JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2016
·
IF 3.652
Shun Zhou,Qing He,Xiaofeng Wang,Min Ning,Ying Yang,Yingbo Xu,Yaping Zhang,Peng Zou,Zhenfeng Tian,Kaibo Chen,Hua Wang,Shike She
The effects of exogenous potassium salts on the thermal degradation of flue-cured tobacco were investigated using thermogravimetric analysis (TGA), surface area/porosity measurements (SAPM), real-time fourier transform infrared (RT-FTIR), and thermogravimetric/Fourier transform infrared spectrometry (TG-FTIR), respectively. TGA analysis showed that potassium salts accelerated tobacco’s degradation at around 150–350 °C, but improved the thermal stability of char residue at high temperature range. The porous texture analysis displayed that potassium salts reduced the pore volume and surface area of tobacco pyrolysis residues. Further study using RT-FTIR illustrated that there was a positive catalysis of potassium salts with C O, O H and C O bonds at different temperature ranges, but a protective effect was given to C H bond, C C bond and aromatic moieties except for the accelerating degradation of C H by the oxidation effect of KNO 3 . The evolution comparison of their gaseous products manifested that potassium salts cut down the emission of CO 2 , H 2 O, CO, aldehydes and alkanes, but enhanced the release of carbonyl compounds, anhydrides and alcohols at around 150–350 °C. Above 350 °C, the potassium salt-containing samples exhibited a gentle escape process for both the oxygen-bearing molecules (CO 2 , H 2 O and CO) and oxygen-free species (alkanes, methane and unsaturated compounds) in comparison with their quick emission for the virgin samples.
研究领域:
烟草科学
·
热化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Yingdong Zhang,Lin Wang,Zhiwei Yang,Dongmei Yue
Janus particles, heterogeneous bifacial particles, have gained significant interest in materials science and chemical engineering. Nanoscale fabrication of these particles poses notable challenges. Although mature techniques exist for creating Janus particles from inorganic and polymeric materials, similar advancements in carbon dots (CDs) remain unreported. This paper introduces a novel approach using a liquid–liquid interface method to specifically modify CDs suspended at the biphasic interface, resulting in the formation of carbon dots with a unique Janus-type surface distribution (J-CDs). The surface structure was analyzed using transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, elemental analysis and 13 C NMR spectroscopy. By correlating their fluorescence properties with time-dependent density functional theory (TDDFT) calculations, the relationship between the fluorescent characteristics of J-CDs and their asymmetric Janus surface structures was established, further confirming their unique Janus configuration. Water contact angle tests showed that J-CDs exhibit hydrophilic and hydrophobic properties that differ distinctly from those of traditional amphiphilic CDs when suspended in various solvents and dried on a silicon substrate, underscoring their novel structure. Enhanced surface properties were demonstrated through the stabilization of Pickering emulsions and fabrication of polystyrene microspheres, showcasing the potential of J-CDs to modulate surface characteristics for diverse applications.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
DESALINATION
·
2015
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IF 3.756
Lei Wang,Danxi Huang,Xudong Wang,Xiaorong Meng,Yongtao Lv,Xin Wang,Rui Miao
To obtain a high-performance polyvinylidene fluoride (PVDF) membrane, low-temperature thermally induced phase separation (LT-TIPS) was employed to prepare microporous flat PVDF membranes and hollow-fiber membranes using diluent mixtures of triethylphosphate and diethylene glycol monoethyl ether acetate. The membrane morphology was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that thermally induced phase separation (TIPS) played a more important role than nonsolvent-induced phase separation (NIPS) in determining the cross-sectional morphology of the membranes, and the surface structure was mainly affected by NIPS in a low-temperature (0 °C) coagulation bath . By increasing the temperature of the coagulation bath, different structures of membranes, such as spherulites and cellular and sponge structures, were observed. It is believed that the formation mechanism of these membranes depended on a combined NIPS and TIPS process. Wide-angle X-ray diffraction (XRD) analysis indicated that PVDF crystallized into an α-phase crystal structure for all the membranes tested. In addition, the porosity, tensile strength and filtration performance of the flat membranes were measured. On the basis of the above results, a hollow fiber membrane with highly interconnected pores and high porosity could be prepared employing LT-TIPS.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2022
·Vol. 33
·期 21
·215705
·
IF 3.953
Zhen Mao,Hui Li,Na Gan,Zili Suo,Huan Zhang,Qiang Zhao
Fixed carbon source and different dopants are mainly used to study the effect of heteroatoms on the structure and properties of carbon dots (CDs). As reactants, some dopants with conjugated structure and high nitrogen content may have important contributions to the structure and properties of doped CDs in addition to providing heteroatoms. Herein, to study the effect of fixed dopant on the structure and properties of CDs, three different CDs were synthesized using nicotinamide (NAA) and three common α-hydroxy acids (4–5 carbon atoms), and the optimal conditions were determined by orthogonal experimentation. Transmission electron microscopic micrographs showed that the average size of CDs based on nicotinamide are relatively large, up to 19.40 nm. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy demonstrated that these CDs have graphite nitrogen and several functional group structures. Ultraviolet–visible absorption spectra, fluorescence emission spectra, and fluorescence lifetime illustrated that these CDs have similar emission centers (460–470 nm) and fluorescence processes. The influence of carbon source on the surface structure of CDs was determined by systematically analyzing the response of these CDs in different pH ranges. DFT calculations revealed the distribution characteristics of the electrons in the excited state at the HOMO and LUMO energy levels of CDs. All the above characterizations and calculations proved that NAA is a desirable dopant with an important contribution to the structure and properties of CDs.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Fanfan Liu,Aiguo Zhou,Jinfeng Chen,Jin Jia,Weijia Zhou,Libo Wang,Qianku Hu
Here we reported the preparation of Ti 3 C 2 MXene and Ti 2 C MXene by etching Ti 3 AlC 2 and Ti 2 AlC with various fluoride salts in hydrochloric acid (HCl), including lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), and ammonium fluoride (NH 4 F). As-prepared Ti 2 C was further delaminated by urea, dimethylsulfoxide or ammonium hydroxide. Based on theoretical calculation and XPS results, the type of positive ions (Li + , Na + , K + , or NH 4 + ) in etchant solution affect the surface structure of prepared MXene, which, in turn, affects the methane adsorption properties of MXene. The highest methane adsorption capacity is 8.5 cm 3 /g for Ti 3 C 2 and 11.6 cm 3 /g for Ti 2 C. MXenes made from LiF and NH 4 F can absorb methane under high pressure and can keep methane under normal pressure, these MXenes may have important application on capturing methane or other hazardous gas molecules. MXenes made from NaF and KF can absorb methane under high pressure and release methane under low pressure. They can have important application in the adsorb storage of nature gas.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2014
·Vol. 16
·期 47
·10750-10753
·
IF 3.858
Lingqing Dong,Kui Cheng,Wenjian Weng,Weiqiang Han
In this communication, strontium titanate (SrTiO3) nanocrystals with tailored surface structures have been synthesized by the hydrothermal method using potassium hydroxide (KOH) and lithium hydroxide (LiOH) as the mineralization agents. The results show that the surface structure adjusted by introducing different mineralization agents dictates not only the corresponding size and shape but also the dielectric properties of the obtained SrTiO3 nanocrystals.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2019
·
IF 5.589
Tingming Ye,Weixiao Qi,Xiaoqiang An,Huijuan Liu,Jiuhui Qu
Anthraquinone (AQ), a common oxygenated polycyclic aromatic hydrocarbon (PAH) in the water environment, often occurs with higher concentrations than its parent anthracene as it is the dominant intermediate from anthracene during both wastewater treatment and transformation in natural waters. During the elimination of PAHs and their intermediates, the water matrix often induces positive or negative effects. In this paper, photocatalytic degradation of AQ in the presence of inorganic ions (NO 3 − , HCO 3 − , Fe 3+ ) and organic matter (humic acid) was studied with {101} and {010}-TiO 2 as sunlight-driven photocatalysts. Meanwhile, the effect of dissolved oxygen (DO) on photocatalytic degradation of AQ was evaluated. The results showed that NO 3 − had a slight suppressing effect, while HCO 3 – and Fe 3+ promoted the photocatalytic activity due to formation of new oxidizers (CO 3 − and H 2 O 2 ). Interestingly, HA could envelope {101}-TiO 2 to inhibit photodegradation ; however, it had almost no effect on {010}-TiO 2 due to the different surface structures and properties. High dissolved oxygen content in water could markedly promote the photodegradation of AQ. This was consistent with the results of scavenging experiments, which demonstrated that O 2 – and h + played more important roles than OH did. A small amount of benzene was detected as an intermediate product of AQ by LC-QTOF-MS analysis. Hopefully, this work can contribute to the understanding of the potential of water remediation by faceted photocatalysts.
研究领域:
环境科学
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化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2020
·
IF 4.189
Zilong Zhang,Yaoyi He,Yangyang Lv,Lei Zhang,Xiqiao Chen,Zhuang Wu,Yanhong Zou
In this paper, two-dimensional Ti3C2Tx-MXenes with abundant defects and functional groups as well as appropriate conductivity were successfully synthesized by acid treatment at room temperature. The relationship between the surface structure and its electromagnetic wave absorption ability was systematically studied by changing etching time and heat treatment. Benefiting from the conduction loss and strong polarization relaxation around the abundant interface areas in the two-dimensional layered structure, the Ti3C2Tx Mxene composite possesses excellent electromagnetic absorption performance. Remarkably, optimized Ti3C2Tx exhibits extremely strong absorption with a minimum reflection coefficient of −65 dB, and the qualified absorbing bandwidth is up to 5 GHz. Furthermore, the ultrathin matching thickness of the Ti3C2Tx Mxene composite is 1.4 mm. The prominent absorbing performance outperforms most recently reported two-dimensional carbon materials for microwave absorption.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Hui Li,Nana Wang,Tangfu Xiao,Xiangting Zhang,Jianqiao Wang,Jinfeng Tang,Qingnan Kong,Chuanbin Fu,Huabang Quan
Arsenic (As) is a problematic pollutant that can cause cancer and other chronic diseases due to its potential toxicity. Iron (oxyhydr)oxides can readily sorb As and play important roles in the geochemical cycle of As. Attention has mainly been given to the affinity and mechanism of As sorption by synthetic pure iron (oxyhydr)oxides, and little is known about the relationship between As behavior and multicomponent secondary iron minerals (SIMs) naturally formed in acid mine drainage (AMD). To investigate this relationship, we performed sorption kinetics, isotherm and competitive sorption experiments to investigate As(V) sorption behaviors on naturally formed SIMs harvested from different runoff zones of an abandoned coal mine. Several spectroscopic analyses were used to evaluate the structural and component changes and phase transformation. Three environmental SIMs formed at nascent (n-SIM), transient ( t -SIM) and mature ( m -SIM) stages were determined to be similar in the element components of Fe, S and O but different in structure. As(V) sorption behaviors on these environmental SIMs followed a pseudo-second-order kinetic model, and the sorption extent followed the sequence of n-SIM > t -SIM > m -SIM. As(V) sorption is not significantly influenced by Na + /Ca 2+ concentration or ionic strength except for that of PO 4 3− , and it slightly decreases as the Cr(Ⅲ) concentration increases but increases with increasing Sb(Ⅲ)/(V) concentration. The results of spectral analyses indicate that As(V) immobilization mainly depends on exchange with SO 4 2− and surface complexation, along with the phase transformation of schwertmannite/jarosite to goethite and other phases. These findings are helpful for better understanding the geochemical behaviors of As(V) associated with environmental SIMs.
研究领域:
环境科学
·
地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2025
·
IF 4.1
Shao-Hui Huang,Jie Wu,Jing Chi,Tai-Shen Yang,Jin-Chao Cao
Selective dissolution is an effective strategy to improve the catalytic performance. This method was used to regulate the surface structure of SmMn 2 O 5 through HNO 3 acidification to promote its oxygen reduction reaction (ORR) performance. The relationship between the structures and ORR performances of SmMn 2 O 5 acidified by different concentrations of HNO 3 (5-8 M) was investigated. HNO 3 can selectively dissolve part of Sm, which reduces Sm/Mn ratio, and increases Mn 4+ /Mn 3+ and surface adsorbed oxygen/lattice oxygen ratios on the catalyst surface. Especially, the increase of Mn 4+ content optimizes the adsorption of oxygen-containing intermediates on Mn 3+ active sites and enhances the ORR activity. When treated with 7 M HNO 3 for 10 h, the acidified SmMn 2 O 5 surface has suitable Mn 4+ /Mn 3+ ratio, exhibiting excellent ORR performance. Compared with SmMn 2 O 5 , the half-wave potential of the acidified SmMn 2 O 5 increases from 0.80 V to 0.83 V, and the diffusion-limited current density improves from 3.44 mA·cm −2 to 4.76 mA·cm −2 . Additionally, the synergistic catalytic mechanism of Mn 4+ with Mn 3+ active sites was well discussed.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Qian Guo,Ziyun Su,Dong Xiang,Beirong Yu,Di Wang,Youjun Fan,Fuqin Zheng,Wei Chen
As model catalysts, it is necessary to study the relationship between the structure and properties of ultra-small metal nanoclusters (MNCs) and to reduce their steric hindrance as much as possible, e.g. preparing ultrasmall MNCs protected by ultra-short ligands. However, it is challenging to attain various MNCs with the same cores but different surface stabilizing ligands. Additionally, shortening the chains of protecting ligands will lead to larger MNC cores. Here, four different Pd NCs (Pd 6 (SC 4 H 9 ) 12 , Pd 6 (SC 8 H 17 ) 12 , Pd 6 (SC 6 ( C 2 )H 17 ) 12 and Pd 6 (SC 6 H 13 ) 12 ) were successfully synthesized by a slow synthesis process. All these clusters consist of six Pd atoms and are stabilized by 12 thiols with different chain lengths and steric hindrance. The catalytic properties of the as-prepared Pd 6 NCs were evaluated using the catalytic reduction of p-nitroaniline to p-phenylenediamine as a model reaction. The outcomes indicated that shortening the chain length of the protecting thiols could enhance the catalytic activity of the Pd 6 NCs. Notably, stable and active ultra-small Pd 6 clusters stabilized by ultra-short ligands (HSC 4 H 9 ) were successfully synthesized. Although the performance of Pd 6 (SC 4 H 9 ) 12 clusters protected by the ultra-short thiols is lower than that of commercial palladium on carbon (Pd/C), they display higher stability. Interestingly, the activity of Pd 6 NCs protected by ethyl-branched alkane thiols is also better than that of Pd 6 NCs protected by the alkane thiol ligands with the same chain length or the same number of carbon numbers. This work provides clear evidence that the catalytic activity of atomically precise MNCs can be controlled by regulating the surface stabilizing ligands.
研究领域:
化学
·
材料科学
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2024
·
IF 6.5
Qian Liu,Jianbing Cui,Tatsuo Kaneko,Weifu Dong,Mingqing Chen,Jing Luo,Dongjian Shi
The inevitable presence of fog causes a loss of light transmission in optical materials and leads to many unacceptable and serious consequences. A promising strategy for avoiding fog is to modulate the wettability of the material surface and further change the formed way of droplets. Although many works achieved high antifogging coatings, they are lack of the long-lasting antifogging at varied conditions. In this work, a high adhesion strength and persistent antifogging capability hydrophilic coating is obtained by utilizing silane coupling agents containing double bonds such as triethoxyvinylsilane (A151) and 3-(trimethoxysilyl)propyl methacrylate (KH570) with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and then compositing with poly(vinyl alcohol) (PVA). The coating composed of A151 has a relatively uniform and flat surface structure, due to weaker hydrolysis ability of A151 promoted the smooth condensation speed, compared to KH570. Thanks to the hydrophilic and hydrophobic balance properties of the A151-modulated coating network, the resultant coating exhibits good antifogging performance in the range of 0 °C to 90 °C, which keeps a light transmission of about 85 %. Surprisingly, the coating shows excellent adhesion (350–700 kPa) to the substrate, which is significantly better than other conventional hydrophilic antifogging coatings, and the hydrophilic and hydrophobic modulation capability and the enhanced interfacial adhesion of A151 segments provide the basis of the coating for long-lasting antifogging, which would open up a new way of durable hydrophilic antifogging coatings.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）