International Journal of Electrochemical Science
·
2023
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IF 1.5
Yiqi Cui,Shuaikang Ying,Hongzhong Cai,Yan Wei,Changyi Hu
Carbon-supported platinum (Pt) for oxygen reduction reaction plays an important role in the operation of direct methanol fuel cells (DMFCs). However, complete oxidation of ethanol is difficult due to the low chemical activity of Pt / C. Herein, novel highly active Pt-Co/C nanoparticles with controllable chemical composition and particle size are prepared via a thermal reduction method. The results revealed that the catalyst (particle size: 2–4 nm) is characterized by a good size monodispersity, and exhibits satisfactory chemical activity. The nanoparticles were also characterized by an accurate and maintained stoichiometry ratio, resulting in improved electrocatalytic activity and anti-poisoning ability of the carbon-supported Pt.
研究领域:
材料科学
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电化学
·
纳米技术
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DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Jie Huang,Wenhao Yang,Sen Zhang,Jingjie Luo,Changhai Liang
Catalytic hydrogenation of adiponitrile to hexamethylenediamine (HMDA) via alkali-free processes is essential to produce high-value downstream chemicals. In this work, we synthesized a series of Co@C CNT x catalysts using CNT promotion to strength the carbon skeleton derived by ZIF-67. Compared to the Co@C without CNT promotion, great enhancement of HMDA yield was achieved by Co@C CNT x . Characterizations suggested that CNT in the precursor modified the crystallization of the active Co centers as well as the surface composition in the Co@C CNT x . Strong Co-carbon interaction was formed via Co-N coordination caused by the facilitated re-dispersion of N- containing functionalities. The ethanol contact angle on Co@C CNT x was changed for better mass transfer and diffusion of reaction liquid on the catalyst. As a final result, the oxidation of cobalt sites was greatly suppressed in Co@C CNT 0.3 and Co@C CNT 0.5 , which was proved an essential factor for their fast reaction rates. 88 % yield of HMDA with the rate of 4.5 mol HMDA /mol Co /h was reached under a much higher utilization rate of Co center.
研究领域:
化学工程
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催化化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
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IF 13.3
Xiaoqian Hao,Shengjun Xu,Yan Huang,Shuanglong Ma,Boqiang Gao,Jia Song,Jingzhen Wang,Sihui Zhan
Molybdenum disulfide serves as an ideal support for single atom catalysts (SACs), offering not only coordination elements but also abundant active sites, such as surface defects and vacancies. Herein, a novel Co-SAC (MoSO-Co-C) containing a four-coordinated configuration (Mo-Co-C 3 ) is designed and synthesized, in which the carbon intercalation is utilized to regulate sulfur vacancies for anchoring the Co atom. The introduction of Co atoms and C intercalation significantly enhances the E ads between catalyst and peroxymonosulfate (PMS), favoring the formation of metastable intermediates. The k obs of sulfamethoxazole (SMX) removal for MoSO-Co-C is 9.2 times and 1.8 times higher than those of catalysts without Co or C intercalation. SMX is removed mainly by electron transfer pathway, wherein SMX and PMS act on the same Co site of MoSO-Co-C, and electrons are transferred from SMX to MoSO-Co-C and eventually to PMS. The MoSO-Co-C demonstrated excellent SMX degradation in the diverse water matrices, and the removal efficiency of SMX maintained above 95 % after 72 h of continuous degradation. This study provides new insights into the design of transition metal-based SAC and in-depth understanding of PMS activation mechanism.
研究领域:
环境科学
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催化
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水处理
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yishu Qiu,Zheng Hu,Hui Li,Qianqian Ren,Yanan Chen,Shi Hu
The commercial catalysts for oxygen reduction reaction (ORR) are highly dependent on the scarce and expensive Pt to achieve high activity and reasonable durability, especially for the fuel cells used in automobiles. Ag alloys have been proposed as promising candidates for non-Pt ORR catalysts in alkaline media, with reasonably high activity at significantly lower cost. Herein we demonstrate the synthesis of Ag/Co/C hybrid electrocatalyst for ORR via radiative flash Joule heating. Unlike the previously reported solid-solution structure of the quenched immiscible alloys by flash Joule heating, the large immiscibility gap in the liquid state of the Ag-Co alloy prevents the formation of solid solution. The hybrid catalyst exhibits a specific activity 40 times and a mass activity 52 times higher than that of the pristine Ag/C at 0.8 V vs. RHE in alkaline media, and its tolerance to methanol and ethanol is superior to that of commercial Pt/C. The enhanced activity and good stability are attributed to the enhanced oxygen adsorption energy on silver due to the strong interaction between silver and cobalt.
研究领域:
材料科学
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电化学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2026
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IF 6.3
Hongwei Zhou,Ying Lin,Yongzhen Ma,Zhao Meng,Haibo Yang
To obtain high-performance electromagnetic wave (EMW) absorption materials with a broad effective absorption bandwidth (EAB), structural design has proven to be an effective strategy. In this investigation, Co/C@carbon nanofibers (Co/C@CNFs) derived from metal-organic frameworks (MOFs) were integrated with graphite oxide (GO) nanosheets, and Co/C@CNFs/GO aerogels were prepared through unidirectional freeze-drying followed by heat treatment. The resulting aerogels exhibit a unique directional channel structure that increases their contact area with air, thereby improving impedance matching. The Co/C@CNFs/GO aerogels demonstrate exceptional EMW capabilities, primarily due to the multiple heterogeneous interfaces and the synergistic electromagnetic loss mechanisms generated by the interactions among GO nanosheets, CNFs, and Co particles. The results reveal that Co/C@CNFs/GO-2 achieves remarkable EMW absorption with a maximum EAB of 10.0 GHz, covering both the X and Ku bands, thanks to its directional channel structure and complete conductive network. Moreover, the aerogels exhibit excellent radar cross-section attenuation and superior thermal insulation. This work provides a reliable strategy for synthesizing multifunctional carbon-based aerogels materials with efficient EMW absorption, offering broad potential for applications in electromagnetic protection, thermal management, and related fields.
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高影响因子
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
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2016
·Vol. 44
·期 2
·224-231
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IF 0.566
Chang-Ping RUAN,Ke-Long AI,Le-Hui LU
Magnetic adsorbents have recently been extensively investigated and applied in the field of water purification, because of their magnetic characters which are advantageous for the separation and recycle of these materials. Unfortunately, common magnetic materials are unstable and prone to dissolution in acid environment, thus limiting their practical applications in wide pH range, particularly in acidic condition. Therefore, it is highly imperative to exploit a novel magnetic adsorbent that is acid-resistant, to simplify separation process during the water purification. In present work, an acid-resistant magnetic Co/C nanocomposite was synthesized by using ZIF-67 as both template and precursor. The ZIF-67 was carbonized in an argon atmosphere at 800 °C for 1 h, and then treated with acid. Upon calcination at an appropriate temperature in inert atmosphere, the generated Co nanoparticles were uniformly wrapped by graphite layers, due to the graphitization of carbon upon the catalysis effect of Co. The formed graphite layers were able to protect the Co particles from oxidation and acid environment, thus resulting in the generation of an acid-resistant magnetic adsorbent that can be applied in a wide pH range (pH 1–13). Remarkably, the as-synthesized magnetic Co/C nanocomposite demonstrated excellent adsorption performance towards two typical organic dyes (rhodamine B and malachite green) over a wide pH range. The adsorption isotherms of rhodamine B and malachite green on Co/C nanocomposite were well fitted with the Langmuir model. Impressively, the maximum adsorption capacities towards rhodamine B and malachite green were estimated to be 400.0 and 561.8 mg g −1 , respectively, far exceeding many previously reported adsorbents. Moreover, the adsorbent could be easily regenerated by washing with ethylene glycol (EG), suggesting its excellent reusability. Even after 5 cycles of reuse, no obvious capacity degradation was observed. Furthermore, practical application of the magnetic adsorbent was demonstrated by the removal of organic dyes from domestic wastewater with a superior removal efficiency of higher than 97%.
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DOI
高影响因子
Water
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2022
·Vol. 14
·期 14
·2248
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IF 3.53
Guowei Pang,Min Ji,Zhuoran Li,Zhengwu Yang,Xiaojie Qiu,Yingxin Zhao
In this work, an efficient cage-core peroxymonosulfate (PMS) catalyst was synthesized by applying an electrospinning–calcination process to the cobalt–zeolitic imidazole framework (ZIF-67) crystals for the catalytic degradation of dimethyl phthalate (DMP). The morphology and surface properties of the synthesized materials (ZIF-67, Z600 and ZP400/600/800) were well characterized. ZP600 showed great performance for the catalytic degradation of DMP in the initial pH range of 7.5–10.5. The removal rate of DMP could reach 90.4% in 60 min under optimum dosages of reagents (catalyst = 0.1 g/L, PMS = 0.5 mM, DMP = 6 ppm), and the mineralization degree of contaminant could reach 65%. By quenching experiments, it was determined that sulfate radical (SO4−·) and hydroxyl radical (·OH) dominated the degradation process. Moreover, due to the good magnetism, ZP600 could be easily separated from liquid and showed great reusability in five-cycle reaction experiments. Surprisingly, with the cover of cage-like polyacrylonitrile (PAN) fibers, the cobalt leaching amount of ZP600 decreased by about 87%. This study would expand the application of the electrospinning process in the development of functional materials for water purification.Keywords:elctrospinning;ZIF-67;peroxymonosulfate;cobalt leaching control
研究领域:
环境科学
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材料科学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Jun Yu,Bin Hu,Pengfei Nie,Xiaohong Shang,Boshuang Zhang,Zhaoyu Tang,Jianmao Yang,Jianyun Liu
Norfloxacin (NX), as one of the most widely used antibiotics, is becoming a potential pollutant in water. Here, the cobalt-decorated nitrogen-rich carbon material containing abundant carbon nanotubes (Co@C-NCNTs) was synthesized by pyrolysis of the Co,Zn bimetal organic frameworks (Co,Zn-MOF). The introduction of Zn led to the formation of abundant CNTs with high aspect ratio and high N-doping in the carbon metrix. The obtained Co@C-NCNTs catalyst was applied to boost non-radical catalysis of peroxymonosulfate for NX degradation with high efficiency. The release of cobalt was greatly inhibited by Co-N interaction and carbon layer protection. The CNTs amount in Co@C-NCNTs and its catalytic activity were tunable with the Zn/Co ratio. At the optimal Zn/Co ratio, the derived Co@C-NCNTs delivered 92% removal of NX in 30 min, significantly higher than the single Co-MOF based catalyst. Free radical quenching experiments and electron paramagnetic resonance demonstrated the singlet 1 O 2 -dominated degradation process of NX accompanied by the •OH and S O 4 − effect. The electrochemical characterization verified that the electron transfer in the PMS system is greatly enhanced due to the presence of Co@C-NCNTs.
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DOI
高影响因子
CARBON
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2022
·
IF 11.307
Xue Zhang,Xuelei Tian,Chang Liu,Jing Qiao,Wei Liu,Jiurong Liu,Zhihui Zeng
Metal-organic frameworks (MOFs) have attracted more and more attentions for preparing electromagnetic wave (EMW) absorption materials because of the porous structure , high specific surface area, and designable configuration. Herein, a series of MOF-74 derived nanocomposites were synthesized by hydrothermal process and subsequent carbonization . The EMW absorption performance and the functions of each component were investigated in depth. Moreover, the inherent EMW absorption mechanisms were comprehensively revealed. Benefiting from the synergistic effect of constituents and microstructure, the MnCo-MOF-74 derived MnO/Co/C nanocomposites delivered a minimum reflection loss value of −68.89 dB at the thickness of 2.64 mm and an effective absorption band of 5.3 GHz at the thickness of 2.3 mm. The high EMW absorption performance was ascribed to the optimized impedance matching and multiple attenuation mechanisms including interfacial and dipole polarization loss, magnetic loss, conductive loss, and multiple scatterings capability. This study shed light on exploring high-efficiency MOF-based EMW absorption materials with rational design of components and structure.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
CARBON
·
2023
·
IF 10.9
Jiali Chen,Lei Wang,Bin Shen,Wenge Zheng
Recently, highly efficient electromagnetic attenuation materials are crucial for the development of modern electronics and telecommunications. Meanwhile, biomass-derived carbon materials have attracted widespread attention due to their availability and renewable characteristics. In this study, a composite with Co/C particles embedded in carbon networks was synthesized by pyrolysis of cotton fiber coated with ZIF-67, which are showing tunable and higher electromagnetic interference (EMI) shielding effectiveness (SE) than pure carbon networks. The remarkable performance originated from the aligned carbon networks and the Co/C particles connected by the carbon networks. The former can achieve the regulation of EMI SE by changing the angle between the fiber orientation direction and the direction of the incident EM-wave electric field, while the latter can play a role in catalytic graphitization and enhance the shielding performance. When decreasing the pyrolysis temperature and filling the composite powder with 30 wt% in the paraffin matrix, the minimum reflection loss (RL min ) can reach −58.8 dB at 5.12 mm. In addition, the effective absorption band (EAB) of the composite can cover the C-Ku band by adjusting the thickness from 3 to 7 mm. This work provides a potential guideline for efficient biomass-based electromagnetic attenuation materials.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2025
·
IF 6.3
Zhihui Xu,Jing Li,Xiaoling Peng,Shan Tao,Jingcai Xu,Bo Hong,Xinqing Wang
Developing high-performance microwave absorbers with strong absorption, broad bandwidth, and small thickness remains challenging. Herein, we report a novel strategy for constructing hierarchical LaFeO₃/Co/C composites by in-situ growing ZIF-67 on biomimetic corncob-like LaFeO₃ (LFO) followed by pyrolysis. The hollow architecture of LFO, featuring vertically aligned nanosheet arrays, provides abundant nucleation sites and facilitates multiple reflections and scattering of incident microwave. The synergistic effect between the dielectric LFO and magnetic Co/C significantly improved the impedance matching and attenuation. The optimized composite exhibited exceptional minimum reflection loss (RL min ) of -54.9 dB at 1.5 mm and a broad effective absorption bandwidth of 5.44 GHz at 1.7 mm (almost covering the entire Ku-band). The performance is attributed to the enhanced impedance matching, synergistic dielectric-magnetic loss, and intensive interfacial polarization. This work provides a valuable insight for designing high-efficiency EMW absorbers through morphological and compositional regulation.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
·
IF 13.3
Xueai Li,Kexin Jin,Xiangyan Qu,Yuning Shi,Chunsheng Wang,Wanchun Guo,Kesong Tian,Yahui Wang,Haiyan Wang
The dispersion of diverse magnetic metallic in a single particle plays an important role in microwave absorption; however, its contribution is not clear due to the challenge of controllable synthesis of magnetic bimetallic nanoparticles in one micro/nanostructure. Herein, a series of magnetic bimetallic nanoparticles separately confined growth in a hollow multi-shell microsphere with proper impedance matching characteristic were prepared, which can be used as theoretical models to elucidate magnetic coupling effect between diverse magnetic metallic nanoparticles in a single particle on electromagnetic attenuation. The coupling effect of magnetic Co and Fe nanoparticles dispersed in different shell effectively enhance the microwave absorption performance of void@Fe@SiO 2 /Co/C particles with minimum reflection loss (RL min ) of −62.3 dB (RL=-20 dB, 99 % absorption) at a thickness of 2.05 mm, provoking the maximum radar cross-section (RCS) reduction value of perfect electric conductor (PEC) 37.37 dBm 2 . Meanwhile, broad effective bandwidth (EBW, RL≤-10 dB, ≥90 % absorption) response of 7.04 GHz at a thickness of 2.44 mm was achieved. These findings can provide guidance for the designation of novel magnetic broadband microwave absorbing materials (MAMs).
研究领域:
材料科学
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电磁学
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DOI
高影响因子
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