Graphene Quantum Dots (GQDs), zero-dimensional nanoparticles which are derived from carbon-based sources owned the new pavement for the energy storage applications. With the varying synthesis routes, the in-built properties of GQDs are enhanced in different categories like quantum efficiency, nominal size range, and irradiation wavelength which could be applied for the several of energy and optoelectronics applications. GQDs are especially applicable in the specific energy storage devices such as super capacitors, solar cells, and lithium-ion batteries which were demonstrated in this work. This paper critically reviews about the synthesis techniques used for the GQDs involving energy storage applications with increased capacitance, energy conversion, retention capability, and stability.

Zinc selenide (ZnSe) nanoparticles were synthesized in aqueous solution using glutathione (GSH) as a ligand. The influence of the ligand content, reaction temperature, and hydroxyl ion concentration (pH) on the fabrication of the ZnSe particles was investigated. The optical properties of the synthesized ZnSe particles were characterized using various analytical techniques. The nanoparticles absorbed UV-vis light in the range of 350-400 nm, which is shorter than the absorption wavelength of bulk ZnSe particles (460 nm). The lowest ligand concentration for achieving good light absorption and emission properties was 0.6 mmol. The reaction temperature had an impact on the emission properties; photoluminescence spectroscopic analysis showed that the photo-discharge characteristics were greatly enhanced at high temperatures. These discharge characteristics were also affected by the hydroxyl ion concentration in solution; at pH 13, sound emission characteristics were observed, even at a low temperature of 25oC. The manufactured nanoparticles showed excellent light absorption and emission properties, suggesting the possibility of fabricating ZnSe QDs in aqueous solutions at low temperatures.

Zinc-ion Batteris (ZIBs) are recently being considered as energy storage devices due to their high specific capacity and high safety, and the abundance of zinc sources. Especially, ZIBs can overcome the drawbacks of conventional lithium ion batteris (LIBs), such as cost and safety issues. However, in spite of their advantages, the cathode materials under development are required to improve performance of ZIBs, because the capacity and cycling stability of ZIBs are mainly influenced by the cathode materials. To design optimized cathode materials for high performance ZIBs, a novel manganese oxide (MnO2) coated graphite sheet is suggested herein with improved zinc-ion diffusion capability thanks to the uniformly decorated MnO2 on the graphite sheet surface. Especially, to optimize MnO2 on the graphite sheet surface, amounts of percursors are regulated. The optimized MnO2 coated graphite sheet shows a superior zinc-ion diffusion ability and good electrochemical performance, including high specific capacity of 330.8 mAh g−1 at current density of 0.1 A g−1, high-rate performance with 109.4 mAh g−1 at a current density of 2.0 A g−1, and remarkable cycling stability (82.2 % after 200 cycles at a current density of 1.0 A g−1). The excellent electrochemical performance is due to the uniformly decorated MnO2 on the graphite sheet surface, which leads to excellent zinc-ion diffusion ability. Thus, our study can provide a promising strategy for high performance next-generation ZIBs in the near future.

Necessity of novel energy storage devices extensively increased due to consumption of high power in various devices. To address the issues, in this report, we are addressing with a composite Iron Sulfide/reduced Graphene Oxide ( Fe3S4/rGO) synthesized using the standard solvothermal method. X-ray diffraction and Field Emission Scanning Electron Microscope analysis results confirmed that Face-Centered cubic crystal structure of Fe3S4 and rGO’s surface is decorated with a mean diameter of < 50 nm Fe3S4 respectively. Transmission Electron Microscopy images show further evidence that dispersed Fe3S4 on the rGO surface. Fe3S4/ rGO exhibits specific capacitance of 560 F/g than its individual counterparts ( Fe3S4 = 200 F/g and rGO = 145 F/g) at 1 A/g of current density and maximum cyclic stability of 91% capacitance retention after 2000 cycles that may be the influence of synergy between the composite materials.

Continuous synthesis of high-crystalline carbon nanotubes (CNTs) is achieved by reconfiguring the injection part in the reactor that is used in the floating catalyst chemical vapor deposition (FC-CVD) process. The degree of gas mixing is divided into three cases by adjusting the configuration of the injection part: Case 1: most-delayed gas mixing (reference experiment), Case 2: earlier gas mixing than Case 1, Case 3: earliest gas mixing. The optimal synthesis condition is obtained using design of experiment (DOE) in the design of Case 1, and then is applied to the other cases to compare the synthesis results. In all cases, the experiments are performed by varying the timing of gas mixing while keeping the synthesis conditions constant. Production rate (Case 1: 0.63 mg/min, Case 2: 0.68 mg/min, Case 3: 1.29 mg/min) and carbon content (Case 1: 39.6 wt%, Case 2: 57.1 wt%, Case 3: 71.6 wt%) increase as the gas-mixing level increases. The amount of by-products decreases stepwise as the gas-mixing level increases. The IG/ID ratio increases by a factor of 7 from 10.3 (Case 1) to 71.7 (Case 3) as the gas-mixing level increases; a high ratio indicates high-crystalline CNTs. The radial breathing mode (RBM) peak of Raman spectrograph is the narrowest and sharpest in Case 3; this result suggests that the diameter of the synthesized CNTs is the most uniform in Case 3. This study demonstrates the importance of configuration of the injection part of the reactor for CNT synthesis using FC-CVD.

A facile microwave assisted solvothermal process is designed for fabricating SnS nanoparticles decorated on graphene nanosheet, which used as visible light driven photocatalyst. Some typical characterization techniques such as XRD, FT-IR, SEM with EDX analysis, and TEM and BET analysis are used to analyse the physical characteristics of as-prepared samples. Spherical SnS nanoparticles are uniformly dispersed on the surface of graphene nanosheet due to ammonia, which can prevent the aggregation of graphene oxide. Meanwhile, microwave radiation provides fast energy that promotes the formation of spherical SnS nanoparticles within a short time. The visible light photocatalytic activity of as-prepared SnS-GR nanocomposites is analysed through photodegradation efficiency of methylene blue with high concentration. According to the higher photocatalytic property, the as-prepared SnS-GR nanocomposites can be expected to be an efficient visible light driven photocatalyst. After five cycles for decolorization, the rate decreases from 87 % to 78 % (about 9 %). It is obvious that the photocatalytic activity of SnS-GR nanocomposite has good repeatability.

본 연구에서는 두 종류의 도너-억셉터 (D-A) 타입 고분자들을 Stille coupling 반응을 통하여 중합한 뒤, 이들 을 고분자 기반 유기 태양전지의 광활성 층으로 적용하였다. Benzodithiophene 전자 주게와 pyrazinoquinoxaline 전 자 받게를 활용하여 고분자들을 합성하였고, 전자 주게와 전자 받게가 직접 연결된 고분자를 PB-TMPQ 그리고 둘 사 이에 티오펜 π-bridge가 도입된 고분자를 PB-TTMPQ라 각각 명명하였다. 기본적인 화학 구조의 검증과 더불어, 고분 자들의 광학적 및 전기화학적 특성에 대한 분석 또한 실시하였다. 최종적으로 inverted-type 구조의 소자를 이용하여 고분자들의 광전지 특성들을 분석하였으며, PB-TMPQ와 PB-TTMPQ의 전력변환 효율은 각각 1.01%로 0.83%로 관측 되었다. 따라서, π-bridge의 도입이 pyrazinoquinoxaline 기반 고분자의 광전지 특성을 큰 영향을 미친다는 것이 확인 되었으며, 이러한 결과는 향후 pyrazinoquinoxaline 기반 고분자의 구조-물성 간 상관관계 연구에 활용될 수 있을 것 이다.

In this work, Ag3PO4/In2S3 nanocomposites with low loading of In2S3 (5-15 wt %) are fabricated by two step chemical precipitation approach. The microstructure, composition and improved photoelectrochemical properties of the asprepared composites are studied by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photocurrent density, EIS and amperometric i-t curve analysis. It is found that most of In2S3 nanoparticles are deposited on the surfaces of Ag3PO4. The as-prepared Ag3PO4/ In2S3 composite (10 wt%) is selected and investigated by SEM and TEM, which exhibits special morphology consisting of lager size substrate (Ag3PO4), particles and some nanosheets (In2S3). The introduction of In2S3 is effective at improving the charge separation and transfer efficiency of Ag3PO4/In2S3, resulting in an enhancement of photoelectric behavior. The origin of the enhanced photoelectrochemical activity of the In2S3-modified Ag3PO4 may be due to the improved charge separation, photocurrent stability and oriented electrons transport pathways in environment and energy applications.

3 mol% yttria-doped stabilized zirconia (3YSZ) is synthesized by a solvothermal process, and its characteristics are investigated using various methods. Also, the dispersibility of synthesized 3YSZ nanoparticles is observed with the species of surface modifier. The 3YSZ nano sol prepared with an optimum condition is employed in prism coating and its properties are evaluated. The synthesized 3YSZ nanoparticles show a globular shape with about 10 to 20 nm crystallite size. The mixed phases with the nano sol show a high specific surface of 178 m2/g. The prism sheet coated with the 3YSZ nano sol present an excellent refractive index, transmittance, and luminance; refractive index is 1.603, transmittance is 90.2 %, and luminance of coating film is improved by 5.9 % compared to that of the film without 3YSZ nano sol. It is verified that the surface modified 3YSZ is suitable as the prism sheet for optical displays.

Purpose: Recently, with the increasing demand for a evidence-based practice model in the health care area, qualitative meta-synthesis studies that provide a comprehensive understanding of phenomena of interest has increased. This study was conducted to understand the concept of qualitative meta-synthesis and guide the application of appropriate methods. Methods: This study is a literature review to address and analyze concepts and methods used in qualitative meta-synthesis studies. Results: The definition and purpose of qualitative meta-synthesis, philosophical background, procedures and outcomes are described. And the meta-ethnography, which is widely applied, was described. In addition, grounded theory, critical interactive synthesis, and meta-study were briefly introduced. It is also desirable to evaluate the quality of the primary research paper by utilizing evaluation criteria and evaluation tools to select the primary research paper, which also affects the quality of qualitative meta-synthetic studies. It is necessary for the researcher to recognize the epistemological difference in qualitative meta-synthesis, to consider saturation of the primary research paper, and to minimize the decontextualization of the primary research paper. Above all, the creative interpretation of researchers should provide expanded knowledge and insights into the research area. Conclusion: By clarifying the purpose of qualitative meta-synthesis, the researcher should ensure justification for performing qualitative meta-synthesis. Researchers also need to make efforts to ensure methodological transparency in order to overcoming the limitations of qualitative meta-synthesis.

Magnesium hydroxide sulfate hydrate (MHSH) whiskers were synthesized via a hydrothermal reaction by using MgO as the reactant as well as the acid solution. The effects of the H2SO4 amount and reaction time at the same temperature were studied. In general, MHSH whiskers were prepared using MgSO4 in aqueous ammonia. In this work, to reduce the formation of impurities and increase the purity of MHSH, we employed a synthesis technique that did not require the addition of a basic solution. Furthermore, the pH value, which was controlled by the H2SO4 amount, acted as an important factor for the formation of high-purity MHSH. MgO was used as the raw material because it easily reacts in water and forms Mg+ and MgOH+ ions that bind with SO4 2- ions to produce MHSH. Their morphologies and structures were determined using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Molybdenum trioxide (MoO3) is used in various applications including sensors, photocatalysts, and batteries owing to its excellent ionic conductivity and thermal properties. It can also be used as a precursor in the hydrogen reduction process to obtain molybdenum metals. Control of the parameters governing the MoO3 synthesis process is extremely important because the size and shape of MoO3 in the reduction process affect the shape, size, and crystallization of Mo metal. In this study, we fabricated MoO3 nanoparticles using a solution combustion synthesis (SCS) method that utilizes an organic additive, thereby controlling their morphology. The nucleation behavior and particle morphology were confirmed using ultraviolet-visible spectroscopy (UV-vis) and field emission scanning electron microscopy (FE-SEM). The concentration of the precursor (ammonium heptamolybdate tetrahydrate) was adjusted to be 0.1, 0.2, and 0.4 M. Depending on this concentration, different nucleation rates were obtained, thereby resulting in different particle morphologies.

Although flame synthesis promises economic benefit and rapid synthesis of carbon nanotube (CNT), the lack of control and understanding of the effects of flame parameters (e.g., temperature and precursor composition) impose some challenges in modelling and identifying CNT growth region for obtaining better throughput. The present study presents an investigation on the types of carbon precursor that affect CNT growth region on nickel catalyst particles in an ethylene inverse diffusion flame. An established CNT growth rate model that describes physical growth of CNT is utilised to predict CNT length and growth region using empirical inputs of flame temperature and species composition from the literature. Two variations of the model are employed to determine the dominant precursor for CNT growth which are the constant adsorption activation energy (CAAE) model and the varying adsorption activation energy (VAAE) model. The carbon precursors investigated include ethylene, acetylene, and carbon monoxide as base precursors and all possible combinations of the base precursors. In the CAAE model, the activation energy for adsorption of carbon precursor species on catalyst surface E a,1 is held constant whereas in the VAAE model, E a,1 is varied based on the investigated precursor. The sensitivity of the growth rate model is demonstrated by comparing the shifting of predicted growth regions between the CAAE model and the VAAE model where the CAAE model serves as a control case. Midpoint-based and threshold-based techniques are employed within each model to quantify the predicted CNT growth region. Growth region prediction based on the midpoint-VAAE approach demonstrates the importance of acetylene and carbon monoxide to some extent towards CNT growth. Ultimately, the threshold-VAAE model shows that the dominant precursor for CNT growth is the mixture of acetylene and carbon monoxide. A simplified reaction mechanism is proposed to describe the surface chemistry for precursor reactions with nickel catalyst where decomposition of the ethylene fuel source into acetylene and carbon monoxide is accounted for by chemisorption.

This work reports the syntheses of an inexpensive and efficient asphalt-derived mesoporous carbon (AdMC) as an adsorbent. The adsorbent was activated with potassium hydroxide to increase its surface area and then characterized by SEM–EDS, FT-IR, and BET. The adsorption properties of AdMC were evaluated for the adsorptive removal of eleven Poly Aromatic Hydrocarbons (PAHs) and diesel from water samples. The prepared AdMC showed very high surface areas and high micropore volumes equal to 2316 m2/g and 1.2 cm3/g, respectively. Various experimental conditions influencing the adsorption capacity of eleven PAHs and diesel were investigated. At high concentrations, PAHs and diesel solubility in water is very low. Hence, samples were emulsified with a surfactant, and then maximum adsorption capacity was investigated. Adsorption profile of individual PAHs was examined using gas chromatography/mass spectrometry analysis followed by liquid–liquid extraction. Total hydrocarbon removal was studied using a total organic analyzer. Asphalt-derived mesoporous sorbent showed an extreme ability to remove PAHs and diesel (average adsorption capacity of 166 mg/g for individual PAHs and diesel (maximum capacity of 1600 mg/g). The experimental results fitted the Langmuir model with a correlation efficiency of 0.9853. The results obtained for both adsorbents also matched to pseudo-second-order kinetics, suggesting that the adsorption of PAHs and diesel is chemical, monolayer, and homogeneous process.

본 연구에서는 기능성 화장품의 소재로서의 금전초(Lysimachia christinae Hance)의 항산화와 항주름 효과를 조사하였다. 최근 천연물의 주름 개선 개발의 연구가 지속적인 관심을 받고 있어 본 연구를 통해 활성산소종(reactive oxygen species, ROS) 생성과 pro-collagen 합성 및 MMPs의 연관성에 대해 알아보았다. 금전초는 70% 에탄올(LcHE)과 열수(LcHW)로 각각 추출하여 실험을 진행하였다. HaCaT cells에서 LcHE가 LcHW보다 ROS 저해효능이 더 우수하고 세포독성 결과 250 μg/mL 농도 까지 독성을 보이지 않아 LcHE를 선택하여 주름 개선 소재연구를 진행하였다. pro-collagen 합성실험을 통하여 UVB에 의해 감소된 type-1 pro-collagen의 합성 활성을 유의미하게 확인하였다. Western blot 실험을 통하여 피부세포에서 UVB에 의해 유도된 MMPs 중 MMP-1 -3 -9의 증가를 억제함을 확인하였으며, Real time PCR을 통하여 상위단계인 mRNA levels에서도 MMP-1, MMP-2, MMP-3, MMP-9의 mRNA levels가 농도 의존적으로 유의미한 감소를 보여 추출물의 효능을 확인하였다. 위의 실험결과에 따라 UVB에 의한 주름생성과 피부 광노화를 효과적으로 예방할 수 있는 화장품의 천연소재로서의 이용이 기대된다.