In this study, the MoS2 nanoparticles grown on crumpled 3D graphene microball (3D GM–MoS2) was synthesized using a microfluidic droplet generator with thermal evaporation-driven capillary compression and hydrothermal reaction. The morphology and size of 3D GM–MoS2 are controlled by the concentration of nano-sized graphene oxide (GO) and the flow rate of oil phase on the droplet generator. The 3D GM–MoS2 with fully sphere-shape and uniform size (~ 5 μm), and homogeneous growth of MoS2 nanoparticles could be synthesized at the flow rate of the oil phase of 60 μL/min with the optimized GO concentration of 1.0 mg/mL, and ( NH4)2MoS4 concentration of 2.0 mg/mL.

Oil spills into ocean or coastal waters can result in significant damage to the environment via pollution of aquatic ecosystems. Absorbents based on reduced graphene oxide (rGO) foams have the capacity to remove minor or major oil spills. However, conventional chemical synthesis of rGO often uses petrochemical precursors, potentially harmful chemicals, and requires special processing conditions that are expensive to maintain. In this work, an alternative cost-effective and environmentally friendly approach suitable for large-scale production of high-quality rGO directly from used cooking sunflower oil is discussed. Thus, produced flaky graphene structures are effective in absorbing used commercial sunflower oil and engine oil, via monolayer physisorption in the case of used sunflower and engine oils facilitated by van der Waals forces, π–π stacking and hydrophobic interactions, π-cation ( H+) stacking and radical scavenging activities. From adsorption kinetic models, first-order kinetics provides a better fit for used sunflower oil adsorption (R2 = 0.9919) and second-order kinetics provides a better fit for engine oil adsorption (R2 = 0.9823). From intra-particle diffusion model, R2 for USO is 0.9788 and EO is 0.9851, which indicates that both used sunflower and engine oils adsorption processes follow an intra-particle diffusion mechanism. This study confirms that waste-derived rGO could be used for environmental remediation.

Nitrogen-doped carbon dots (N-CDs), derived from the biomass (anthocyanin), are the novel additive to the nanocarbon materials, which is expected to bring a wide spectrum of novel applications. Moreover, metallic oxides are emerging for their unique potential for electrocatalysis. Herein, we report the synthesis of N-CDs for the selective detection of Fe3+ with a limit of detection of 2.57 μM in the range of 5–60 μM using ethylenediamine and H2O2 by a hydrothermal method. The obtained N-CDs displayed a spherical morphology with a particle size range of 2–7 nm and emitted blue luminescence at 394 nm under excitation at 319 nm. Meanwhile, we have demonstrated the fabrication of cost-efficient electrocatalysts for oxygen evolution reaction (OER) in an alkaline medium, employing N-CDs. Owing to the successful incorporation of N-CDs into NiO nanospheres, the resulting N-CDs/NiO with large surface areas, fast charge transfer, and increased conductivity vastly improved the catalytic activity. Remarkably, the optimal of N-CDs/NiO composite requires the overpotential of only 380 mV at a current density of 10 mA cm− 2 and a relatively low Tafel slope of 57.96 mV dec− 1 compared with pure NiO. These results open up a facile route for the application of N-CDs and offer prospects for CD-metal hybrids as high OER catalysts in electrochemical energy devices.

We report the rapid single-step flame synthesis of hydrophobic carbon layers (C-layers) on the surface of stainless-steel (SS) substrates using vaporized biodiesel as the fuel. A co-flow canola methyl ester/air diffusion flame is used to generate a hydrophobic monolayer on the surface of the metal substrate upon its insertion into the reaction zone. Carbon deposition on the surface of the SS substrates varies by changing the SS disk’s position in the post-flame, and by varying its exposure time. The thickness and mass of the flame-formed monolayer varied depending on the substrate’s insertion point into the flame. However, the variation of mass did not significantly impact the C-layer’s uniformity or hydrophobicity. We hypothesize that a small “inner-cone” of the biodiesel flame along with a high soot propensity can result in an ideal medium to form uniform hydrophobic C-layers of unique hierarchical surface structure. This is supported by introducing SS substrates in methane/air flames formed using the same co-flow burner. The hydrophobic property of the carbon deposits was quantified by measuring the contact angle of water droplets placed on the film’s surface. A water droplet drop test was conducted on the flame-formed hydrophobic layers to study their wettability property.

본 연구는 B16F10 melanoma 세포에서 산딸기 잎 추출물(Rubus crataefifolius Leaf Extract, RCLE)의 멜라닌 생성 억제 효과를 확인하고자 수행되었다. α-MSH로 자극한 B16F10 melanoma 세포에서 멜라닌 함량과 tyrosinase 활성, 멜라닌 생성관련 효소들인 TRP-1, TRP-2 및 MITF의 단백질 발현 수준을 조사하였고 이에 대한 RCLE의 효과를 검증하였다. RCLE는 tyrosinase 활성과 멜라닌 생성을 효과적으로 억제하였고 멜라닌 생성 경로에 관여하는 PKA와 CREB의 인산화와 MITF의 발현을 억제하였으며 멜라닌 생성 관련 단백질의 발현을 하향 조절하였다. 이러한 결과는 RCLE가 MITF 발현을 억제하여 α -MSH로 자극된 멜라닌 합성을 억제한다는 것을 보여준다. 따라서 이러한 연구결과는 RCLE가 과도한 멜라닌 생성으로 인한 색소 침착을 완화시킬 수 있는 기능성 화장품 소재로 활용될 수 있음을 시사한다.

안전한 화장품용 방부제에 대한 연구를 위하여 1, 2-octanediol (OD)에 galactose 한 분자가 결합된 1, 2-octanediol galactoside (OD-gal)의 합성을 시도하였다. 이를 위하여, 재조합 대장균의 β-galactosidase (β-gal)를 이용하여 transgalactosylation 반응을 수행하였으며, OD-gal 합성을 확인하기 위하여 mass spectrometry 분석과 NMR (1H- and 13C-) spectroscopy 분석을 실시하였다. 합성 반응물에서 m/z=331.1732의 sodium adduct ion 형태로 OD-gal 분자의 합성을 확인하였고, 정제된 OD-gal의 NMR 분석을 통하여 OD-gal의 1H NMR 스펙트럼에서 OD에 갈락토실화가 되었음을 보여주는 다양한 피크를 확인하였다. 1H NMR 스펙트럼의 다운필드인 δH 4.39 ppm과 δH 3.98~3.55 ppm에서 나타나는 다양한 피크들은 이들이 OD에 갈락토실화가 되었다는 것을 잘 암시하고 있으며, 또한 1H NMR 스펙트럼의 업필드에서 나타나는 δH 1.52~1.26 ppm과 0.89 ppm의 피크는 OD의 CH2 와 CH3 작용기로 부터 나타나는 피크로써 OD가 본 물질에 존재함을 알 수 있었다. 13C NMR 스펙트럼에서는 OD-gal의 알파-아노머와 베타-아노머의 구조에서 기인하는 총 24개의 탄소피크가 나타났고, 각 아노머 마다 14개의 탄소가 존재하는데 이중 δc 31.4, 29.0, 22.3 그리고 13.7 ppm에 보이는 OD 4개의 탄소는 지방족 사슬의 끝부분에 해당하며 화학적 구조의 유사성으로 인하여 탄소 피크가 겹쳐서 나타난 것으로 보인다. 따라서 총 28개의 탄소 피크 중 24개가 나타났다. 마지막으로, 합성된 OD-gal 의 β-gal을 이용한 가수분해 반응을 통하여 OD-gal에 gal이 결합되어 있다는 것을 확인하였다. 이러한 결과를 바탕으로 세포독성이 감소된 첨가물 개발을 기대하고 있으며, 추가적인 후속연구를 진행할 예정이다.

Molecules possessing harmine moiety are reported to exhibit marked fungicidal and bactericidal activities. In this study, various quinozilinium tetrafluoroborate salts were synthesized using acylic and cyclic oxoketene dithioacetals followed by cycloaromatization from Harmine. All of these synthesized compounds were characterized by 1H NMR, 13C NMR, Mass and CHN analysis. This methodology would find wide usage in the preparation of indolo quinozilinium -based library of small molecules useful for medicinal chemistry and in drug discovery.

Here, Zn ferrite is synthesized along with reduced graphene oxide (rGO) by a facile one-step hydrothermal method. The difference between the synthesized nanocomposites with those in other reported work is that the reaction conditions in this work are 160 oC for 12 h. The synthesized products are characterized by field-emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and attenuated total reflection. Further, the adsorption property of rGO–Zn ferrite (rGZF) nanocomposite is studied after confirming its successful synthesis. The adsorption capacity of rGZFs toward rhodamine B (RB) is ˃ 9.3 mg/g, whereas that of bare ZF nanoparticles is 1.8 mg/g in aqueous media. The efficiencies of rGZF and bare ZF to remove RB are 99 % and 20 %, respectively. Employing rGZF, 60 % of RB is decomposed within 5 min. The kinetic study reveals that the adsorption process of removing RB by bare Zn ferrite follows pseudo-firstorder kinetics. However, after zinc ferrite is incorporated with rGO, the kinetics changes to pseudo-second-order. Furthermore, the Langmuir isotherm is accomplished by the adsorption process employing rGZF, indicating that a monolayer adsorption process occurs. The thermodynamic parameters of the process are also calculated.

Strontium lanthanum vanadate La1-xSrxVO3 (LSVO) is a promising anode material for electrochemical devices, especially for solid oxide fuel cells, thanks to its irregular electrical conductivity. However, the known synthesis methods are incapable of producing well-dispersed LSVO nanoparticles (NPs) with homogeneous size distribution, which partly impedes the applicability of the material. Thus, a new approach to synthesize LSVO NPs with such characteristics is of paramount importance. In the present work, we successfully prepare LSVO NPs with a high dispersion degree and homogeneous size distribution via a modified co-precipitation pathway, followed by hydrogen reduction at a temperature as low as 700 oC. The prepared LSVO NPs display uniform sizes in the range of 50 ~ 100 nm and do not contain any secondary phases, according to XRD analysis. The chemical mechanism of reactions that occur to form the LSVO is thoroughly highlighted. The work functions of NPs measured by the UPS analysis are in the 2.13 ~ 3.62 eV range, making the LSVO powders promising for use in thermionic devices. An explanation of the role of Sr substitution in work function values of LSVO is also proposed.

A Y6-xCa1.5xSi11N20O:Ce3+(x=2.5) oxynitride phosphor is synthesized at 1,750 oC in a mixed gas atmosphere of 5% H2 and 95 % N2 by using YN, Ca3N2, Si3N4, and CeO2 as raw material reagents. The crystal structure is a trigonal crystal system that has a P31c (no.159) space group and has lattice parameters of a, b = 9.8876(3), and c = 10.6806(4). This structure is an Er6Si11N20O structure type in which a Y6-xCa1.5xSi11N20O structure is formed by substituting a trivalent Y3+ element and a bivalent Ca2+ element at the position of Er element having an oxidation number of +3. Here, the charge difference caused by different oxidation numbers is balanced by the occupancy of a partially vacant 2c site and an O/N anion ratio in the Er6Si11N20O structure type. The Y6-xCa1.5xSi11N20O:Ce3+ (x = 2.5) phosphor is yellow powder with yellow luminescence; performing Rietveld refinement on the phosphor on the basis of the data obtained by XRD measurement results in the lattice parameters as described above. The Y6-xCa1.5xSi11N20O:Ce3+ (x = 2.5) phosphor has a broad emission band due to Ce3+ as an activator with the center wavelength of 565 nm. This phosphor has a broader emission band than a YAG:Ce3+ phosphor, which is a representative LED phosphor, and thus extends further into the blue and red spectrum ranges. Accordingly, this phosphor is an interesting phosphor that can be used for 1pc-LED with an improved color rendering index.

In this study, (GaN)1-x(ZnO)x solid solution nanoparticles with a high zinc content are prepared by ultrasonic spray pyrolysis and subsequent nitridation. The structure and morphology of the samples are investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The characterization results show a phase transition from the Zn and Ga-based oxides (ZnO or ZnGa2O4) to a (GaN)1-x (ZnO)x solid solution under an NH3 atmosphere. The effect of the precursor solution concentration and nitridation temperature on the final products are systematically investigated to obtain (GaN)1-x(ZnO)x nanoparticles with a high Zn concentration. It is confirmed that the powder synthesized from the solution in which the ratio of Zn and Ga was set to 0.8:0.2, as the initial precursor composition was composed of about 0.8-mole fraction of Zn, similar to the initially set one, through nitriding treatment at 700oC. Besides, the synthesized nanoparticles exhibited the typical XRD pattern of (GaN)1-x(ZnO)x, and a strong absorption of visible light with a bandgap energy of approximately 2.78 eV, confirming their potential use as a hydrogen production photocatalyst.

Phenylethanol (PhE)에서 야기되는 피부 부작용 문제를 극복하기 위한 대안으로 phenylethanol galactoside (PhE-gal)에 대하여 연구하였다. 그 중에서도 대장균 효소 β-galalactosidase (β-gal)을 이용하여 PhE로부터 PhE-gal를 합성하는 반응의 최적 조건에 대하여 조사하였다. 그리고, 용매 분획연구를 수행하여 PhE-gal의 특성도 조사하였다. 반응조건 중에서 반응액의 β-gal 농도, PhE 농도, 반응액의 pH, 그리고 온도에 대하여 조사한 결과, 최적 β-gal의 농도는 0.45 U/ml, 최적 반응물 PhE의 농도는 1.0%, 최적 반응액의 pH는 8.0, 최적 반응온도는 40℃ 였다. 그리고, 최적 반응조건에서 48 시간까지의 반응을 관찰하였는데, 약 81.9 mM의 PhE로부터 약 47.4 mM의 PhE-gal이 합성되었고, PhE로부터 PhE-gal로의 전환수율은 약 57.9% 정도였다. 또한, PhE와 PhE-gal이 포함된 반응물을 용매 EA와 MC로 분획한 결과, 물 층으로 대부분의 PhE-gal이 분획 되었고, 용매 층으로는 PhE가 분획 되었다. 그러나, 물 층으로의 PhE-gal의 분획이 용매 MC를 사용할 때, 더 분명하고 명확하게 나타났으며, 용매 EA를 이용한 분획에서는 명확히 물 층으로 PhE-gal이 분획 되지 않았다. 앞으로, PhE-gal을 화장품에 사용할 수 있는 첨가물(방부제)로 개발하기 위한 후속연구를 계속 진행할 예정이다.

In this study, we report a controlled one-pot green synthesis of multiwalled carbon nanotubes (MWCNTs) via pyrolysis of sustainable agriculture waste (chickpea peel) at 400 °C in aqueous medium. These MWCNTs demonstrated 7.0 nm diameter, 0.28 nm graphitic spacing with carbonyl, hydroxyl, and carboxylic acid functionality. The D band (presence of sp3 defects) and G band ( E2g mode of graphite) at 1350 cm−1 and 1580 cm−1 originated in Raman spectrum, respectively. The prepared MWCNTs showed blue fluorescence with 10% fluorescence quantum yield in aqueous medium. The MWCNTs showed triple exponential decay characteristics with an average fluorescence lifetime of 4.7 ns. The synthesized MWCNTs revealed a consistent fluorescence in the cytoplasm of 22RV1 human prostate carcinoma cell line without exerting any sign of cytotoxicity. The MWCNTs also exhibited remarkable cytocompatibility in human immortalized prostate epithelial RWPE1 cells.