JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 53
·期 1
·456-465
·
IF 2.599
Boakye Felix Ofori,Fan Meiling,Cai Haopeng,Zhang Haining
Nitrogen-doped porous carbons with uniformed pore structure and large surface area are promising materials as sorbents for acidic gases and electrocatalysts for oxygen-related reactions. Herein, we report the synthesis of nitrogen-doped porous carbon (NPC) materials through carbonization of imidazole-functionalized polyhedral oligomeric silsesquioxane (POSS) at 900 °C followed by removal of POSS blocks. The imidazole moieties act as both nitrogen and carbon sources and the POSS blocks are nano-sized hard templates. The resulting NPC has a surface area of 980 m 2 g −1 with average pore size of 4.7 nm and the pyridinic nitrogen in the formed NPC contribute to about 33% of overall nitrogen species. The carbon dioxide adsorption property and the electrocatalytic performance toward oxygen reduction reaction of the formed NPC are further evaluated. The formed NPC materials exhibit a total carbon dioxide adsorption capacity of 0.30 mmolg −1 at 30 °C under the partial pressure of carbon dioxide of 0.2 bar. Although the formed NPC is less active than commercial Pt/C catalyst for oxygen reduction reaction, the half-wave potential shifts to the negative side by only about 10 mV after 10000 cycling tests, demonstrating the great stability of the formed NPC materials.
研究领域:
材料科学
·
环境科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2022
·
IF 8.047
Zhidong Yang,Ya Zhang,Hongxia Zhang,Jianghong Zhao,Hu Shi,Ming Zhang,Hengquan Yang,Zhanfeng Zheng,Pengju Yang
Photocatalytic CO 2 reduction into valuable chemicals and fuels is thought to be an effective way to reduce greenhouse gas emissions and achieve sustainable carbon cycling. Recent studies have confirmed that polymeric carbon nitride (PCN) can drive CO 2 reduction reaction under visible light irradiation. However, the pristine PCN typically suffers from moderate efficiency. Herein, nitrogen-vacancies-functionalized PCN (NV S -PCN) photocatalysts are successfully prepared via a novel formic acid-assisted etching protocol for the first time. It is found that the NVs are mainly stemmed from the selectively breaking of surface N-(C) 3 sites within PCN matrix. Steady-state photoluminescence (PL), time-resolved PL, and photocurrent results approve that the NVs can significantly suppress the recombination of photogenerated charge carriers. CO 2 temperature programmed desorption and DFT calculations determine that the NVs modification can optimize the electronic properties of NVs-PCN photosystem, and thus considerably improve the activation of CO 2 , while lower the formation barrier of COOH* intermediates. Consequently, the NVs-PCN photosystem exhibits a 279-fold improvement in CO 2 reduction activity over the pristine PCN under 400 nm light irradiation. Moreover, we successfully prepare another NVs-modified PCN-T (trithiocyanuric acid as a precursor) under the same preparation conditions. This NVs-PCN-T photosystem also shows exceptional performances for photocatalytic CO 2 reduction and hydrogen production with visible light. The apparent quantum yields (AQYs) for CO 2 reduction and hydrogen production reach as high as 6.17 % and 31.08 % at 400 nm, respectively. The insights provided in this work are expected to provide a novel clue for manipulating catalytic properties and advancing the in-depth understanding on the role of defect structure of photocatalysts during CO 2 reduction.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Kunqiao Li,Yanqiu Jiang,Yudong Li,Zhe Wang,Xing Liu,Ping Wang,Debin Xia,Ruiqing Fan,Kaifeng Lin,Yulin Yang
Cyano groups have been successfully introduced on the backbone edge of g-C 3 N 4 to fabricate nitrogen defects under mild conditions, which are derived from incomplete polymerization of g-C 3 N 4 after BaCO 3 utilization. Characterization results indicate that the interfacial interaction between BaCO 3 and carbon nitride is playing a significant role for introducing cyano groups into g-C 3 N 4 . Cyano groups working as electron capture centers are proved to change the band gap of carbon nitride , reducing the recombination rate of electron-hole pairs and promoting charge separation. As expected, the hydrogen evolution rate of nitrogen-defect-modified carbon nitride is improved to 71.57 μmol h −1 , which is 13.5 times that of pristine C 3 N 4 . Meanwhile, the degradation efficiency of methyl orange is promoted (5 times that of pristine C 3 N 4 ). This work is the first report on the fabrication of cyano-group-modified carbon nitride with BaCO 3 utilization, and opens a new door for further exploring environmental-friendly carbon nitrides on energy conversion.
研究领域:
材料科学
·
环境科学
·
能源化学
✓ 已验证
DOI
高影响因子
NANOTECHNOLOGY
·
2023
·Vol. 34
·期 45
·455701
·
IF 3.5
Shuang Wang,Li Yang,Xiaoting Ren,Wenchao Tong,Wei Li,Haojie Li,Junda Huo
Copper azide (CA) has gradually become the chosen priming agent for microexplosive devices as a lead-free green priming agent. However, charge loading is challenging due to its high electrostatic sensitivity, severely limiting its practical application. In this study, copper hydroxide particles were evenly coated on the surface of carbon fiber using electrospinning and quick hot-pressing, and CA-based composites with uniform load were created using the in situ azide technique while keeping good film characteristics. The produced CA-HP film has an electroostatic sensitivity of 3.8 mJ, which is much higher than the raw material of 0.05 mJ. The flame sensitivity has also been increased from 45 to 51 cm, and the use safety has been considerably enhanced. Furthermore, hot-pressed CA-HP films can improve the film's qualities, such as easy cutting and processing into the required shape, compatibility with MEMS processes, and the ability to successfully detonate secondary explosives with only 1 mg. This novel coupling technology expands the possibilities for developing high-safety primers for micro-initiator.
研究领域:
材料科学
·
爆炸物工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Zhonghui Sun,Huiling Liu,Meng Shu,Ziyu Lin,Bing Liu,Yunliang Li,Jiabin Li,Tiechen Yu,Hongyan Yao,Shiyang Zhu,Shaowei Guan
A novel hexaazatrinaphthylene-based (HATN) azo polymer (PAH) was synthesized from a newly designed tri-nitro compound trinitrodiquinoxalino[2,3-a:2′,3′-c]phenazine (HATNTN) through a Zn-induced reductive homocoupling reaction and used as a cathode material for lithium-ion batteries (LIBs). The integration of redox-active HATN units and azo linkages can improve the specific capacity, rate performance, and cycling stability of the PAH cathode. The control LIBs were assembled from HATNTN, in which HATNTN can be electrochemically reduced to an HATN-based azo polymer. Compared with the HATNTN cathode, the PAH cathode delivers higher specific capacities with much-improved cycling stability (97 mA h g–1 capacity retention after 1500 cycles at 500 mA g–1, which is around 28 times that of the HATNTN cathode) and considerably better rate performance (118 mA h g–1 at 2000 mA g–1, which is around 90 times that of the HATNTN cathode), simultaneously. This work provides a chemical polymerization strategy to construct extended π-conjugated azo polymers with multiple redox centers from nitro compounds for developing high-performance LIBs.
研究领域:
有机化学
·
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 19
·期 5
·2817-2825
·
IF 2.328
Xiangning Yang,Jianqiang Bi,Guandong Liang,Yonghan Li,Linjie Meng,Chengge Wu,Xiangyu Zhang
The boron nitride nanosheets (BNNSs)/aluminum nitride (AlN) composites were prepared by hot press sintering at 1600°C. The microstructure, mechanical properties, and thermal conductivity of the samples were measured, and the effect of adding BNNSs to AlN ceramics on the properties was studied. It is found that the addition of BNNSs can effectively improve the mechanical properties of AlN. When the additional amount is 1 wt%, the bending strength of the sample reaches the maximum value of 456.6 MPa, which is 23.1% higher than that of the AlN sample without BNNSs. The fracture toughness of the sample is 4.47 MPa m 1/2 , a 68.7% improvement over the sample without BNNSs. The composites obtained in the experiment have brilliant mechanical properties.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2023
·
IF 11.4
Xiaofei Li,Dengzhou Gao,Ye Li,Yanling Zheng,Hongpo Dong,Xia Liang,Min Liu,Lijun Hou
Estuarine and coastal environments are assumed to contribute to nitrous oxide (N2O) emissions under increasing nitrogen loading. However, isotopic and molecular mechanisms underlying N2O production pathways under elevated nitrogen concentration remain poorly understood. Here we used microbial inhibition, isotope mass balance, and molecular approaches to investigate N2O production mechanisms in estuarine and coastal sediments through a series of anoxic incubations. Site preference of the N2O molecule increased due to increasing nitrate concentration, suggesting the changes in N2O production pathways. Enhanced N2O production under high nitrate concentration was not mediated by bacterial denitrification, but instead was mainly regulated by fungal denitrification. Elevated nitrate concentration increased the contribution of fungal denitrification to N2O production by 11–25%, whereas it decreased bacterial N2O production by 16–33%. Chemodenitrification was also enhanced by high nitrate concentration, contributing to 13–28% of N2O production. Elevated nitrate concentration significantly mediated nirK-type denitrifiers structure and abundance, which are the keystone taxa driving N2O production. Collectively, these results suggest that increasing nitrate concentration can shift N2O production pathways from bacterial to fungal and chemodenitrification, which are mainly responsible for the enhanced N2O production and have widespread implications for N2O projections under ongoing nitrogen pollution in estuarine and coastal ecosystems.
研究领域:
环境科学
·
微生物学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Chemistry B
·
2017
·Vol. 5
·期 46
·9197-9203
·
IF 4.543
Leijing Liu,Fengli Zhang,Bin Xu,Wenjing Tian
Nitric oxide (NO), known as a reactive nitrogen species (RNS), has been considered to be a significant factor in many cell-related biological processes. There is a great desire to develop fluorescent probes that can highly sensitively and selectively detect NO in living cells. Herein, a fluorescent probe, a tetraphenylethene (TPE) derivative TPE-2NH2, with aggregation induced emission (AIE) properties was designed and synthesized. Then silica nanoparticles based on TPE-2NH2 were fabricated for ratiometric detection of NO in vitro with high sensitivity and selectivity. In the presence of NO, the fluorescence of the silica nanoparticles changes from 519 nm (green) to 655 nm (red) because of the chemical reaction between NO and o-phenylenediamine in TPE-2NH2. The silica nanoparticles exhibited very high sensitivity and selectivity towards NO in aqueous buffer, and the response time was as short as 5 minutes. Moreover, the silica nanoparticles can also highly sensitively and selectively respond to NO produced in living cells. When MCF-7 cancer cells were activated by lipopolysaccharides (LPS), which can effectively induce the production of NO, the red emission signal of the silica nanoparticles obviously increased. This demonstrated that the silica nanoparticles showed fine imaging contrast towards NO in MCF-7 cancer cells, which provides a facile tool to detect intracellular NO.
研究领域:
生物化学
·
分析化学
·
细胞生物学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF RAMAN SPECTROSCOPY
·
2017
·Vol. 48
·期 4
·578-585
·
IF 2.969
Hengyong Wei,Mingming Wu,Zhanliang Dong,Ying Chen,Jinglong Bu,Jian Lin,Yun Yu,Yingna Wei,Yi Cui,Ruisheng Wang
The titanium nitride thin film was successfully prepared via direct nitridation of the sol–gel derived TiO 2 thin film at different temperatures in ammonia gas. The composition, microstructure and optical properties of the thin films were characterized in order to investigate their effect on the surface-enhanced Raman scattering (SERS) performance of the thin films. With the nitridation temperatures increasing, the anatase phase transformed into titanium nitride phase in the films and the concentration of nitrogen incorporation increased accordingly. Consequentially, the sol–gel derived TiO 2 thin film was converted to non-stoichiometry titanium nitride (TiO x N y ) thin film, as determined by X-ray diffraction (XRD), RAMAN and X-ray photoelectron spectroscopy (XPS). As a result, a blue-shift of the surface plasmon resonance absorption peaks and narrowing optical band gap of the thin films were observed, leading to the improvement of SERS performance via electromagnetic enhancement mechanism and charge-transfer effect. In addition, the surface of thin films became gradually rough with the nitridation temperatures increasing, ascribed to the growth of titanium nitride crystal grains. Most of all, the thin films nitrided at 1000 °C had the most rough surface, and many ‘hot spots’ formed on the thin film surface accordingly, which were favorable for enhancing SERS-active, and thereby the thin films exhibited the largest SERS enhancement. Copyright © 2017 John Wiley & Sons, Ltd.
研究领域:
材料科学
·
光谱学
✓ 已验证
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2017
·
IF 4.075
Haoming Fang,Shu-Lin Bai,Ching Ping Wong
A series of novel flexible polymer composites consisted of boron nitride foam (BNF), boron nitride nanosheets (BNNS) and polydimethylsiloxane (PDMS) were designed and fabricated by vacuum-assisted infiltrating BNNS/PDMS mixtures into 3D BNF synthesized via chemical vapor deposition (CVD). Their microstructure, thermal, mechanical and dielectric properties were studied. Contributed to the interconnected networks of BNF and synergistic effect of BNNS with BNF, 10 wt% BNNS/BNF/PDMS composite shows a high thermal conductivity of 0.56 W m −1 K −1 , high heat resistance index of 275.6 °C, 33% increment of Young’s modulus compared to PDMS, relative permittivity of 3, dissipation factor of 0.0051, EMI shielding effectiveness of 1.5 dB at X band and breakdown strength of 21.8 MV/m. Due to the outstanding comprehensive properties, BNNS/BNF/PDMS composites have a promising potential application in wide electronic packaging field.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2022
·Vol. 169
·期 6
·062501
·
IF 4.386
Chanez Maouche,Yazhou Zhou,Bing Li,Chao Cheng,Zirui Wu,Xue Han,Shaosheng Rao,Yi Li,Nasir Rahman,Juan Yang
Iron-nitrogen-carbon graphitic (Fe-N-C), a noble metal-free catalyst holds a lot of promise to substitute platinum (Pt) as an efficient catalyst in the oxygen reduction reaction (ORR). However, the synthesis process and the stabilization of single atoms that tend to aggregate, without jeopardizing the catalytic activity remain challenging. Here we demonstrate a stabilized assisted method for the preparation of Fe-N-C electrocatalyst by using graphitic carbon nitride (g-C3N4) nanosheet as a template. Fe ions are absorbed on the surface of g-C3N4 and imprisoned after the addition of pyrrole, preventing Fe migration that may result in nanoparticles. During the pyrolysis, Fe atoms coordinated with N provided by g-C3N4 and pyrrole on graphitic carbon to form Fe-N-C with a metal loading of 5.4 wt%. Moreover, FeNx species were introduced in the graphitic carbon, where the coexistence of micro and mesopores were favorable to offer a larger density of active sites compared to Fe/NP without pyrrole. Fe-N-C demonstrated a good electrocatalytic performance with a half-wave potential (E1/2) of 0.82 V (vs reversible hydrogen electrode (RHE)) higher than Fe/NP (0.76 V) and close to Pt/C, with a superior long stability of 85% in alkaline media after 40000 s.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 13
·5571-5586
·
IF 3.553
Yan Yinqiang,Jamal Ruxangul,Yu Zongna,Zhang Ruanye,Zhang Wenli,Ge Yi,Liu Yingcheng,Abdiryim Tursun
A novel electrochemical sensor with thiol-grafted PEDOT/ N -doped graphene ( N -Gr/PEDOT-MeSH) and thiol-grafted PEDOT/graphitic carbon nitride (g-C 3 N 4 /PEDOT-MeSH) composites was fabricated for the detection of paracetamol (PAR). The formation mechanism of the obtained structure was thoroughly studied. And from the electrochemical results, the synergistic effect between the PEDOT-MeSH and g-C 3 N 4 or N -Gr improved the electron transfer and conductivity of the modified electrodes and enhanced the sensing responses toward the electrochemical oxidation of PAR. The calibration curve of N -Gr/PEDOT-MeSH and g-C 3 N 4 /PEDOT-MeSH composites exhibited the wider linear responses for PAR, ranging from 2 to 1680 µM and 0.4 to 1280 µM, and the detection limits ( S / N = 3) were 1.42 µM and 1.0 µM, respectively. Furthermore, the obtained composites exhibited the excellent reproducibility, lower detection limit and good stability. And it was capable of detecting PAR in real samples with a satisfying result.
研究领域:
材料科学
·
分析化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）