Materials
·
2020
·Vol. 13
·期 20
·4551
·
IF 3.057
Linglei Jin,Baikang Zhu,Xuesong Wang,Le Zhang,Debin Song,Jian Guo,Hengcong Tao
With the assistance of surfactant, Fe nanoparticles are supported ong-C3N4nanosheets by a simple one-step calcination strategy. Meanwhile, a layer of amorphous carbon is coated on the surface of Fe nanoparticles during calcination. Transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) were used to characterize the morphology, structure, and composition of the catalysts. By electrochemical evaluate methods, such as linear sweep voltammetry (LSV) and cyclic voltammetry (CV), it can be found that Fe25-N-C-800 (calcinated in 800 °C, Fe loading content is 5.35 wt.%) exhibits excellent oxygen reduction reaction (ORR) activity and selectivity. In 0.1 M KOH (potassium hydroxide solution), compared with the 20 wt.% Pt/C, Fe25-N-C-800 performs larger onset potential (0.925 V versus the reversible hydrogen electrode (RHE)) and half-wave potential (0.864 V vs. RHE) and limits current density (2.90 mA cm−2, at 400 rpm). In 0.1 M HClO4, it also exhibits comparable activity. Furthermore, the Fe25-N-C-800 displays more excellent stability and methanol tolerance than Pt/C. Therefore, due to convenience synthesis strategy and excellent catalytic activity, the Fe25-N-C-800 will adapt to a suitable candidate for non-noble metal ORR catalyst in fuel cells.Keywords:oxygen reduction reaction;iron;coating;P-123
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 31
·25656-25661
·
IF 3.289
Zhixiang Jiang,Katarzyna Matras-Postolek,Ping Yang
Several kinds of hydrophobic quantum dots (QDs) including CdSe, CdTe, CdSe/CdxZn1−xS, and CdTe/CdSe/ZnSe were fabricated via organic synthesis to observe morphology variation during shell coating. CdSe QDs prepared at a relatively high temperature revealed a hexagonal structure and rod morphology. On being coated with a CdxZn1−xS shell, tetrahedron and rod morphologies were observed. It was found that the reaction temperature and injection rate play important roles. The photoluminescence properties of the core/shell QDs depended strongly on their preparation conditions such as temperature and ligands. For CdSe cores created at a relatively low temperature, CdxZn1−xS shell coating resulted in the formation of cubic CdSe/CdxZn1−xS core/shell QDs. This is ascribed to the role of a CdS interlayer. In contrast, multishell CdTe/CdSe/ZnSe QDs revealed a spherical morphology. Furthermore, the self-assembly of QDs with hexagonal structures occurs while regular assembled structures were not observed for QDs with a cubic morphology according to their transmission electron microscopy images. This is ascribed to a dipole force between QDs. This phenomenon is just related to the morphology and crystal structures rather than their composition.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Siwen Wang,Zihang Xu,Tao Xu
The attapulgite (ATP) is one of important raw materials of ceramics and often used as a loading carrier. To control the release rate of composite flame retardant (CFR) when exposed to a fire, and to meet the multi-stage flame retarding requirements, the vacuum negative pressure method was adopted to load four kinds of monomer flame retardants on porous ATP as a carrier after activating pretreatment, respectively. Then CFR nanoparticles with controlled-release effects were prepared by the in-situ polymerization reaction on the surface of monomer flame retardants. After that, zinc hydroxyl stannate , styrene, melamine formaldehyde resin and silicon dioxide with high thermal stability and excellent flame retarding properties were selected as the coating layer of four kinds of monomer flame retardants on ATP carrier. Test results of environmental scanning electron microscope and energy dispersive spectrometer show the satisfactory loading and coating results of CFR nanoparticles. Test results of X-ray photoelectron spectroscopy further confirm the excellent loading conditions and coating film formation on ATP carrier. The thermogravimetry-differential thermal scanning calorimetry tests indicate that the flame retarding duration of both loaded and coated CFR nanoparticles on ATP carrier is prolonged and has a satisfactory controlled-release effect.
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
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Hao Chen,Jingdong Guo,Shandong Tan,Xueqi Zhang,Zhiyuan Sang,De'an Yang
MnO 2 has outstanding potential for application in cathode materials of zinc ion batteries (ZIBs). However, the poor electrical conductivity , poor ion diffusion kinetics, and structural instability greatly limit its rate performance, specific capacity, and cycling stability. Herein, we prepared PEDOT-coated MnO 2 cathode material with oxygen vacancy defects, namely Vö-MnO 2 @PEDOT, by Dual-modification of MnO 2 nanowires. The PEDOT coating optimizes the electron transfer capability of the material while inhibiting the dissolution of MnO 2 . The oxygen vacancies accelerate ion diffusion. Vö-MnO 2 @PEDOT possesses a joint energy storage mechanism, containing the insertion/extraction of H + /Zn 2+ and dissolution/precipitation of MnO 2 . This joint energy storage mechanism explains the high specific capacity and the increase in capacity. The Vö-MnO 2 @PEDOT displays a high specific capacity of 400 mAh/g at 0.2 A/g. Besides, at 2 A/g, Vö-MnO 2 @PEDOT outputs a high capacity of 213 mAh/g after 2000 cycles. This research provides a feasible research idea for the performance optimization of manganese oxide cathode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ChemNanoMat
·
2024
·
IF 2.6
Jiangnan Guo,Shuozhen Hu,Xinsheng Zhang,Shigang Sun
Utilizing carbon coated ferroelectric materials to introduce polarization-induced electric field (PIEF) stimulates research of electric field-assisted catalysts for various reactions. However, effect of PIEF on carbon coating mechanism has not been studied. Herein, tourmaline nanoparticles (TNPs) with spontaneous dipole moments were applied as the PIEF supplier and sucrose was utilized as the carbon precursor to synthesize carbon coated TNPs (TNP@SC) to uncover the influence of PIEF on the carbon coating and catalytic activity of Pd toward formic acid decomposition (FAD). PIEF enhanced the adsorption capacity of TNPs for the caramelized intermediate species and increased H+ concentration by facilitating water ionization. Polymerization of adsorbed caramelized intermediate species on TNPs was accelerated. Uniformly coated carbon layer with more defects, larger specific surface area, and higher porosity was coated on TNP. Such surface properties of the carbon layer were beneficial for strongly anchoring ultrafine Pd nanoparticles. Owing to the specific properties of carbon layer and existence of PIEF, Pd/TNP@SC exhibited higher FAD activity than the catalysts absent of PIEF. Stronger PIEF leaded to higher initial turnover frequency. This study provides guidance to supply electric field for catalysis.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
FirePhysChem
·
2023
·
IF 0
Binghui Duan,Hongchang Mo,Bojun Tan,Minghui Xu,Xianming Lu,Ning Liu,Bozhou Wang
The weak interfacial interaction and high sensitivity is a longstanding problem for nitramine explosives. Herein, polyhydroxyethyl acrylate nitrate (PANE) was adopted to passivate three nitramine explosives through a facile and efficient in situ polymerization method. The core-shell structure of the PANE-coated composites was confirmed after detailed morphological and structural characterization. As a result, we find that, the hydrophobic PANE shell improved the adhesion work between the explosives and fluoropolymer (F 2314 ) binder because of the enriched interfacial interactions. Besides, 2% PANE can retard the crystal transformation of CL-20 and HMX explosives by 10.7 °C and 4.3 °C, but does not affect the thermal decomposition behavior. The mechanical sensitivity of PANE-coated composites decreased more significantly than raw explosives and the mixed samples. As a typical example, the impact and friction sensitivity of CL-20@PANE composite with 2.0% shell content is practically halved when compared to raw CL-20 with the characteristicheight ( H 50 ) of 32.2 cm and the explosionprobability ( P ) of 50%. This study offers a simple, effective and universal method for design and preparation of energetic composites with high safety performance.
研究领域:
材料科学
·
化学工程
·
安全工程
✓ 已验证
DOI
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Mingwei Liang,Weijing Wang,Yi Jiang,Chenyang Liao,Qin Long,Xuefei Lai,Li Liao
The commercial application of silicon is still impeded by poor conductivity and significant volume change. In this work, a C@Si@G composite was synthesized by a facile chemical solution reaction and carbonization procedure with cocoon silk as a natural carbon source. This composite has a sandwich structure, where Si nanoparticles as a sandwich middle layer and graphene (G) as an out layer. And it possesses the advantages of flexible, nitrogen-doped and is environmentally friendly. The optimized C@Si@G-15 composite is used as a self-supporting anode without a current collector, and it shows a reversible discharge capacity of 972 mAh g −1 after 120 cycles at 1 A g −1 and a relatively high capacity of 1070 mAh g −1 after 300 cycles at 200 mA g −1 , demonstrating the effect of coating the N-doped carbonized silk and the graphene synergistically to improve electrical connectivity and to constrain the pulverization of Si nanoparticles. Hence, it delivers great potential for application on wearable devices .
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 3
·454
·
IF 3.164
Qian Wang,Fuping Dong,Jun Dai,Qingpo Zhang,Meng Jiang,Yuzhu Xiong
Fertilizer is very important for increasing food yield, but the extensive use of fertilizer will cause environmental pollution. To enhance the effectiveness of fertilizer, we developed the double organic silicone-modified recycled-oil-based polyurethane as a coating material to prepare degradable polymer coating urea for constant fertilizer release. The moisture, heat resistance, and sustained release properties of polyurethane coating materials were investigated by modification with hydroxyl-terminated polydimethyl silicone (HTPMS) and γ-Aminopropyl triethoxy silane (KH550). The content and distribution of the siloxane groups were effectively controlled by adjusting the content ratio of two kinds of organosilicon. Meanwhile, the organic–inorganic hybrid structure was further controlled to form three-dimensional networks with a uniform distribution and a small scale. The moisture and heat resistance of polyurethane were thus improved, resulting in reduced porosity and an excellent sustained release performance. Observably, the best sustained release property of modified polyurethane coated urea was obtained when the ratio of KH550 to HTPMS is 0.3:0.7.Keywords:recycled oil;polyurethane;coating materials;three-dimensional networks;sustained release
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-5
·
IF 2.481
Wang Yanming,Wang Yajing,Wang Fei
Well-crystallized Li 2 NiTiO 4 nanoparticles are rapidly synthesized by a molten salt method using a mixture of NaCl and KCl salts. X-ray diffraction pattern and scanning electron microscopic image show that Li 2 NiTiO 4 has a cubic rock salt structure with an average particle size of ca. 50 nm. Conductive carbon-coated Li 2 NiTiO 4 is obtained by a facile ball milling method. As a novel 4 V positive cathode material for Li-ion batteries, the Li 2 NiTiO 4 /C delivers high discharge capacities of 115 mAh g -1 at room temperature and 138 mAh g -1 and 50°C, along with a superior cyclability.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
·
2015
·
IF 6.217
Honglai Zhang,Zhaohui Li,Shishun Yu,Qizhen Xiao,Gangtie Lei,Yanhuai Ding
Carbon-encapsulated LiMn 2 O 4 (LMO@C) spheres were prepared using polymer microgel reactor, in which Mn 2+ ions are hydrolyzed in situ to form Mn(OH) 2 , and followed by annealing at a high temperature. The LMO@C spheres are constructed with the spinel LiMn 2 O 4 nanospheres that embedded in a porous carbon matrix uniformly. Owing to possessing three-dimensional (3D) electron-conductive and 3D ion-conductive networks, the LMO@C spheres exhibit high rate capability. They can deliver the specific capacities of 142, 137, 126, 107, and 91 mAh g −1 at the rates of 0.1C, 1C, 5C, 10C, and 20C (1C = 148 mA g −1 ), respectively. Owing to carbon encapsulation, the LMO@C spheres can retain 80% of the initial capacity at 1C rate after 1000 cycles at 25 °C, displaying stable cycling performance. The results suggest that the LMO@C spheres are promising cathode materials for high-power lithium-ion batteries.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 19
·6787
·
IF 4.6
Yuan Zhao,Qianlong Fan,Yinhua Liu,Shuwen Wang,Xudong Guo,Liujia Guo,Mengcheng Zhu,Xuan Wang
In order to separate the colloidal in high-turbidity water, a kind of magnetic composite (Fe3O4/HBPN) was prepared via the functional assembly of Fe3O4and an amino-terminal hyperbranched polymer (HBPN). The physical and chemical characteristics of Fe3O4@HBPN were investigated by different means. The Fourier Transform infrared spectroscopy (FTIR) spectra showed that the characteristic absorption peaks positioned at 1110 cm−1, 1468 cm−1, 1570 cm−1and 1641 cm−1were ascribed to C–N, H–N–C, N–H and C=O bonds, respectively. The shape and size of Fe3O4/HBPN showed a different and uneven distribution; the particles clumped together and were coated with an oil-like film. Energy-dispersive spectroscopy (EDS) displayed that the main elements of Fe3O4/HBPN were C, N, O, and Fe. The superparamagnetic properties and good magnetic response were revealed by vibrating sample magnetometer (VSM) analysis. The characteristic diffraction peaks of Fe3O4/HBPN were observed at 2θ = 30.01 (220), 35.70 (311), 43.01 (400), 56.82 (511), and 62.32 (440), which indicated that the intrinsic phase of magnetite remained. The zeta potential measurement indicated that the surface charge of Fe3O4/HBPN was positive in the pH range 4–10. The mass loss of Fe3O4/HBPN in thermogravimetric analysis (TGA) proved thermal decomposition. The –C–NH2or –C–NH perssad of HBPN were linked and loaded with Fe3O4particles by the N–O bonds. When the Fe3O4/HBPN dosage was 2.5 mg/L, pH = 4–5, the kaolin concentration of 1.0 g/L and the magnetic field of 3800 G were the preferred reaction conditions. In addition, a removal efficiency of at least 86% was reached for the actual water treatment. Fe3O4/HBPN was recycled after the first application and reused five times. The recycling efficiency and removal efficiency both showed no significant difference five times (p> 0.05), and the values were between 84.8% and 86.9%.Keywords:hyperbranched polymer;Fe3O4;coating;magnetic separation;water treatment
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 140
·期 24
·e53955
·
IF 3
Xiaodong Bai,Licheng Deng,Yancheng Yan,Hua Hu,Yumei Luo,Xuetong Cai
Lost circulation will cause huge economic losses every year. In order to effectively reduce the harm of lost circulation to drilling, it is particularly important to use reasonable and efficient lost circulation materials (LCM). As a kind of water-absorbing, expandable and deformable LCM, water-absorbing resin can adapt to holes and cracks of different sizes. In this study, a kind of encapsulated water-absorbing resin LCM (PMMA/PNAD) was proposed. The water-absorbing resin is synthesized by acrylamide (AM), 2-acrylamide-2-methyl-propane sulfonic acid (APMS) and diallyl dimethyl ammonium chloride (DMDAAC) as reaction monomers through aqueous solution polymerization. The shell material is polymethylmethacrylate (PMMA), which is coated on the surface of the water-absorbing resin by oil phase separation method. The results of the experimental evaluation indicate that the water-absorbing resin possesses robust water-absorbing and swelling properties, which significantly affect the rheological properties of the drilling fluid. However, the coated shell can effectively mitigate the impact of the absorbent resin on the drilling fluid. Under the formation environment of 100°C or 2 Mpa, the shell can soften or break to release the absorbent resin. The lost circulation control performance test results show that PMMA/PNAD has good pressure bearing capacity, and can still maintain good lost circulation control at 6.9 Mpa.
研究领域:
材料科学
·
石油工程
✓ 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）