활성탄소섬유의 비표면적에 따른 유해가스 흡착 및 전기화학적 감응 특성

강진균,정용식,배병철,류지현 한국접착및계면학회 2020 접착 및 계면 Vol.21 No.2

Recently, there has been growing interest in the study of removal of harmful and hazardous pollutants emitted by industrial activities. In this study, we have developed porous activated carbon fibers prepared by a water vapor activation method and analyzed the adsorptions of the harmful gases with electrochemical responses of activated carbon fibers. To control the uniformity of pore structures, active reaction areas, and active sites, the reaction conditions of activation temperatures were varied from 750 to 850 oC with the predetermined reaction time intervals (30 to 240 min). The SO2 and NO gas adsorptions of activated carbon fibers prepared by various reaction conditions were analyzed and monitored by electrochemical sensor responses. In particular, the activated carbon fibers prepared at the reaction temperature of 850 °C and time of 45 min showed the highest specific surface area (1,041.9 m2/g) and pore characteristics (0.42 cm3/g), and excellent adsorption capabilities of SO2 (1.061 mg/g) and NO (1.210 mg/g) gases, respectively.

Ultrathin Ni-Mo oxide nanoflakes for high-performance supercapacitor electrodes

Chavan, Harish S.,Hou, Bo,Ahmed, Abu Talha Aqueel,Kim, Jongmin,Jo, Yongcheol,Cho, Sangeun,Park, Youngsin,Pawar, Sambhaji M.,Inamdar, Akbar I.,Cha, Seung Nam,Kim, Hyungsang,Im, Hyunsik Elsevier 2018 Journal of Alloys and Compounds Vol.767 No.-

<P><B>Abstract</B></P> <P>Supercapacitors based on nanomaterial electrodes exhibit great potential as power sources for advanced electronic devices. From a practical viewpoint, it is desirable to fabricate highly active and sustainable nanomaterial electrodes consisting of non-precious elements using a simple technique in a controllable way. In this work, we report the synthesis of a self-assembled ultra-thin porous nanoflake Ni-Mo oxide (NMO) film using the successive ionic layer adsorption and reaction (SILAR) technique. The nanoflake NMO thin film electrode with a large electrochemically active surface area of ∼108 cm<SUP>−2</SUP> exhibits a high specific capacitance of 1180 Fg<SUP>−1</SUP> at a current density of 1 Ag<SUP>−1</SUP> and excellent rate capability, with a negligible capacity loss of 0.075% per cycle. Even at a high current rate of 10 A g<SUP>−1</SUP> it retains a capacity of 600 Fg<SUP>−1</SUP>. The highest energy and power densities obtained are 119 Whkg<SUP>−1</SUP> and 15.7 kWkg<SUP>−1</SUP>, respectively. Electrochemical impedance spectroscopy analyses reveal that the electrode has considerably low charge transfer resistance. The observed excellent electrochemical energy storage performance of the nanoflake NMO electrode with a nanoporous surface is due to the synergetic effects of the large electrochemically active surface area, enhanced ion diffusion, and improved electrical conductivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ultra-thin porous Ni-Mo oxide nanoflakes self-assemble on stainless steel via a SILAR method. </LI> <LI> Large electrochemically-active surface area, enhanced ion diffusion and robust adhesion result in superior performance. </LI> <LI> High specific capacitance of 1180 F/g and energy density of 119 Wh/kg at 1 A/g are achieved. </LI> </UL> </P>

Comparison of Catalytic Activity for Methanol Electrooxidation Between Pt/PPy/CNT and Pt/C

Lee, C.G.,Baek, J.S.,Seo, D.J.,Park, J.H.,Chun, K.Y. The Korean Electrochemical Society 2010 한국전기화학회지 Vol.13 No.4

This work explored the catalytic effect of Pt in multi-wall carbon nanotube and poly-pyrrole conductive polymer electrocatalysts (Pt/PPy/MWCNT). A home-made Pt/PPy/MWCNT catalyst was first evaluated by comparing its electrochemical active surface area (ESA) with E-Tek commercial catalysts by cyclic voltammetry in $H_2SO_4$ solution. Then, the methanol oxidation currents of Pt/PPy/MWCNT and the hydrogen peaks in $H_2SO_4$ solution were serially measured with microporous electrode. This provided the current density of methanol oxidation based on the ESA, allowing a quantitative comparison of catalytic activity. The current densities were also measured for Pt/C catalysts of E-Tek and Tanaka Precious Metal Co. The current densities for the different catalysts were similar, implying that catalytic activity depended directly on the ESA rather than charge transfer or electronic conductivity.

Comparison of Catalytic Activity for Methanol Electrooxidation Between Pt/PPy/CNT and Pt/C

이충곤,J.-S. Baek,D.-J. Seo,J.-H. Park,전경용 한국전기화학회 2010 한국전기화학회지 Vol.13 No.4

This work explored the catalytic effect of Pt in multi-wall carbon nanotube and poly-pyrrole conductive polymer electrocatalysts (Pt/PPy/MWCNT). A home-made Pt/PPy/MWCNT catalyst was first evaluated by comparing its electrochemical active surface area (ESA) with E-Tek commercial catalysts by cyclic voltammetry in H2SO4 solution. Then, the methanol oxidation currents of Pt/PPy/MWCNT and the hydrogen peaks in H2SO4 solution were serially measured with microporous electrode. This provided the current density of methanol oxidation based on the ESA, allowing a quantitative comparison of catalytic activity. The current densities were also measured for Pt/C catalysts of E-Tek and Tanaka Precious Metal Co. The current densities for the different catalysts were similar, implying that catalytic activity depended directly on the ESA rather than charge transfer or electronic conductivity.

Improvement in Catalytic Activity of Ag Catalyst via Simple Mixing with Carbon

Choun, Myounghoon,Baek, Ji Yun,Eom, Taehyoung Korea Electric Power Corporation 2019 KEPCO Journal on electric power and energy Vol.5 No.4

In this study we investigate catalytic activity and selectivity of mixture of Ag and ketjenblack according to their ratios by product analysis and electrochemical experiments, such as cyclic voltammetry, linear sweep voltammetry and chronoamperometry. We reveal that catalytic activity toward CO2 reduction to CO is improved by simple mixing Ag nanoparticle and ketjenblack because addition of ketjenblack suppresses aggregation of Ag nanoparticles and brings increase in electrochemical active surface area. However, excess amount of ketjenblack rather inhibit the CO2 reduction to CO. These observations provide clues to develop highly active Ag catalyst or electrode toward electrochemical reduction of CO2.

Highly bioactive and low cytotoxic Si-based NiOOH nanoflowers targeted against various bacteria, including MRSA, and their potential antibacterial mechanism

권기학,박종덕,이선화,한인,유종성,이도남 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

With the emergence of new drug-resistant microorganisms, the development of effective antimicrobialagents is urgently required. Core-shell-structured nanomaterials have received considerable attention asantibacterial agents. We prepared a bioactive core-shell-structured silicon-based NiOOH nanoflower(Si@NiOOH) targeted against various bacteria using a modified chemical bath deposition method. Further, we investigated its potential antibacterial mechanism by evaluating electrochemical propertiesin a redox reaction with ascorbic acid, measuring metal ion release, and analyzing the surface area. Thebactericidal rate of Si@NiOOH at 200 mg/mL towards Pseudomonas aeruginosa, Klebsiella pneumoniae, andmethicillin-resistant Staphylococcus aureus was as high as 99.9%. Si@NiOOH maintained its originalmorphology after killing the bacteria and exhibited negligible cytotoxicity towards mouse embryonicfibroblasts. The excellent antibacterial activities of Si@NiOOH are possibly derived from its high surfacearea, providing a wide active site attached to the cell wall, and the high oxidative potency of the Ni(III)cations existing on its surface. The high antibacterial activity and low cytotoxicity of the nanoflower makeit a promising tool for promoting wound healing and for use with medical devices and implants.

Surface modifi cation and electrochemical performance of KMnO 4 -ultra-surface area activated carbon (USAC) composites as cathode material

Zambaga Otgonbayar,Kamrun Nahar Fatema,Md Nazmodduha Rafat,Jihyeon Ryu,양선혜,Ick-Jun Kim,Won Chun Oh 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.5

The goal of this study was to analyse the impact of a combination of a sub-active material (KMnO 4 ) with surface modifi cation to the activated carbon surface for enhanced cathode performance. Activated carbon with ultra-specifi c surface area (USAC, TCK-PBM, 2560.4 m 2 /g) was used for the preparation of our composite with potassium permanganate (KMnO 4 ). The physical characteristics of this As-treated USAC sample were analysed through XRD, SEM and EDX analysis. The XRD analysis was used to examine structural properties; surface analysis undertaken by SEM; EDX analysis was used to measure the metal content of the sample as well as the content after treatment with KMnO 4 . It was shown USAC treated with KMnO 4 had more than a 10.5 μg acidic group by the Boehm titration method. The electrochemical properties of KMnO 4 -USAC were investigated for varying electrolyte concentration (0.1, 0.5, 1.2 and 6 M) at ambient temperature (25 °C) and the electrode showed great electrochemical performance after ten cycles.

Electrochemical properties of hybrid typed electrocatalyst using Pt/carbon molecular sieve synthesized by zeolite template and Pt carbon black

Yang, H.N.,Park, S.H.,Lee, D.C.,Yi, S.C.,Kim, W.J. Elsevier 2013 Microporous and mesoporous materials Vol.172 No.-

Hybrid-typed Pt electrocatalyst using Pt-carbon molecular sieve (Pt-CMS) synthesized by zeolite template method and commercial Pt-carbon black (Pt-CB) is prepared with different ratios of Pt-CB to Pt-CMS. Their physical and electrochemical properties are characterized using X-ray diffraction (XRD), transmission electron micrograph (TEM) and Brunauer-Emmet-Teller method (BET). Pt nanoparticles of 2-4nm are synthesized and successfully dispersed onto CMS by polyol method and comparable with that of commercial Pt-CB. Cyclic voltammetric analysis is conducted to estimate electrochemical active surface area (ECSA). The cell test is conducted for the various membrane electrolyte assemblies (MEAs) fabricated with different catalysts such as Pt-CB, Pt-CMS, various hybrid-typed Pt-CBx/Pt-CMS100-x named as Pt-CBx/CMS100-x. The cell performance is fairly consistent with ECSA and the MEA fabricated with equal mass fraction of Pt-CB and Pt-CMS (Pt-CB50/CMS50) shows the best cell performance, indicating a significant dependence on pore structure of carbon support.

Advanced calculation methodology for an active surface area of composite electrodes for reliable electrochemical models

이효빈,정승원,송지훈,박주남,이용민 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.-

Co‑doped amorphous MoSx for efficient hydrogen evolution reaction in acid condition

Lang Gan,Jincheng Liu,Yanjie Ren,Zhongyi Xiong,Kang Chen 한국탄소학회 2023 Carbon Letters Vol.33 No.5

Amorphous molybdenum sulfide ( MoSx) has been regarded as a promising hydrogen evolution reaction (HER) catalyst due to its mild preparation conditions and low-cost precursor materials. In this work, we report a simple strategy combining the growth of amorphous MoSx on the surface of metal organic frameworks (ZIF-67) and annealing treatment to prepare Co-doped MoSx nanopolyhedrons (denoted as CoMoSx NPs). The CoMoSx NPs exhibit excellent HER activity in acid condition with an overpotential of 188 mV at a current density of 10 mA cm? 2 (η10), and a relatively stable overpotential after 2000 cyclic voltammetry (CV) cycles testing. The excellent HER performance of the CoMoSx NPs can be attributed to the doping of Co element adjust the electronic structure and increase the conductivity of catalyst, and the nanopolyhedrons structure which can expose more active sites for HER electrocatalytic. This study offers a low-cost and simple strategy to prepare high-activity HER catalyst, which holds great promises in developing advanced electrocatalysts for energy storage.