode

이었다. 전기화학적 표면적은 상용 Pt/C는 약 60%정도 감소하였고, PtCo/C 합금촉매는 약 24%정도의 감소율을 나타냈다. 따라서 백금의 입자 크기 조절과 합금화를 통해 백금의 내구성과 활성을 동시에 높일 수 있었다. 【The influence of the particle size of platinum(Pt) on the stability and activity was studied. The particle size of platinum was controlled in the range of

Synthesis of Mesoporous Carbon with Graphite Pore Walls for Electrochemical Application

3.5{\sim}9\;nm

Carbon-Supported Electrocatalyst: Improvement of Thermal and Electrochemical Stability of PEMFC

by heat treatment of commercial Pt/C and confirmed by XRD and TEM. An accelerated degradation test was performed to evaluate the stability of platinum catalysts. Oxygen reduction reaction was monitored for the measurement of activity. As increasing the Pt particle size, the stability of Pt/C electrode was enhanced and the activity was reduced. It was confirmed that the stability of Pt/C electrode was in inverse proportion to the activity. PtCo/C alloy catalyst was used to improve the activity and stability of large-sized platinum particle. The maximum power density of commercial Pt/C was