Nano Research
·
2020
·Vol. 14
·期 4
·1069-1077
·
IF 8.183
Su Panpan,Huang Wenjuan,Zhang Jiangwei,Guharoy Utsab,Du Qinggang,Sun Qiao,Jiang Qike,Cheng Yi,Yang Jie,Zhang Xiaoli,Liu Yongsheng,Jiang San Ping,Liu Jian
Defective electrocatalysts, especially for intrinsic defective carbon, have aroused a wide concern owing to high spin and charge densities. However, the designated nitrogen species favorable for creating defects by the removal of nitrogen, and the influence of defects for the coordination structure of active site and oxygen reduction reaction (ORR) activity have not been elucidated. Herein, we designed and synthesized a pair of electrocatalysts, denoted as Fe-N/C and Fe-ND/C for coordination sites of atomic iron-nitrogen and iron-nitrogen/defect configuration embedded in hollow carbon spheres, respectively, through direct pyrolysis of their corresponding hollow carbon spheres adsorbed with Fe(acac) 3 . The nitrogen defects were fabricated via the evaporation of pyrrolic-N on nitrogen doped hollow carbon spheres. Results of comparative experiments between Fe-N/C and Fe-ND/C reveal that Fe-ND/C shows superior ORR activity with an onset potential of 30 mV higher than that of Fe-N/C. Fe-ND sites are more favorable for the enhancement of ORR activity. Density functional theory (DFT) calculation demonstrates that Fe-ND/C with proposed coordination structure of FeN 4− x (0< x <4) anchored by OH as axial ligand during ORR, weakens the strong binding of OH* intermediate and promotes the desorption of OH* as rate-determining step for ORR in alkaline electrolyte. Thus, Fe-ND/C electrocatalysts present much better ORR activity compared with that of Fe-N/C with proposed coordination structure of FeN 4 .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2023
·
IF 3.8
Xunming Su,Zhong-Pan Hu,Jingfeng Han,Yingxu Wei,Zhongmin Liu
Developing highly efficient methods to selectively incorporate active metal sites into the zeolite framework is crucial for the large-scale utilization of metal-zeolites in various catalytic reactions including alkane conversion. Herein, ferrous gluconate is developed as an efficient metal precursor to embed Fe atoms into the MFI siliceous zeolite framework. The crystallization time and Si/Fe ratio are systematically investigated. It is revealed that the ferrous gluconate is well soluble and stable under alkaline conditions, allowing ferrous gluconate to participate in the whole crystallization course of zeolite. Multiple characterizations demonstrate that the tetrahedrally coordinated Fe atoms are selectively incorporated into the MFI siliceous zeolite framework (Fe-MFI). A catalytic test in propane dehydrogenation shows that the optimized Fe-MFI zeolite possesses high activity, propylene selectivity, and durability. This study opens an efficient strategy to incorporate isolated Fe atoms into the zeolite framework.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2025
·
IF 5.1
Mohammadreza Rostami,Biao Yang,Xiaochuan Ma,Sifan You,Jin Zhou,Meng Zhang,Xuefeng Cui,Haiming Zhang,Francesco Allegretti,Bing Wang,Lifeng Chi,Johannes Barth
n-Armchair graphene nanoribbons (nAGNRs) are promising components for next-generation nanoelectronics due to their controllable band gap, which depends on their width and edge structure. Using non-metal surfaces for fabricating nAGNRs gives access to reliable information on their electronic properties. We investigated the influence of light and iron adatoms on the debromination of 4,4”-dibromo-p-terphenyl precursors affording poly(para-phenylene) (PPP as the narrowest GNR) wires through the Ullmann coupling reaction on a rutile TiO2(110) surface, which we studied by scanning tunneling microscopy and X-ray photoemission spectroscopy. The temperature threshold for bromine bond cleavage and desorption is reduced upon exposure to UV light (240-395 nm wavelength), but the reaction yield could not be improved. However, in the presence of codeposited iron adatoms, precursor debromination occurred even at 77 K, allowing for Ullmann coupling and PPP wire formation at 300-400 K, i.e., markedly lower temperatures compared to the conditions without iron adatoms. Furthermore, scanning tunneling spectroscopy data reveal that adsorbed PPP wires feature a band gap of ≈ 3.1 eV.
研究领域:
材料科学
·
表面化学
✓ 已验证
DOI
PubMed
高影响因子
CHINESE PHYSICS LETTERS
·
2024
·Vol. 41
·期 12
·128401
·
IF 3.5
Xi Wen,Yang Qin,Yu Hao,Geng Chang,Kai Huang,Ming Lei,Xiaojun Shen,Yong He,Xuchao Pan,Yufeng Wu
Electromagnetic wave-absorbing materials play a crucial role in modern electronics, particularly in stealth and communication technologies. Carbon-based materials demonstrate considerable potential for the development and use of effective wave-absorbing substances, attributed to their complex structure, lightweight nature, excellent corrosion resistance, and affordability. Notably, nitrogen-doped carbon-based two-dimensional (2D) materials exhibit a more pronounced depletion effect on electromagnetic waves owing to their increased specific surface area and numerous polarization states. This article presents the successful synthesis of nitrogen-doped carbon (NC) 2D flakes using a hydrothermal method. In addition, single Fe atoms were successfully incorporated onto their surfaces, forming Fe@NC. The wave-absorbing capabilities of the Fe@NC samples were considerably improved, achieving a minimum reflection loss (RLmin) of −69.22 dB at 11.48 GHz and an effective absorption bandwidth of 5.79 GHz. The enhancement in electromagnetic wave absorption is attributed to the synergistic effects of magnetic loss, relaxation processes, dipole polarization, and electrical conduction loss. The successful synthesis of Fe@NC opens up new avenues for the development of atomically dispersed wave-absorbing materials.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
iScience
·
2023
·
IF 5.8
Jian Du,Yunxuan Ding,Yu Guo,Licheng Sun,Fei Li
Carbon-supported iron-cobalt bimetallic electrocatalysts usually exhibit robust catalytic activity toward the oxygen evolution reaction (OER). However, the spatial isolation of Fe species at atomic level on cobalt-carbon solid remains a great challenge for practical catalytic applications in the OER. Here, we report the fabrication of CoFe bimetal porous carbon electrocatalysts by pyrolysis of molecularly defined iron complexes such as FePc (Pc = phthalocyanine) and Fe(acac) 3 pre-encapsulated in the cavities of zeolitic imidazolate framework (ZIF)-67. With this unique strategy, high-loading atomic Fe nanoclusters (Fe-ACs) and Fe single atoms (Fe-SAs) were supported on Co/NC hybrids relying on the size of the molecular Fe precursors. The former exhibited superior OER performance to the single Fe atom-decorated Co/NC, as well as other ZIF-67-derived electrocatalysts. Theoretical modulation suggests Co as the OER active site for Fe-ACs@Co/NC at the in situ -formed FeOOH-ACs/Co 3 O 4 interface, while Fe was proposed as the active site for Fe-SAs@Co/NC.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
RARE METALS
·
2025
·
IF 11
Wu Jing,Rong Jian,Chen Wang-Yi,Wang Chao-Sheng,Feng Chu-Jun,Ao Huai-Sheng,Zhu Cheng-Zhang,Zhang Yu-Zhe,Li Zhong-Yu
Regulating the electronic structure and oxygen-containing intermediates adsorption behavior on Fe-based catalysts is of great significance to cope with the sluggish oxygen reduction reaction (ORR) kinetics, but it still remains a great challenge. In this work, Fe atom clusters (Fe AC ) modified by high-density Cu single atoms (Cu SA ) in a N,S-doped porous carbon substrate (Fe AC /Cu SA @NCS) is reported for enhanced ORR electrocatalysis. Fe AC /Cu SA @NCS exhibits excellent ORR performance with a half-wave potential ( E 1/2 ) of 0.911 V, a high four-electron process selectivity and excellent stability. The ORR performance is also verified in the Fe AC /Cu SA @NCS-based Zn-air battery, which shows a high peak power density of 192.67 mW cm −2 , a higher specific capacity of 808.3 mAh g −1 and impressive charge–discharge cycle stability. Moreover, density functional theory calculations show that Cu single atoms synergistically modulate the electronic structure Fe active atoms in Fe atomic clusters, reducing the energy barrier of the rate-determining step (i.e., * OH desorption) on Fe AC /Cu SA @NCS. This work provides an effective way to regulate the electronic structure of Fe-based catalysts and optimize their electrocatalytic activity based on the introduction of a second metal source. Graphical abstract
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Zhendong Ma,Jianshuo Zheng,Chenyue Wang,Pengli Lei,Qiu Zhuang,Weijin Li,Aming Xie
Dielectric loss and magnetic loss are two necessary factors in electromagnetic wave absorption, but there are few works that can study magnetic factors alone because of the limitations of the material itself. This work achieved the transformation from a nonmagnetic polymer (PFc-1) to a superparamagnetic polymer (PFc-3) by introducing alkyne units to regulate the valence state of iron atoms in the ferrocene unit. It also accomplished the transition of wave-absorbing properties from nonexistent to present. The extremely low dielectric loss of the polymer itself also provides a good background for studying magnetic losses. After characterization, the maximum reflection loss of PFc-3 under the action of exchange resonance reaches −31.7 dB. Through density functional theory (DFT) calculations, we can speculate on the specific mechanism of exchange resonance in PFc-3: under the influence of specific external sources, the single-electron energy level structure of Fe changes. The frequency jumps, creating a resonance. This work opens up a perspective for the application of magnetic regulation in the field of electromagnetic absorption.
研究领域:
材料科学
·
电磁学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Ruiling Sun,Guilong Yan,Xunlong Zhang,Zhenyu Li,Jingyu Chen,Li Wang,Yuanpeng Wu,Yiqun Wang,Han Li
The nanomaterials with multiple components and various heterogeneous interfaces have been considered as preferred efficient electromagnetic wave (EMW) absorbers. In this paper, Fe atoms were bonded to a zeolitic imidazole framework (Fe-ZIF) and Fe-ZIF-derived hollow porous carbon nanofibers (Fe-HPCNFs) were prepared by the microfluid electrospinning method. The EMW absorption properties of carbon nanofibers (CNFs), Fe-ZIF-derived carbon nanofibers (Fe-CNFs), and Fe-ZIF-derived hollow porous carbon nanofibers (Fe-HPCNFs) were systematically studied. The results showed that Fe-HPCNFs has the best performance, when the thickness was only 2.0 mm, the Fe-HPCNFs achieved a minimum RL loss of −46.9 dB at 17.38 GHz, with an effective absorption bandwidth of 3 GHz. The Fe-HPCNF is a flexible, ultralightweight, self-supported material as a potential high-efficiency EMW absorber.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Ziyuan Xiu,Wei Mu,Xin Zhou,Xiaojun Han
The electrocatalytic N 2 reduction reaction (NRR) is expected to supersede the traditional Haber-Bosch technology for NH 3 production under ambient conditions. The activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst, correct electron transfer direction, and electron tunneling distance between bare electrode and active sites. By coupling the chemical vapor deposition method with the poly(methyl methacylate)-transfer method, an ultrathin sandwich catalyst, i.e., Fe atoms (polarized electric field layer) sandwiched between ultrathin (within electron tunneling distance) BN (catalyst layer) and graphene film (conducting layer), is fabricated for electrocatalytic NRR. The sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal exposure. The sandwich electrocatalyst NRR system achieve NH 3 yield of 8.9 μg h −1 cm −2 and Faradaic Efficiency of 21.7%. The N 2 adsorption, activation, and polarization electric field changes of three sandwich catalysts (BN-Fe-G, BN-Fe-BN, and G-Fe-G) during the electrocatalytic NRR are investigated by experiments and density functional theory simulations. Driven by applied voltage, the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electrocatalytic NRR.
研究领域:
材料科学
·
电化学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2022
·
IF 6.556
Xiaofang Chen,Min Feng,Xiaoyi Xie,Yi Zhang,Jie Zhang,Xiupei Yang
Single-atom catalysts have attracted enormous research interest in the field of catalysis owing to their remarkable catalytic activity, excellent stability and outstanding atom utilization. Herein, a new single atom based on single Fe atoms on fluorine-doped (Fe–SAs@FNC) ultrathin carbon nanosheets was successfully synthesized by a polymer-assisted heating method. Experimental evidence showed that the resultant Fe–SAs@FNC with Fe–N 4 sites exhibits superior peroxidase-like activity, which oxidizes the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue product in the presence of hydrogen peroxide (H 2 O 2 ). Based on this, an ultrasensitive and highly selective colorimetric detection method for p -phenylenediamine (PPD) in hair dyes and PPD in hair after dyeing was established, which had a wide linear range (0.2–50 μM) and low detection limit (0.07 μM). This method shows satisfactory sensitivity and selectivity.
研究领域:
材料科学
·
分析化学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Enxiang Ren,Xing Zhang,Guo-Ping Lu,Muhammad Sohail,Jun Hu,Zhong Chen,Daidi Fan,Yamei Lin
The poor activity and specificity of nanozymes limit their applications in many fields owing to their low density of active sites, inhomogeneous atomic composition, and complex structure. To overcome these issues, a single iron-anchored carbon material, Fe/CN-800-A, with FeN2 sites has been fabricated, which exhibited exclusive oxidase-like activity. The mechanisms of N-coordination-number-regulated enzymatic activity and specificity of the composite were also explored to elaborate the working principle. The FeN2 sites in Fe/CN-800-A exhibited higher oxidase-like activity and specificity than the FeN4 sites in Fe/CN-700, owing to their lower energy barriers for O2 absorption and the decomposition of H2O2 into O2. These findings provide a theoretical basis for the rational design of nanozymes with high oxidase-like activity and specificity. The fabricated nanocomposites have commercial potential for effective chlorpyrifos detection and antibacterial applications due to their unique structural traits and high efficiency.
研究领域:
材料科学
·
分析化学
·
生物技术
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Rui Li,Xiaoxuan Sun,Ling Yang,Panpan Zhao,Jianguo Zhao,Jiao Ding,Shuangli Wu,Chenguang Li,Hao Liu,Shaojun Dong
Curbing the rapid structural degradation of Fe-N-C materials during acidic oxygen reduction reaction (ORR) has been a long-standing challenge in commercializing ORR-based device with long-term stability. Herein, structural deactivation is effectively inhibited via optimizing interfacial Fe-O dipole by introducing the second Fe atom. The elaborately designed Fe double-atom catalysts (Fe DACs), featuring Fe₂N₆ motifs, induce a shift in O 2 adsorption geometry from end-on to bridge configurations for reorienting interfacial Fe-O local dipole ( μ L ) to relieve demetallation. Hence, Fe DACs achieve enhanced operational stability by 10.4 and 31.2 times over Fe 1 N 4 in both single electrode systems and H 2 O 2 -O 2 fuel cells. In-situ measurements and theoretical simulations reveal the origin for the suppression of structural degradation is due to that the optimized Fe-O μ L reduces the tensile stress exerted by the electric field on the Fe-N bond, coupled with intrinsically stable electronic structure in Fe₂N₆ during dynamic structural evolution to stabilize Fe-N bonds.
研究领域:
催化化学
·
电化学
·
材料科学
·
能源化学
·
表面科学
✓ 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）