ChemElectroChem
·
2017
·Vol. 5
·期 3
·471-477
·
IF 4.136
Jingchun Jia,Huijuan Yang,Genxiang Wang,Peng Huang,Pingwei Cai,Zhenhai Wen
Graphical All-round activity : Hybrids of Fe/Fe 3 C embedded in N-doped carbon nanotubes (Fe/Fe 3 C@NCNTs) are prepared by pyrolyzing mixtures of Fe 3 O 4 nanoparticles and dicyandiamide. Fe/Fe 3 C@NCNTs show a highly multifunctional catalytic activity for the oxygen evolution, oxygen reduction, and CO 2 reduction reactions. Hybrids of Fe/Fe 3 C embedded in N-doped carbon nanotubes (Fe/Fe 3 C@NCNTs) are prepared by pyrolyzing mixtures of Fe 3 O 4 nanoparticles and dicyandiamide. The systematic electrochemical study of Fe/Fe 3 C@NCNTs shows a decent catalytic activity toward the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). The sample of Fe/Fe 3 C@NCNTs at 750 °C exhibits a remarkably high activity with an onset potential of 1.47 V for the OER, and an onset potential of 0.96 V and half-wave potential 0.88 V for the ORR, which inspired us to set up a rechargeable Zn-air battery with such Fe/Fe 3 C@NCNT nanohybrids as the cathode materials, showing a maximum power density of 198 mW cm −2 and long-term stability after 500 cycles. We also demonstrate that Fe/Fe 3 C@NCNTs present favorable electrocatalytic activity towards the CO 2 reduction reaction (CO 2 RR) with a low onset potential and good selectivity. The major products are a mixture of H 2 and CO gases that can be used for methanol production in the Fischer−Tropsch process.
研究领域:
材料科学
·
电化学
·
能源科学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2022
·
IF 4.177
Weifeng Su,Ning Yan,Fan Liu,Zigeng Liu,Guangqi Zhu,Songrui Wang,Xingjiang Liu,Wei Wang
The attenuation process of the oxygen reduction reaction (ORR) catalytic performance for Fe SAC@G catalysts under different discharging conditions, including KOH concentrations, solution temperatures, and discharging potentials, was investigated by electrochemical measurements. The ORR catalytic activity attenuation resulting from the change in KOH concentration and temperature becomes apparent in a negative discharging potential range and elevated discharging temperature. In addition, the more negative discharging potential significantly causes the ORR catalytic activity attenuation. Scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy analyses indicate that, with the prolongation of the discharge time, the nanocolumns of the as-prepared catalyst gradually dissolve, while a flowerlike discharge byproduct composed of elements C and N keeps growing on the surface of the catalyst. The weakest Fe–N bonds first break, resulting in the attenuation of the ORR catalytical performance. Then, the weak C–Cunit bonds connecting the structural units of the catalysts break, leading to the gradual collapse in the structure of the catalysts. The Fe–N4 coordination structure gradually transforms into Fe–N3, Fe–N2, and Fe–N coordination structures. Based on the analyses combined with the density functional theory (DFT) calculations of bond strength, a discharge attenuation mechanism of the structural collapse of the catalyst for the formation of the discharge byproduct with ring structure is proposed.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Zhengwen Fan,Xinjiao Cui,Jiankun Wei,Chan Chen,Haolin Tang,Junsheng Li
Fe N C is the most promising material to replace the noble metal catalyst for cathodic oxygen reduction reaction in proton exchange membrane fuel cells (PEMFCs). However, the practical performance of Fe N C catalyst is significantly limited by its low active site (Fe-N 4 ) density. Herein, we propose to promote the formation of Fe-N 4 active sites in Fe N C catalyst by strengthening the interaction of N precursors and Fe precursors during the carbonization synthesis. In our approach, ionic liquid (IL, [EMIM][NTf 2 ]) with high nitrogen content and good thermal stability is caged in the pores of Fe-ZIF-8 through the host–guest interactions. These interactions are critical for the preservation of Fe and N species and formation of active sites during the synthesis. The optimal catalyst developed with this approach (Fe 0.05 N C/10) has a high density of accessible Fe-N 4 sites (1.88*10 19 sites g −1 ). Therefore, in both acidic and alkaline media, Fe 0.05 N C/10 showed excellent ORR activity comparable to commercial Pt/C catalyst. Moreover, PEMFC performance with a peak power density of 300 mW cm −2 was demonstrated with Fe 0.05 N C/10 under H 2 /O 2 conditions. The synthetic approach reported herein may be used for tailoring of advanced catalyst with high intrinsic activity.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 5
·3455-3474
·
IF 1.674
Sun Xiao,Guo Rui-tang,Li Ming-yuan,Sun Peng,Pan Wei-guo,Liu Shu-ming,Liu Jian,Liu Shuai-wei
Fe was used as the modifier to improve the performance of CeZr 2 O
x
catalyst for the selective catalytic reduction (SCR) reaction with ammonia. Experimental results revealed that proper Fe species (Fe/Ce molar ratio = 2) could effectively improve the SCR activity of CeZr 2 O
x
, along with the elevated resistance to SO 2 and H 2 O. The characterization results including BET, XRD, H 2 -TPR and NH 3 -TPD confirmed that Fe species in Fe 2 CeZr 2 O
x
catalyst could inhibit the formation of ZrO 2 crystals and lead to higher reducibility and surface acidity. In addition, more Ce 3+ and surface active oxygen species could be detected on Fe 2 CeZr 2 O
x
compared with CeZr 2 O
x
. By means of in situ DRIFT technique, it could be deduced that the SCR reaction process over Fe 2 CeZr 2 O
x
was accelerated mainly through theL–H pathway due to the advanced adsorption of NH 3 and NO
x
species, along with the promoted NO conversion to NO 2 . Therefore, the modification of CeZrO
x
catalyst by Fe had a significant stimulation effect on its low-temperature SCR performance.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2022
·Vol. 38
·期 5
·1232-1238
·
IF 2.726
Chen Weijie,Xia Huicong,Guo Kai,Jin Wangzhe,Du Yu,Yan Wenfu,Qu Gan,Zhang Jianan
Lithium-sulfur(Li-S) batteries have been puzzled by the “shuttle effect”. In the recent years, catalytic materials present a huge potential for solving this problem. However, the exploitation for catalytic activity was still challenging in Li-S batteries. In this article, we put forward a single atom catalyst (SAC) of FeN 4 coupled with Fe 3 C on the N-doped carbon (FeN 4 /Fe 3 C@NC) by one-step pyrolysis method. The FeN 4 and Fe 3 C synergistically catalyze the polysulfides conversion when the N-doped carbon provides the high conductive three-dimensional skeleton in Li-S batteries. As a result, the FeN 4 /Fe 3 C@NC shows a specific capacity of 1100 mA·h/g at 0.2 C(1 C=1675 mA/g). In addition, the FeN 4 /Fe 3 C@NC maintains 99.01% of the pristine specific capacity after 100 cycles at 0.5 C, indicating the improved electrochemical performance in Li-S batteries. This work sheds new lights on the design of engineering catalysts for developing high-performance Li-S batteries.
研究领域:
电化学
·
能源材料
·
纳米催化
·
电池技术
·
材料化学
✓ 已验证
DOI
高影响因子
INDOOR AND BUILT ENVIRONMENT
·
2025
·
IF 2.9
Pengfei Zhang,Wenjian Han,Bo Zhou,Haiqian Zhao
The metal-organic framework MIL-100(Fe) is a novel humidity-regulating material, but it has poor water vapour desorption performance. To address this issue, MIL-100(Fe) was modified using 20% lithium chloride (LiCl), forming stable coordination bonds through ion-dipole interactions. These bonds attract water molecules, enhancing the adsorption capacity and improving the structural stability of the material. After modification, its moisture capacity was increased by 2.42 times, and the desorption amount was increased by 7.22 times, with an overall improvement in moisture adsorption–desorption equilibrium. However, the use of inorganic salts presents a leakage problem in high-humidity environments. To counter this, a 3% ethyl cellulose (EC) coating was applied to the modified MIL-100(Fe). Through surface interactions, this modification improved the material's adsorption performance in non-polar environments, preventing deliquescence in long-term high-humidity conditions. The hydrophobic angle of the modified composite material reached 93°, making the surface hydrophobic. The moisture capacity of the composite material was 1.83 times that of the pure MOF, and the desorption amount was increased by 5.2 times, significantly enhancing the material's environmental humidity regulation performance. Additionally, the material demonstrated good reusability, extending its lifespan, making it suitable for use as an intelligent humidity control material in construction.
研究领域:
材料科学
·
环境功能材料
·
纳米多孔材料
·
建筑节能
·
智能响应材料
✓ 已验证
DOI
高影响因子
Nature Communications
·
2023
·Vol. 14
·期 1
·1-9
·
IF 16.6
Zang Ying,Lu Di-Qiu,Wang Kun,Li Bo,Peng Peng,Lan Ya-Qian,Zang Shuang-Quan
Catalysts capable of electrochemical overall water splitting in acidic, neutral, and alkaline solution are important materials. This work develops bifunctional catalysts with single atom active sites through a pyrolysis-free route. Starting with a conjugated framework containing Fe sites, the addition of Ni atoms is used to weaken the adsorption of electrochemically generated intermediates, thus leading to more optimized energy level sand enhanced catalytic performance. The pyrolysis-free synthesis also ensured the formation of well-defined active sites within the framework structure, providing ideal platforms to understand the catalytic processes. The as-prepared catalyst exhibits efficient catalytic capability for electrochemical water splitting in both acidic and alkaline electrolytes. At a current density of 10 mA cm −2 , the overpotential for hydrogen evolution and oxygen evolution is 23/201 mV and 42/194 mV in 0.5 M H 2 SO 4 and 1 M KOH, respectively. Our work not only develops a route towards efficient catalysts applicable across a wide range of pH values, it also provides a successful showcase of a model catalyst for in-depth mechanistic insight into electrochemical water splitting.
研究领域:
电化学
·
催化
·
材料科学
·
能量转换
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Wei Zheng,Peigen Zhang,Li Yang,Jian Chen,Wubian Tian,Yamei Zhang,ZhengMing Sun
We report herein a fast and scalable approach to the synthesis of MO/CNT/Fe (MCI) hybrid nanostructures via microwave irradiation of MXene under ambient condition. The effect of three arcing materials, CNT, graphite (C), and carbon fiber (C f ), on the growth of carbon nanotubes on MXene-derived metal oxides were investigated. The resulted MCI nanostructures were tested as anodes in LIBs , all exhibiting better electrochemical performance than that of pristine Ti 3 C 2 . Remarkably, MCI-C f delivered reversible capacities of 430 mA h g −1 and 175 mA h g −1 at 1 A g −1 and 10 A g −1 , respectively, which is much higher than that of commercial graphite at high rates. The findings in this work open new exciting opportunities to developing hybrid electrode materials with high specific capacity for energy conversion and storage.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Yang Yuan,Youzhen Liu,Chenhui Li,Shi Feng,Qingquan Liu,Jia Huo
The electrocatalytic oxygen reduction reaction (ORR) plays an important role in renewable energy storage and conversion systems such as polymer electrolyte membrane fuel cells. However, design of high-performance cathode electrocatalysts is still required to speed up the sluggish kinetics of ORR. In this work, we develop a facile strategy to synthesize hierarchically porous N-doped carbon nanosheet networks with ultrafine encapsulated Fe 3 C and Fe-N x for ORR by consideration of thermodynamic (intrinsic and support effect) and kinetic (diffusion effect) parameters. The synthetic process is straightforward and sustainable and the hierarchically porous materials can be synthesized directly starting from raw materials and without any additional template. The as-designed catalyst exhibits excellent ORR catalytic performance in both acidic and basic media with much positive half-wave potential and good stability, which is comparable to commercial Pt/C. The excellent ORR performance may result from highly active Fe-N x sites and ultrafine encapsulated Fe 3 C, and the hierarchically porous nanosheet structure for accelerating mass diffusion and increasing exposure of the active site. This work provides a facile strategy for rational design and synthesis of highly active, hierarchically porous non-precious metal electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Guozhen Qin,Jianfeng Zheng,Yifan Li,Yatao Yang,Xingmin Liu,Xiaojin Han,Zhanggen Huang
Mainly exposed crystal facets and controllable morphology play a key role in the final performance of the preparation of specific nanomaterials . In the present study, a metal–organic framework pyrolysis method without adding solvent modifiers was developed. By adding CO in the calcination atmosphere to change atmosphere ratio, Fe 3 O 4 nanostructures are exposed with different crystal planes and evaluated their performance in NH 3 -SCR reaction. This study proves that SCR catalytic activity of Fe 3 O 4 nanocrystals is dependent on morphology and crystal facet. Compared with materials exposed (1 0 0), catalysts with more (1 1 1) show stronger deNO x performance. The preferential exposure of Fe 3 O 4 (1 1 1) crystal facets increases the concentration of adsorbed oxygen on the catalyst, showing higher surface acidity , and enhances the interaction among NO, O 2 and catalyst, which is conducive to SCR reaction. This is supported by DFT calculations . The results present a great application prospect in preparing nanomaterials with specific crystal structures to effectively treat pollutants.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 17
·14228-14239
·
IF 2.779
Liu Jieling,Yang Jiaji,An Shuyue,Wen Meiqi,Wang Xian,Gong Rongzhou,Nie Yan
Metal-organic framework (MOF) crystals have promising applications in a number of different fields, but the growth of MOF crystals with controllable morphology and high uniformity remains a major challenge. By taking the advantage of the synergistic effects of water molecules in the mixed solvent and polyvinylpyrrolidone (PVP) surfactants, this work demonstrates an approach for the preparation of NH 2 -MIL-88B(Fe) MOF crystals with both highly customizable size and aspect ratios and high uniformity. The effects of the concentration of water in the mixed solvent and the amount of PVP surfactants on the morphology and size of the MOF crystals were investigated. The morphology and crystalline properties were characterized by scanning electron microscopy and X-ray diffraction techniques. The data showed that through controlling the concentration of water in the solvent and the amount of the PVP surfactant, the size of the MOF crystals can be tuned rather widely, over 344–5.14 μm, while the aspect ratio of the crystals can be varied widely over 1.0–7.1. Possible mechanisms for such high tunability were discussed. As an example of potential applications, the complex permeability and permittivity of MOF-derived composites (25 wt%) were measured over a wide frequency range of 2–18 GHz. The parameters were then used to evaluate the potential for electromagnetic wave absorption. The results indicate that the composite with a thickness of only 1.2 mm exhibits a “− 10 dB” absorption bandwidth of 4.1 GHz and a minimum reflection of − 20 dB. Such bandwidth and reflection properties provide inspiration for future design of lightweight, broadband electromagnetic wave absorbers from the perspective of fine morphology control.
研究领域:
材料科学
·
化学工程
·
电磁学
✓ 已验证
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2018
·
IF 3.849
Weirui Chen,Zulin Zhang,Xukai Li,Dan Wu,Ying Xue,Laisheng Li
Fe-Cu-MCM-41/O 3 was first used as an alternative to O 3 to control disinfection by-products generation from chlorinated-disinfection of Br-containing Diclofenac. Accompanying with decrease of TOC , THMs and HAAs had an initial increase, reaching the highest at 30 min, then gradually decreased. Coupling Fe-Cu-MCM-41 with O 3 successfully enhanced TOC removal and inhibited bromate, THMs and HAAs formation in post-chlorination when compared with those in ozonation . Four kinds of THMs and six kinds of HAAs were detected. CHCl 3 was main Cl-THMs and CHBrCl 2 was main Br-THMs. CHCl 2 COOH was the dominant Cl-HAAs and CHClBrCOOH was main Br-HAAs. A converse Br-THMs order was observed in O 3 and Fe-Cu-MCM-41/O 3 pre-treatment. Fe-Cu-MCM-41 decreased ozone exposure, reducing the direct reaction of O 3 with Br − to form bromate. More DBPs precursors in Fe-Cu-MCM-41/O 3 were removed by ·OH. H 2 O 2 , which generated during pre-treatment process, reduced HBrO/BrO − to Br − , inhibiting both its reaction with Br-DBPs precursors and bromate formation. The pre-treatment process changed intermediates’ properties and hydrophilic DOM was the dominant component. Hydrophobic acids and transphilic DOM were the main chlorine consuming intermediates and had major contribution to DBPs formation. Fulvic-like intermediates was suggested as precursors of Br-DBPs. Fe-Cu-MCM-41/O 3 were suggested as a good alternative to O 3 pretreatment.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）