THIN SOLID FILMS
·
2013
·
IF 1.604
Shufang Wang,Shanshan Chen,Guoying Yan,Fuqiang Liu,Shouyu Dai,Jianglong Wang,Wei Yu,Guangsheng Fu
c-axis oriented nanocrystalline Bi 2 Sr 2 Co 2 O y thin films with the average grain size of 25 nm have been achieved by chemical solution deposition combined with a rapid annealing process in oxygen. The resistivity and Seebeck coefficient of the nanostructured films are about 7.0 mΩ·cm and 171 μV/K at 873 K, resulting in a power factor 2–3 times larger than that of the best reported value in the coarse-grained Bi 2 Sr 2 Co 2 O y polycrystalline bulks. Since the thermal conductivity can be greatly reduced due to the increased phonon scattering at the grain boundaries of nanocrystalline films as well as at film surface and at film/substrate interface, great improvements in the ZT are expected in the nanocrystalline Bi 2 Sr 2 Co 2 O y thin films .
研究领域:
材料科学
·
凝聚态物理
·
无机非金属材料
·
能源材料
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2022
·
IF 11.072
Shunan Yin,Jinxian Zhao,Shiping Wu,Xuhui Wang,Yanhong Quan,Jun Ren
Electrochemical reduction of CO 2 to valuable chemicals using electricity from renewable sources is a promising approach to realize the carbon cycle. Here, a novel bimetallic nitrogen-doped carbon catalyst (M-N-C, where M denotes the metal) CoCu–N–C electrocatalyst has been synthesized by pyrolyzing a copper-doped cobalt(II) acetate–phenanthroline complex formed from the metal acetates and 1,10-phenanthroline dissolved in ethanol. The optimal CoCu–N–C catalyst with molar ratio of Cu/(Co + Cu) = 0.15 displayed superior performance, enabling a faradaic efficiency of CO production of 76.5% at an overpotential of 0.57 V as well as an increased CO current density of 8.48 mA cm −2 at −0.98 V versus reversible hydrogen electrode (far superior than the Co–N–C of 4.20 mA cm −2 and Cu–N–C of 0.07 mA cm −2 ) and a decreased charge-transfer resistance compared with Co–N–C and Cu–N–C catalysts. The addition of Cu, which serves as a structure promoter to improve the dispersion of Co, thereby providing sufficient Co-N x active sites for the electrochemical CO 2 reduction reaction (CRR). Moreover, doping Cu changes the electronic environment around Co slightly and promotes the charge transfer capability so that reduces the energy barrier of potential-limiting energy, thereby improving the CRR performance of catalyst.
研究领域:
材料科学
·
电化学
·
可再生能源
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
·
2024
·
IF 3.1
Guanru Chen,Fengjian Chu,Shuheng Zhang,Wangyu Li,Shiwen Zhou,Wei Wei,Weiwei Chen,Xiaozhi Wang,Lei Yue,Hongru Feng,Yanli Cui,Yuanjiang Pan
C–H bond ortho-substitution reaction has always been a significant and challenging topic in organic chemistry. We proposed a synthesis method based on microwave plasma torches. High-resolution mass spectrometry was used to monitor rapid reaction products. 2-Alkylbenzimidazole can be formed through the reaction of phenylnitrenium ion and nitriles on a millisecond scale. This reaction can achieve the one-step formation of benzimidazoles from benzene ring single-substituted compounds without the addition of external oxidants or catalysts. A similar C–H bond activation reaction can be accomplished with ketones. Meanwhile, the microwave plasma reactor was modified, and the resulting 2-methylbenzimidazole was successfully collected, indicating the device has good application potential in organic reactions such as C–H bond activation reaction.
研究领域:
有机化学
·
合成化学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2017
·
IF 5.951
Linglin Zhou,Guilong Zhang,Jie Tian,Dongfang Wang,Dongqing Cai,Zhengyan Wu
Core–shell magnetic Fe3O4@C nanospheres functionalized with active chemical groups were synthesized via a one-step template-free solvothermal process and employed to remove hexavalent chromium (Cr(VI)) in aqueous media. The structure of Fe3O4@C nanoparticles could be effectively adjusted by the concentration of precursor. The Fe3O4 core possessed a high magnetism for the convenient separation of Fe3O4@C from aqueous solution, and high porosity and abundant functional groups (−OH, −COOH, and C═C) of carbon layer contributed to a superior performance on Cr(VI) removal. Therein, Cr(VI) ions could be efficiently adsorbed into the carbon layer and reduced to trivalent chromium (Cr(III)) mainly by C═C, and the resulting Cr(III) were chelated by the −COOH group. Noteworthy, the carbon layer thickness, pore size, and amount of chemical groups significantly increased with the increase of Fe3O4@C particle size resulting in a rising removal efficiency on Cr(VI). This study provides a promising approach for removing Cr(VI) and may have a huge application potential.
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
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yanxu Wang,Lijia Huang,Tian C. Zhang,Yan Wang,Shaojun Yuan
Ammonia gas (NH 3 ) is a notorious malodorous pollutant with detrimental effects on environment and human health. Removing NH 3 through photocatalytic oxidation remains a challenging task due to unclear reaction mechanisms. In this study, DFT simulation results revealed that C doped TiO 2 could extend the photo-response range to the visible region, but the introduction of deep impurity levels was found to accelerate photogenerated carrier recombination. Fortunately, the rational doping of Mo was found to mitigate this negative effect. Accordingly, Mo, C co-doped TiO 2 was synthesized via a facile low-temperature calcination process, resulting in unique band structure that enhanced the photocatalytic oxidation of NH 3 . Notably, in-situ DRIFTS and DFT results demonstrated that the gradual reaction of NH 3 adsorbed on Mo atoms with oxygen species through the N 2 H 4 mechanism, promoting the formation of N 2 . These findings offer insights into the design of efficient photocatalysts for NH 3 removal under visible light, and present a promising technology for indoor air pollution control.
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
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Xing Xu,Yunlong Xu,Huang Zhang,Mandi Ji,Hui Dong
The NiO doped LiFePO 4 /C composite was synthesized by a simple solid state method. The structure and morphology of synthesized particles were characterized by XRD, Raman spectrum , SEM, TEM and EDS. Electrochemical performance of the pristine and nickel oxide modified samples was evaluated by galvanostatic charge-discharge test, CV , and EIS . The results indicate that NiO doped LiFePO 4 /Li type coin cell exhibits improved specific capacity and cycle stability, especially at high rates. Among all the modified samples, the 5.0%wt NiO doped sample shows the best electrochemical performance, which achieves a specific capacity of 129 mA h g −1 at 1 C current rate due to the modest graphitization of carbon layer on the surface of LiFePO 4 particles. The results indicate that nickel oxide modification is an effective way to improve the electrochemical performance of LiFePO 4 /C cathode materials for lithium ion batteries .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Industrial Chemistry & Materials
·
2023
·
IF 0
Yu Chen,Chang-Long Tan,Jing-Yu Li,Ming-Yu Qi,Zi-Rong Tang,Yi-Jun Xu
Photocatalytic hydrogen (H2) production coupled with selective oxidation of organic compounds into high-value-added organic intermediates has expansive prospects in the utilization and transformation of solar energy, which meets the development requirements of green chemistry. In this work, high-efficiency hole cocatalyst PdS-decorated In2S3 flower-like microspheres are fabricated for the effective visible-light-driven C–N coupling of amines to imines coupled with H2 evolution. Owing to the establishment of the internal electric field, which further boosts the transfer of photoexcited holes to PdS, PdS–In2S3 exhibits distinctly enhanced photocatalytic redox performance, which is 39.8 times higher for H2 and 14.3 times higher for N-benzylidenebenzylamine than that of the blank In2S3, along with high selectivity and stability. Furthermore, the practicability of dehydrogenation coupling of various aromatic amines to the corresponding C–N coupling products on PdS–In2S3 has been demonstrated and a plausible reaction mechanism has been proposed. This work is anticipated to stimulate further interest in establishing an innovative photoredox platform for selective organic synthesis coupled with H2 evolution in a green and sustainable way.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 已验证
DOI
Journal of Energy Chemistry
·
2019
·
IF 5.162
Meng Zhang,Xuezhang Xiao,Bosang Luo,Meijia Liu,Man Chen,Lixin Chen
Magnesium hydride has been seen as a potential material for solid state hydrogen storage , but the kinetics and thermodynamics obstacles have hindered its development and application. Three-dimensional flower-like TiO 2 @C and TiO 2 were synthesized as the catalyst for MgH 2 system and great catalytic activities are acquired in the hydrogen sorption properties. Experiments also show that the flower-like TiO 2 @C is superior to flower-like TiO 2 in improving the hydrogen storage properties of MgH 2 . The hydrogen desorption onset and peak temperatures of flower-like TiO 2 doped MgH 2 is reduced to 199.2 °C and 245.4 °C, while the primitive MgH 2 starts to release hydrogen at 294.6 °C and the rapid dehydrogenation temperature is even as high as 362.6 °C. The onset and peak temperatures of flower-like TiO 2 @C doped MgH 2 are further reduced to 180.3 °C and 233.0 °C. The flower-like TiO 2 @C doped MgH 2 composite can release 6.0 wt% hydrogen at 250 °C within 7 min, and 4.86 wt% hydrogen at 225 °C within 60 min, while flower-like TiO 2 doped MgH 2 can release 6.0 wt% hydrogen at 250 °C within 8 min, and 3.89 wt% hydrogen at 225 °C within 60 min. Hydrogen absorption kinetics is also improved dramatically. Moreover, compared with primitive MgH 2 and the flower-like TiO 2 doped MgH 2 , the activation energy of flower-like TiO 2 @C doped MgH 2 is significantly decreased to 67.10 kJ/mol. All the improvement of hydrogen sorption properties can be ascribed to the flower-like structure and the two-phase coexistence of TiO 2 and amorphous carbon . Such phase composition and unique structure are proved to be the critical factor to improve the hydrogen sorption properties of MgH 2 , which can be considered as the new prospect for improving the kinetics of light-metal hydrogen storage materials.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 55
·43972-43977
·
IF 3.84
Jun Hu,Dekui Shen,Shiliang Wu,Huiyan Zhang,Rui Xiao
The microwave-assisted cleavage of C–O linkages in benzyl phenyl ether was investigated at 200 °C in the presence of ZrP or SBA-15 doped with or without metal catalyst (Pd/C or Ru/C). The total yield of phenol and benzyl alcohol from benzyl phenyl ether depolymerization with ZrP was 26.91%, while the yield of phenol reached 26.11% for that with Pd/C. Hybrid catalysts performed effectively for promoting the formation of phenol. A conversion of 85.70% was achieved with ZrP–Pd/C catalyst, and the selectivity to phenol reached 47.32%. The highest yield of phenol was obtained at 1 h, and repolymerization was remarkable at longer reaction time. Based on the reaction using phenol and benzyl alcohol as the reactants, benzyl phenyl ether might be decomposed into phenol and benzyl alcohol following with the repolymerization producing thermally stable polymers in the presence of Pd.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
DRYING TECHNOLOGY
·
2020
·
IF 2.988
Wei Wang,Shuo Zhang,Yanqiu Pan,Yujia Tang,Guohua Chen
To explore the effect of wave-absorbing material aided microwave heating on freeze-drying of initially porous frozen material, a lab-scale microwave freeze-dryer was designed with solid-state source selected as the microwave source instead of the traditionally used magnetron. Vitamin C was employed as the solute in aqueous solution. “Soft-ice” freezing technique was adopted to prepare solid and porous frozen materials. Experimental results showed that the solid sample by soft-ice freezing can successfully avoid structural collapse during freeze-drying, and the porous frozen material can significantly intensify mass transfer of the freeze-drying process. Under the operating conditions of 35 °C and 20 Pa, the drying time of the porous sample with the initial saturation of 0.25 decreased by 30.4% compared with the solid one, and the residual moisture content of dried product decreased with the initial saturation reducing. SEM images of the dried products revealed that the porous material had a loose pore structure and a tenuous solid skeleton, which is favorable to the migration of sublimated/desorbed vapor and the desorption of bound moisture. Evidences also showed that appropriately increasing radiation temperature led to reducing the drying time, while changing chamber pressure had an insignificant effect on freeze-drying. With sintered silicon carbide (SiC), which is a kind of wave-absorbing material, as the supporting pad of sample, microwave heating can greatly improve heat transfer of the freeze-drying process. Under the same operating conditions, the drying time of the porous sample with the microwave input power of 5 W was 28.1% shorter than that of the same sample without microwave heating, and 50.0% shorter than that of the solid sample for conventional freeze-drying. Wave-absorbing material aided microwave freeze-drying of the porous material frozen with preformed pores is a feasible and effective way to achieve the simultaneous intensification of heat and mass transfer in freeze-drying.
研究领域:
食品科学与工程
·
化学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Wanhong Yu,Guifang Li,Changwan Sun,Jianquan Zhang,Li Yang,Yichun Zhou
In this paper, we propose an effective method for doping WC into Ta-Hf-C ceramics to significantly enhance their densification and mechanical properties. An increasing WC doping amount from 0 to 20 at.%, enhances the densification of Ta-Hf-C ceramics from 92.4 % to 99.1 %. This is mainly due to the fact that the doping of WC effectively removes the harmful oxygen impurities from the ceramics, thereby increasing their sintering activity. Furthermore, the doping of WC plays an active role in the mechanical properties of the ceramics. The Ta-Hf-C doped with 15 at.% WC has the highest value of 36.41 GPa for nano-hardness due to the solid solution strengthening mechanism, while the highest Vickers hardness (38.75 GPa) and fracture toughness (3.76 MPa m 1/2 ) appear in Ta-Hf-C doped with 20 at.% WC. The main toughness mechanism is W segregation at the grain boundary, enhancing grain boundary strength .
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Xinghao Qu,Boyu Li,Yilong Wang,Xiyang Li,Yuping Duan,Xuefeng Zhang,Guimei Shi,Yuanliang Zhou,Xinglong Dong
Electromagnetic pollution is escalating in the advent of the 5 G and forthcoming 6 G era. Ti 3 C 2 T X MXene, an emergent two-dimensional material, has been extensively applied in the field of electromagnetic absorption and shielding owing to its high electrical conductivity, adjustable interlayer spacing, and substantial surface area. However, its practical application as an absorber is severely limited by challenges including face-to-face restacking, surface modification difficulties, and poor impedance matching. Here, carbon-coated NiFe alloy nanoparticles (NiFe@C NPs), fabricated using the DC arc-discharge technique, are electrostatically self-assembled with MXene. This process effectively reduces self-stacking and enhances impedance matching properties. The robust magnetic coupling within NiFe alloy compensates for the deficiency in the magnetic loss capacity of carbon and MXene, while defects in the carbon layer and terminal groups on MXene's surface facilitate dipolar polarization. Furthermore, the heterogeneous interfaces between NiFe@C NPs and MXene produce localized dielectric polarization fields that are conducive to enhancing interfacial polarization. Additionally, the multilayered structure of MXene promotes multiple reflections and scattering of incident electromagnetic waves. When the NiFe@C/MXene composite has a thickness of 2.3 mm, it reaches a minimum reflection loss of −38.40 dB. Computer Simulation Technology (CST) results confirm the high radar cross section reduction value (17.21 dB·m 2 ), indicating the potential of multi-component NiFe/carbon/MXene composite 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
危险品化学品经营许可证（带存储）