NANOTECHNOLOGY
·
2019
·Vol. 30
·期 26
·265704
·
IF 3.399
Yujuan Fan,Xingfa Yang,Chaoshun Yin,Chenao Ma,Xingping Zhou
In the past decade, hydrophobic fluorescent carbon dots (OCDs) have received little attention, and its potential application and light transition mechanism is seldom explored. Here we report a novel one-step approach for synthesizing blue- and green-emitting hydrophobic fluorescent carbon dots (OCDb and OCDg) by calcinating with the uses of citric acid and hexadecylamine as initial reactants. The optimal conditions for preparing OCDb and OCDg were obtained by using the Taguchi L25 (35) orthogonal array. The highest quantum yield and product yield of OCDs reached 80.2% and 57.1%, respectively, larger than those from most of all the known reports. The fluorescent stability of OCDb and OCDg was excellent under UV irradiation (30 W) for days. The luminescent color of OCDs showed a great dependence on reaction conditions. It is easier to get OCDg via a reaction kept at a high temperature for a long time. The optical transition mechanism was studied for the two kinds of color OCDs, and therefore proposed in combination with their optical properties and surface groups. The reason for light transition is probably related to an appropriate critical ratio and surface density of the C=O and N–H bond in the surface structure of the product. For the OCDg, the concentration matching ratio of N–H and C=O bonds in the surface structure of the green-emitting product is approximately between d/2 and 3d/2, where d is a fixed constant. Lower than or higher than this critical ratio range, the product emits blue light. Based on their high fluorescence quantum efficiency and the advantages mentioned above, these OCDs were then respectively used for preparing hydrophobic fluorescent carbon dot-loading liposomes and acrylate films, both exhibiting a perfect performance with no fluorescence quenching.
研究领域:
化学
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材料科学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Yicheng Ye,Qiaohong Zhang,Guoying Weng,Zhuwei Zhu,Zhenguo Lyu,Chen Chen
The species and amount of the surface groups are closely related with the catalytic performance for a heterogeneous catalyst. High content of alkylamino (50 mol%) and n -propyl (15 mol%) were simultaneously introduced onto the surface of SiO 2 nanospheres with a one step reverse-phase microemulsion method. Accompanying the formation of plenty of surface nano-bulges, a high ratio (86.5 %) of the silicon species were exposed on the surface of this novel material. Abundant of surface groups including Si-NH 2 (5.5 mmol g −1 ), Si-C 3 H 7 (1.7 mmol g −1 ), and Si-OH (6.1 mmol g −1 ) coexisted on the surface enabled this novel material to be a very efficient catalyst for the Aldol condensation reaction between benzaldehyde and n -heptanal. Higher content of alkylamino supplied more catalytic sites. Proper ratio of silanol-to-alkylamino (a little higher than 1) facilitated the adsorption of the substrate molecules and strengthened the cooperation between alkylamino and silanol. Surface hydrophobic modification with n -propyl further facilitated the adsorption of the substrate molecules at the presence of the byproduct of water. Conversion of 99 % was successfully obtained at a lower temperature (90 °C) and in a very short time of 25 min with the present material being used as the catalyst. In some other Aldol condensation reactions, the present catalyst NH 2 -SiO 2 -C 3 H 7 also showed excellent catalytic performance.
研究领域:
材料化学
·
催化化学
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产品关联
DOI
高影响因子
ChemistryOpen
·
2019
·Vol. 8
·期 1
·87-96
·
IF 2.205
Chunshan Lu,Xuejie Zhang,Yani Qi,Haoke Ji,Qianwen Zhu,Hao Wang,Yebin Zhou,Zhenlong Feng,Xiaonian Li
Graphical On the surface : The surface-group-oriented nitrogen-doping strategy for activated carbon-supported Pd catalysts and the potential selective hydrogenation mechanism of p-chloronitrobenzene are presented. A nitrogen-carbon framework with the thickness of several molecules was fabricated through a straightforward nitrogen-doping strategy, in which specially designed surface-oxygen-containing groups (SOGs) first introduced onto the porous carbon support were used to guide the generation of a surface-nitrogen-containing structure through condensation reactions between SOGs and the amidogen group of organic amines under hydrothermal conditions. The results indicate that different kinds of SOGs generate different types and abundances of N species. The CO-releasing groups are apt to form a high proportion of amino groups, whereas the CO 2 -releasing groups, especially carboxyl and lactones, are mainly transformed into pyrrolic-type nitrogen. In the framework with dominant pyrrolic-type nitrogen, an electron-rich Pd activated site composed of Pd, pyrrolic-type N and C is built, in which electron transfer occurs from N to C and Pd atoms. This activated site contributes to the formation of electron-rich activated hydrogen and desorption of p-chloroaniline, which work together to achieve the superior selectivity about 99.90 % of p-chloroaniline and the excellent reusable performance. This strategy not only provides low-cost, nitrogen-doped carbon materials, but also develops a new method for the fabrication of different kinds of nitrogen species structures.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 9
·6459-6470
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IF 2.993
Feng Zhibiao,Li Zeliang,Zhang Xingwei,Xu Guoqiang,Zhou Nan
Herein, we report the synthesis of carbon dots (CDs) with two characterized absorption bands but without excitation wavelength-dependent fluorescence via a one-step hydrothermal method. The structure of CDs was characterized using X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, Fourier transform infrared, and UV–Vis spectroscopy. The structure and photoluminescence of CDs vary significantly with different raw materials and preparation methods, and the mechanism of luminescence is not clear yet. Hence, we studied the luminescence mechanism behind two characterized absorption bands of CDs using fluorescence quenching method with ninhydrin and several ions as quenchers. The influence of the surface groups of CDs on its photoluminescence properties was also discussed. Ninhydrin and a variety of other ions exhibited different quenching effects on the fluorescence emissions which obtained at the two absorption bands of CDs. Combining with the structure characterization results, it can be concluded that the emission wavelength is mainly determined by the carbon core, while the excitation wavelength is determined by the surface nitrogen-containing groups. (The excitation at 234 nm might be due to the Schiff base structure, while the excitation at 345 nm was mainly due to the amide structure.) Furthermore, based on the interaction of NO 2 − with the surface nitrogen-containing groups of CDs, a quantitative detection method of NO 2 − using CDs was proposed in our study. CDs exhibited high selectivity for NO 2 − at pH 1.6 with good linearity to NO 2 − concentration in the range of 1–10 μM.
研究领域:
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Bingtian Huang,Qing Sun,Liancheng Bing,Dezhi Han,Guangjian Wang,Fang Wang
Activated carbon (AC) treated with nitric acid (HNO3) and hydrogen peroxide (H2O2) was prepared for the study of the effect of oxygen-containing functional groups on the adsorptive removal of organochlorines from oil. The adsorption performance and physicochemical properties of the adsorbents were tested and analyzed. The results show that the HNO3–H2O2 comodified AC (NPAC) presented the best adsorptive efficiency, especially for the removal of aromatic chlorides. It has been found that the surface chemical groups and the physical texture of AC play major roles in the adsorption performance of organic chlorides. The potential of activated carbon (NPAC) treated with nitric acid and hydrogen peroxide in removing organic chlorine from oil was comprehensively evaluated through experimental data combined with mathematical models of kinetics and equilibrium. The adsorption process conforms to the Freundlich isotherm equation, which proves that there is multilayer adsorption in the adsorption process, and 1,2-dichlorobenzene (DCB) is more easily adsorbed by modified AC. The kinetic results indicate that there is chemical adsorption during the adsorption process, and the diffusion process of organic chlorides in AC is influenced by several factors.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2019
·
IF 4.85
Guohui Li,Kun Jiang,Sher Zaman,Jinnan Xuan,Zhiqiang Wang,Fengxia Geng
Tuning the feature sizes and surface moiety groups of a two-dimensional (2D) sheet material has been regarded as the most effective strategy for achieving desired physical and chemical properties. The newly emerging transition-metal carbide or nitride sheets, generally referred to as MXenes, are of interest to the research community owing to their versatile behavior. While the chemical stability of MXenes is of pivotal importance to their real applications, a systematic study of examining the effect of their surface and lateral size on the resulting chemical stability is still lacking. Herein, by systematically varying the synthesis parameters, we obtained both regular and ultrasmall Ti3C2 sheets with different surfaces, namely, Al oxyanions or OH/F. To investigate the chemical stability and sustainability of each Ti3C2 sheet in an oxidizing environment, including an ambient atmosphere and a H2O2 medium, the evolution of phase, morphology, and optical behavior was carefully studied. The sheets covered with Al oxyanions had greater structural stability than those covered with the other species considered in this study, which may be due to the Al oxyanions acting like a shield and passivating the surface in the oxidizing atmosphere. Regarding the effect of feature size, thinner sheets or those with smaller lateral dimensions showed improved oxidation resistance, which could be due to the difficulty encountered in the structural recrystallization from Ti3C2 to oxidized product TiO2. This study provides a deeper understanding of MXenes and a method to efficiently engineer structures with desired performances.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 32
·期 2
·2106828
·
IF 18.808
Yuanyuan Yang,Zhenhao Qiu,Guoying Weng,Huibin Wang,Yanshuo Li,Benhan Fan,Xiu Bai,Qiaohong Zhang,Chen Chen
Amphiphilic silica is synthesized with the simultaneous introduction of two kinds of polar and weakly polar organic groups on its surface using a one-step reverse-phase microemulsion method. The obtained materials present as nanospheres with a size of ≈100 nm. A high percentage (≈80%) of silicon species can be exposed and the amount of surface Si OH increased by above 50% with the introduction of organic groups. Plenty of groups, including polar groups (3-aminopropyl and hydroxyl) and weakly polar group (n-propyl) coexisting on the surface, enable the material to show amphiphilicity. This amphiphilic material can show an excellent property for the removal of various organic dyes from the aqueous solution, and the maximum adsorption capacity of Congo Red, Acid Blue 25, Reactive Blue 19, and Reactive Black 5 can reach 2453.1, 1157.7, 964.6, and 916.9 mg g −1 , respectively. Good reusability is also realized for the present amphiphilic material, which can be reused for at least three times. The reported work provides a successful example to prove that the surface hydrophilicity and lipophilicity can be simultaneously improved just through a simple introduction of certain organic groups, and then realize efficient removal of dyes from the polluted water.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INORGANIC BIOCHEMISTRY
·
2020
·
IF 3.212
Dan Zhao,Xuemei Liu,Rui Zhang,Xincai Xiao,Jun Li
The preparation and performance of doped antibacterial carbon dots (CDs) have been the research hotspot. In this paper, we report the preparation of two blue light-emitting silver-doped CDs, CD-1 and CD-2, through one- and two-step routes, respectively, by using polyethyleneimine , citric acid , and AgNO 3 as raw materials. Both CDs exhibited excellent and broad-spectrum activity against gram-positive bacteria, gram-negative bacteria, and fungi. We compared the emission wavelength , surface group, particle size, chargeability, and element content of the two CDs through various characterization methods. CD-2 exhibiting longer emission wavelength, larger particle size, and higher silver content displayed higher antibacterial activity against microorganisms than CD-1. On the other hand, CDs exhibited varying antibacterial properties against different microorganisms because of differences in the cell wall structure of gram-positive bacteria (peptidoglycan), gram-negative bacteria (lipopolysaccharides), and fungi (chitin). Based on scanning electron microscopy observations, circular dichroism spectroscopy and agarose gel electrophoresis , we speculate that CDs exert antibacterial activity mainly through membrane disruption and their effect on intracellular DNA and proteins. At the same time, CDs have multicolor imaging capabilities of Staphylococcus aureus . The antibacterial activity and versatility of bioimaging make them more potential antibacterial agents than traditional agents.
研究领域:
材料科学
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微生物学
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2022
·
IF 5.304
Xiang Li,Xiu Yan,Conghui Wang,Yunxiao Ma,Yi Jiang,Rongjing Wang,Dongyang Shi,Zhongjian Li,Guifen Zhu,Bing Tan
Red emission carbon dots (R-CDs) have great potential applications in optical and electronic devices, but few studies have focused on synthesizing R-CDs with tunable functional groups. In this study, p-phenylenediamine and hydroquinone were selected as precursors with specific hybridized carbon structures for synthesizing R-CDs with tunable functional groups by hydrothermal method. The proportion of precursors in the reaction system were adjusted to successfully synthesize R-CDs with various contents of oxygen and amino groups. Experimental results showed that the fluorescence of the R-CDs was effectively quenched by Fe 3+ through the formation of R-CDs/Fe 3+ complex. The fluorescence quenching ability of Fe 3+ for R-CDs with different N/O ratios were also investigated. The fluorescence quenching efficiency of Fe 3+ for R-CDs increased with the oxygen content of the R-CDs. By selecting R-CDs with oxygen-containing surface groups (R-O-CDs) as nanoprobe, an “on–off-on” fluorescent sensor has been developed for dual-detection of Fe 3+ and pyrophosphate (PPi). A detection limit of 0.527 μM for Fe 3+ and 0.24 μM for PPi were achieved. The as-developed R-O-CDs/Fe 3+ nanoprobe was also successfully used to detect Fe 3+ and PPi in real samples. Furthermore, an IMPLICATION logic gate was designed.
研究领域:
材料科学
·
分析化学
✓ 已验证
DOI
高影响因子
WATER AND ENVIRONMENT JOURNAL
·
2022
·Vol. 37
·期 2
·316-325
·
IF 1.977
Bo Xing,Chaoting Fu,Guo Yang,Xiang Song,Xingyong Liu,Xiaonan Liu,Qiang Zhou,Zhongcai Pan,Junjie You,Yuling Ye
N,S-codoped mesoporous carbon (S/NMC) as an effective catalyst toward the catalytic persulfate oxidation of sulfamethazine (SMZ) was fabricated conveniently using vinasse as the C/N source, Na 2 S as the S precursor and nano-SiO 2 as the template, respectively. The effect of S precursor dosage on the textural properties and surface chemistry of S/NMCs were characterized by N 2 adsorption/desorption, Raman spectra, X-ray diffractometer (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). It was found that more S precursor dosage presented an enhanced SMZ degradation performance due to the significant role of more S precursor dosage: (i) larger specific surface area and (ii) more active surface groups including pyridine N, graphite N, quinone-like O and thiophene-like S. In addition, quenching experiments showed that free radical and nonradical oxidation processes are the main processes of SMZ degradation. The findings provided a new idea for the resource utilization of vinasse and the development of catalytic persulfate oxidation of organic pollution.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Ke Yao,Jian Wei,Peidong Hong,Yulian Li,Chao Xie,Zijian Wu,Kaisheng Zhang,Minqiang Li,Junyong He,Lingtao Kong
Iron-mediated activation of peroxymonosulfate (PMS) had long been of great interest for the effective oxidation of micropollutants. However, how the chemical environment of iron oxides influence active species formation in heterogeneous Fenton processes was poorly understood. Herein, Fe 3 O 4 -X nanospheres (X = –NH 2 , –COOH) were synthesized for coordination chemical environment regulation. The DFT calculation showed the models of Fe 3 O 4 -X modified by –NH 2 and –COOH in four-coordination and six-coordination environments. Among them, Fe 3 O 4 -COOH in four-coordination environment had the lowest formation energy and highest adsorption energy combined with PMS, with a most stable system. In the adsorption model of four-coordination Fe 3 O 4 -COOH, the d-orbitals and s-orbitals energy levels of Fe atoms underwent drastic changes compared with those before adsorption, H atoms on the carboxyl group and O atoms on the PMS formed a new HO – that attached to Fe atoms, with a strong coupling between them. The simulation results confirmed the proposed activation mechanism of Fe 3 O 4 -COOH activating PMS to generate SO 4 ·- and HO – , and then partial SO 4 ·- reacted with HO – to generate ·OH, and finally the two radicals attacked tetracycline (TC) together. In Fe 3 O 4 -COOH/PMS system, Fe 3 O 4 -COOH/PMS system can convert more Fe 2+ into Fe 3+ , which also means that more Fe 2+ reacts with PMS to produce Fe 3+ and SO 4 ·- . The TC degradation efficiency of the Fe 3 O 4 -COOH/PMS system was 93%, higher than that of the Fe 3 O 4 -NH 2 /PMS system after 30 min of reaction. Consequently, this work contributes to the mechanistic insight into active species regulation during Fenton-like processes by manipulating surface groups.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2022
·
IF 6.206
Yufeng Liang,Lipeng Wang,Yongping Bai,Haiyan Qian,Huifang Xu,Yu Wang
UV-cured releasing agent is a new type of anti-fouling coatings, which must meet needs of the development in the pressure-sensitive adhesive industry, but also in line with modern environmentally friendly demands. With a step-by-step method, a multi-functional photosensitive silicone modified polyurethane releasing agent was synthesized using a hydroxyalkylsiloxane, toluene diisocyanate, and pentaerythritol triacrylate, carrying out by UV initiating technique to prepare the releasing films. The infrared spectrum and the nuclear magnetic resonance spectrum were used to analyze a molecular structure of the releasing agent. Peel strength tests and morphological tests were used to characterize the application capabilities of the releasing films. X-ray photoelectron spectroscopy and other techniques were simulated the migration of the surface group of the releasing films during the pressure sensitive adhesive adherence. The results showed that the excessive soft segment silicone chain reduced crosslink density, thereby reducing the residual performance, while the excessive polar group density would simultaneously reduce the releasing performance and residual performance. This conclusion reveals the releasing mechanism of the UV-cured releasing agent, and provides an important guiding significance for the molecular design and product development of the new type of releasing agent.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）