Flexible self-supported laser-induced graphene (LIG) electrode devices were facilely fabricated through laser ablation technique by employing commercial polyimide film as the precursor material. Compared with the widely used traditional glassy carbon electrodes, the resulted LIG electrodes displayed abundant porous structure and surface defects. Notably, the onestep yielded LIG electrode devices were endowed with large electrochemically active surface area and accelerated electron transfer ability. Benefiting from its superior electrochemical property, these unmodified LIG electrodes exhibited remarkable enhanced electrochemical oxidation reactivity toward the food additive molecule Allura Red. Based on the augmented oxidation signal of Allura Red molecules on the LIG electrodes, a novel electrochemical sensor with high sensitivity for the detection of Allura Red was successfully developed. The sensor demonstrated a linear detection range spanning from 5 nM to 1 μM and exhibited a detection limit as low as 2.5 nM. Besides, the sensitivity was calculated to be 240.62 μA μM−1 cm− 2. More importantly, the sensor manifested outstanding stability, reproducibility, and practicality, further emphasizing its potential for real-world application.

Oxygen-rich porous carbon is of great interest for energy storage applications due to its improved local electronic structures compared with unmodified porous carbon. However, a tunable method for the preparation of oxygen-rich porous carbon with a special microstructure is still worth developing. Herein, a novel modification of porous carbon with different microstructures is facilely prepared via low-temperature solvothermal and KOH activation methods that employ the coal tar and eight substances, such as cellulose as carbon source and modifier, respectively. By testing the yield, surface group structure, lattice structures, morphology, thermal weight loss, and specific capacitance of carbonaceous mesophase, cellulose–hydrochloric acid is identified as the additive for the preparation of oxygen-rich coal tar-based porous carbon. The obtained porous carbon displays a specific surface area of up to 859.49 m2 g− 1 and an average pore diameter of 2.39 nm. More importantly, the material delivers a high capacity of 275.95 F g− 1 at 0.3 A g− 1 and maintains a high capacitance of 220 F g− 1 even at 10 A g− 1. When in a neutral electrolyte, it can still retain a reversible capacity of 236.72 F g− 1 at 0.3 A g− 1 and 136.79 F g− 1 at 10 A g− 1. This work may provide insight into the design of carbon anode materials with high specific capacity.

Aurantii Fructus Immature (AFI) and Aurantii Fructus (AF) are two important traditional Chinese herbs. As the harvesting time varies, the medicinal value of the plants is not uniform. Consequently, it has been difficult to quickly recognize them within the realm of traditional Chinese medicine. Separation and detection technologies are employed in combination to create fingerprints for identification. We proposed the utilization of graphene-assisted electrochemical fingerprint technology to acquire fingerprints of two varieties of medicinal materials. Simultaneously, we also obtained their fingerprints through HPLC. Two fingerprint recognition technologies were compared for their effectiveness. The findings demonstrate that the signals obtained through electrochemical fingerprinting have a higher recognition rate.

Double-layer capacitors (DLCs) are developed with high surface electrodes to achieve a high capacitance value. In the present work, the initial bulk concentration of 1 mol/m3 and 3 mol /m3 are selected to show the consequential effects on the performance of a double-layer capacitor. A 1D model of COMSOL Multiphysics has been developed to analyze the electric field and potential in cell voltage, the electric displacement field and polarization induced by the field, and energy density in a double-layer structure. The electrostatics and the electric circuit modes in COMSOL are used to simulate the electrochemical processes in the double-layer structure. The analytical analysis of a double-layer capacitor with different initial bulk concentrations is investigated by using Poisson-Nernst-Plank equations. From the simulation results, the differential capacitance changes as a function of compact layer thickness and initial bulk concentration. The energy density varies with the differential capacitance and voltage window. The values of energy density are dominated by the interaction of ions in the solution and electrode surface.

Ni-rich계 양극 소재는 낮은 가격과 높은 용량으로 인해 고용량 달성을 위한 상용화 소재로 주목받고 있지만, 이 소재의 경 우 전기화학적 불안정성으로 인한 한계를 가진다. 그래서 다양한 표면 코팅 방법을 통해 성능향상을 이루고 있지만, 성능향상이 소 재와 코팅 방법때문인지 또는 코팅 범위가 넓어진 것 때문인지는 모호하게 남아 있다. 본 연구에서는 전이금속으로 양극 활물질을 코팅할 때 전구체 코팅 범위에 따른 리튬이온배터리 전기화학 성능평가를 분석하였다. 상업용 LiNi0.8Co0.1Mn0.1O2 양극 소재 표면을 에탄올 용액에 용해된 리튬-코발트와 리튬-주석 아세테이트 전구체를 코팅하였고, 교반속도를 다르게 하여 (200 rpm 및 600 rpm) 전구체 코팅 범위를 다르게 하였다. 리튬-코발트 아세테이트 전구체의 경우 교반속도가 증가할수록 코팅 범위가 증가하였지만, 리튬 -주석 아세테이트 전구체의 경우 교반속도가 증가할수록 코팅 범위가 감소하였다. 하지만 원소의 종류에 관계없이 코팅 범위가 넓 은 경우에 상대적으로 우수한 전기화학적 성능을 나타내었다. 코팅된 양극 활물질의 물리적 특성은 SEM 및 XRD를 이용하여 분석하 였으며, 전기화학적 성능은 초기 충·방전 용량, 사이클 안정성 및 율속특성 테스트를 통해 조사하였다.

본 연구는 절탄기 튜브의 저온부식 손상을 방지하기 위해 Inconel 625 용사재료를 활용하여 아크 열용사 코팅기술 적용 후 실링 처리를 실시하였다. 용사코팅(TSC) 층의 내식성 분석을 위해 0.5 wt% 황산 수용액에서 다양한 전기화학적 실험을 진행하였다. 양극분극 실험 후에는 주사전자현미경과 EDS 성분분석을 통해 부식 손상 정도를 파악하였다. 자연전위 계측 시 TSC+실링처리(TSC+Sealing)의 안정적인 전위 형성을 통해 실링처리 효과를 확인하였다. 양극분극 실험 결과 TSC와 TSC+Sealing에서 부동태 영역이 확인되었으며, 부식 손상 역시 관찰되지 않아 내식성이 개선되었다. 더불어 타펠분석에 의해 산출된 부식전위와 부식전류밀도 분석 결과 TSC+Sealing의 내식성이 가장 우수하게 나타났다.

본 연구는 기계화학적 활성화 된 스카치테이프가 금속 이온 수용액에서 유발하는 자발적 금속 나노입자 필름 형성의 구동력과 그 크기를 전기화학적 방법으로 분석했다. 은 필름이 형성된 테이프를 질산에 녹이고, 완충용액과 섞어 전기화학 측정용 샘플을 준비했다. 양극 벗김 전압전류법의 피크 신호를 통해, 은 입자의 자발적 환원에 소모된 전하량을 측정했다. 이를 검정 곡선에 대입하여, 환원된 은의 양을 구했다. 그 결과 은의 양이 선행 연구 대비 106배 많은 점, 수용액에서 전하를 가진 이온들의 짧은 수명을 참고하여, 자발적 반응의 구동력을 라디칼로 결론 냈다.

본 연구에서는 “이온젤” 이라고 불리는 고분자 기반의 PVA(polyvinyl alcohol) 기반의 고체 전 해질에 이온성 액체 BMIMBF4 (1-buthyl-3-methylimidazolium tetrafluoroborate)를 첨가하여 제조한 전 고체 전해질과 활성탄소와 금속유기골격체 복합재료 기반의 전극 재료를 이용하여 슈퍼커패시터를 제작 하였으며, 유기골격체의 유 무에 따른 전기화학적 특성을 분석하여 보았다. 슈퍼커패시터의 전기화학적 특 성은 순환전압전류법(CV), 전기화학적 임피던스 분광법(EIS) 및 전정류 충·방전법(GCD)을 통하여 비교 및 분석하여 보았다. 그 결과로, 금속유기골격체가 함유되지 않은 슈퍼커패시터의 전기용량값은 380 F/g 으로 확인 할 수 있었고, 이 값은 금속유기골격체를 첨가하였을 때 340 F/g로 감소하는 현상을 확인할 수 있었 다. 이러한 결과로 1 wt%의 금속유기골격체의 함유량은 전기화학적 특성 감소에 영향을 주는 것으로 사료 되며 이러한 결과를 바탕으로 금속유기골격체의 첨가량을 최적화 할 필요가 있다고 판단된다

Transition metal oxide is widely used as a water electrolysis catalyst to substitute for a noble metal catalyst such as IrO2 and RuO2. In this study, the sol-gel method is used to synthesize the CuxCo3-xO4 catalyst for the oxygen evolution reaction (OER),. The CuxCo3-xO4 is synthesized at various calcination temperatures from 250 ℃ to 400 ℃ for 4 h. The CuxCo3- xO4 synthesized at 300 ℃ has a perfect spinel structure without residues of the precursor and secondary phases, such as CuO. The particle size of CuxCo3-xO4 increases with an increase in calcination temperature. Amongst all the samples studied, CuxCo3- xO4, which is synthesized at 300?, has the highest activity for the OER. Its onset potential for the OER is 370 mV and the overpotential at 10 mA/cm2 is 438 mV. The tafel slope of CuxCo3-xO4 synthesized at 300 ℃ has a low value of 58 mV/dec. These results are mainly explained by the increase in the available active surface area of the CuxCo3-xO4 catalyst.

An enantioselective recognition of D- and L-tryptophan (Trp)-b-cyclodextrin (CD) inclusion complex was performed using electrochemical and FT-Raman spectroscopic analysis. From the electrochemical analysis, the selectivity coefficient (KDL) of b-CD inclusion complexes was found higher than that of the D- and L-Trp in phosphate buffered saline (PBS, pH=7.0) solution. The percentage of enantioselectivity (I%ee) for peak current of D-Trp-b-CD inclusion complexes was observed higher than that of L-Trp-b-CD inclusion complexes in PBS solution. From Raman spectroscopy, chemical shift difference (D, cm-1) for the C=C stretch, ring vibration, and ring breathing of D-Try-b-CD inclusion complex were observed higher than that of L-Trp-b-CD inclusion complex. The electrochemical and Raman spectroscopic analyses were found very useful for chiral detection of racemic amino acid in the presence of b-CD.

In this study, an electro-catalyst of Pt nanoparticles supported by polypyrrole-functionalized graphene (Pt/PPy-reduced graphene oxide [RGO]) is reported. The Pt nanoparticles are deposited on the PPy-RGO composite by chemical reduction of H2PtCl6 using NaBH4. The presence of graphene (RGO) caused higher activity. This might have been due to increased electro-chemically accessible surface areas, increased electronic conductivity, and easier charge-transfer at polymer-electrolyte interfaces, allowing higher dispersion and utilization of the deposited Pt nano-particles. Microstructure, morphology and crystallinity of the synthesized materials were investigated using X-ray diffraction and transmission electron microscopy. The results showed successful deposition of Pt nano-particles, with crystallite size of about 2.7 nm, on the PPy-RGO support film. Catalytic activity for methanol electro-oxidation in fuel cells was investigated using cyclic voltammetry. The fundamental electrochemical test results indicated that the electro-catalytic activity, for methanol oxidation, of the Pt/PPy-RGO combination was much better than for commercial catalyst.