JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Shumeng Wu,Caixia Feng,Bingbing Fan,Yonghong Li,He Wang,Yanmei Zhou
Heteroatoms-doped hierarchical porous carbons have attracted considerable interest owing to their efficient utility in supercapacitors . However, the increase of defects tends to sacrifice the electrical conductivity of carbon materials. Therefore, it is of great significance to build a good conductive network by increasing the graphitization degree of porous carbons . Here, this study reports the use of serine phosphate protic salt ([Seri][H 2 PO 4 ]), Pluronic F127 and cobalt nitrate to engineer the N/O/P co-doped hierarchical porous graphitic carbon materials. The Co 2+ catalyzes the graphitization of porous carbons under high temperature. A large number of mesopores, highly doped heteroatoms (O: 4.2 wt%, N: 4.07 wt%, P: 0.81 wt%) and conductive carbon skeleton boost the ultrafast transport of electrons and ions, resulting in high specific capacitance, wide operating voltage and outstanding rate performance. The symmetric supercapacitor assembled in KOH electrolyte shows good frequency response with the scan rate up to 1.5 V s −1 on the working voltage of 0–1.3 V. At the same time, when the power density reaches up to 21.3 kW kg −1 , its energy density remains 8.74 W h kg −1 . Furthermore, the symmetric supercapacitor delivers a high energy density of 81.42 W h kg −1 at the power density of 875 W kg −1 with an ultrahigh working voltage of 3.5 V in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4 ) electrolyte. More promisingly, all-solid device based on the optimized sample exhibits outstanding flexibility, which greatly broadens its practicability. This work marks the importance of the balance between porous structure, heteroatom doping and high conductivity for advanced supercapacitors .
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DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2023
·
IF 2.1
Wenchao Zhang,Qiang Fu,Qixin Yuan,Han Li,Dong Yue,Yu Feng,Qingguo Chen,Jinghua Yin
Polyimide (PI) film have been synthesized and used extensively in energy transmission, wind power generation, new energy vehicles, lidar, and high-power weapons, et al. Nevertheless, it is still challenge to further improve the breakdown strength and dielectric constant of PI film. After the powders of Al0.5xNb0.5xSi1-xO2 (NASO (x mol%)) have been fabricated, it was analyzed that the effect of doping elements Al3+ and Nb5+ on the surface chemistry and microstructure of the NASO powder. And then a small amount of NASO powder was polymerized in situ with PI matrix material, and the effects of NASO on dielectric properties and breakdown strength of the NASO/PI composites were analyzed. The results showed that the introduction of the doping elements Al3+ and Nb5+ favors could be conductive to the formation of oxygen vacancies on the surface of the NASO particle, which improved the surface activity and chemical reactivity of the NASO particle. The PI matrix can efficiently capture additional charges and enhance the insulating characteristics of the NASO/PI composite by properly doping NASO fillers with specific defect concentrations. In the results the breakdown strength of 1 vol% NASO (1 mol%)/PI composites reaches 334.38 kV/mm, which is a 19.6% higher than that of PI. Because the traps in the fillers capture and suppress the carrier transport to enhance the insulating properties of the composites. This work offers a novel synthesis method to simultaneously produce polymer dielectrics with high insulation and high polarization.
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2013
·
IF 2.39
Shaobo Shi,Yu Yang,Jianping Xu,Lan Li,Xiaosong Zhang,Guo-Hua Hu,Zhi-Min Dang
Zn 1− x Co x O (0 ⩽ x ⩽ 0.06) nanorods were fabricated by hydrothermal method. The effect of Co doping on the morphology, crystalline structure, optical and magnetic properties of the samples was investigated. The length of obtained ZnO nanorods increases with the increasing Co concentration. Based on the results of X-ray diffraction and Raman spectra, it is confirmed that a small amount of Co ions are incorporated into ZnO lattice. The segregated phase of Co 3 O 4 was detected at x > 0.01. The absorption and photoluminescence spectra reveal the d–d electronic transitions of tetrahedrally coordinated Co 2+ in ZnO host. Co doping induces fluorescent quenching of the visible emission bands related to surface states and defect states in the Co-doped ZnO nanorods. Weak room temperature ferromagnetism was observed in the samples with x = 0.01 and then paramagnetic characteristics of the samples with x > 0.01.
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DOI
高影响因子
MATERIALS LETTERS
·
2019
·
IF 3.019
Qilei Wu,Jun Wang,Huihui Jin,Tingyu Yan,Guoqiang Yi,Xiaogang Su,Wei Dai,Xiang Wang
Nanoporous carbon (NPC) composites embedded with magnetic nanoparticles have been widely studied for applications in microwave absorption. Herein, highly porous rambutan-like carbon composites decorated with controllable carbon nanotubes (CNTs) and Co nanoparticles were synthesized through a thermal decomposition of Co-doped zeolitic imidazolate frameworks-8 (ZIF-8) under different temperatures. The MOF-derived carbon nanocomposites with the cobalt content accounting for 30% of the total mass of cobalt and zinc, carbonized at 700 °C, exhibited excellent microwave absorption property of −30.2 dB. Characterizations exhibit that the in-situ generated Co nanoparticles are uniformly embedded into NPC matrix, which are surrounded by highly graphitized CNTs. The research presents a facile and promising route for rapid mass production of metal-doped NPC/CNTs composites for high-efficiency microwave absorption.
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DOI
高影响因子
OPTICAL MATERIALS
·
2016
·
IF 2.183
Pande Zhang,Benxue Jiang,Jintai Fan,Xiaojian Mao,Long Zhang
Cr and Nd co-doped laser ceramics, as the potential gain materials in inertial confinement fusion (ICF), have been widely investigated. And the study on valence states of chromium ions is important. The effects of sintering additives and annealing atmosphere on the valence state of chromium were studied in detail, and the results shown that the Cr valence states were demonstrated to be Cr 2+ and Cr 3+ ions in HIP-sintered Cr(0.2 at.%), Nd(0.8 at.%): LuAG laser ceramics. And the intensity of the near-infrared absorption band caused by Cr 2+ ions was attenuated with the decreasing SiO 2 concentration and increasing MgO amount. The near-infrared absorption could be eliminated by annealing in air. And the transformation of valence states of Cr ions in the Cr,Nd:LuAG ceramics were also confirmed by electron paramagnetic resonance and X-ray photoelectron spectroscopy.
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 10
·13941-13947
·
IF 2.478
Liu Ying,Cao Bo,Zhang Xu,Luo Rong,Luo Chunhua,Lin Hechun,Peng Hui
Layered Co(OH) 2 has been regarded as a potential candidate for pseudocapacitor electrode material, but it is limited by its poor conductivity and low surface area. Herein, carbonated multi-walled carbon nanotubes (MWCNTs-COOH) were used to improve the conductivity of α-Co(OH) 2 nanocomposites. α-Co(OH) 2 nanoflowers were successfully grown and tangled with MWCNTs-COOH to form a randomly oriented network structure mediated by ammonia using water-methanol as co-solvent at room temperature. The capacitance performances of the obtained α-Co(OH) 2 @MWCNT-COOH composites were investigated to find that MWCNT-COOH improved the specific capacitance efficiently. Especially, in the presence of 20% in mole of MWCNT-COOH, the composite gave rise to the high specific capacitance of 1027 F/g at the current density of 2 A/g with good cycle stability, whose specific capacitance remained 78% of its original even after 5000 cycles at 30 A/g current. The large surface area and strengthening the conductivity of the composites lead to the improvement of efficiency in charge/discharge process.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Qingqing Han,Kunjie Zhu,Ting Jin,Zewen Yang,Yuchang Si,Yijing Wang,Lifang Jiao
Sn is considered as a promising anode for lithium-ion batteries due to its low cost and high theoretical capacity (992 mA h g −1 with Li 4.4 Sn). However, the volume expansion (∼300%) during lithiation/delithiation process can result in the continuous pulverization of active materials and exfoliation from current collector, deteriorating the capacity and cycling performance. Here Co/Co 3 SnC 0.7 N-doped carbon nanofibers are successfully synthesized by a feasible electrospinning method. And the materials as the self-standing anode for lithium-ion batteries reveal a high-rate performance as delivering reversible capacities of 480 mA h g −1 at 100 mA g −1 and 290 mA h g −1 at 2000 mA g −1 . In addition, the specific capacity can still maintain 320 mA h g −1 at 500 mA g −1 even after 900 cycles, showing the outstanding cycling stability. The inactive metal Co and one-dimensional N-doped carbon nanofibers synergistically promote the electrochemical performance of the Sn-based anode by inhibiting the aggregation of the nanoparticles and buffering volume variation during lithiation/delithiation process.
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DOI
高影响因子
MATERIALS SCIENCE-POLAND
·
2020
·Vol. 38
·期 3
·502-507
·
IF 0.911
Meihua Hu,Ning Bi,Mingming Liu,Guangjin Gao,Shangsheng Li,Taichao Su
The improved TiB2 ceramics were obtained in sintering process at the pressure of 5.5 GPa and temperature of 1550 °C in presence of metallic Co powder. The effect of Co content (ranging from 0 wt.% to 10.0 wt.%) on the phase composition, density, microstructure, Vickers hardness and thermal conductivity of TiB2 ceramics was analyzed. A small amount of new phase Co2B has been created in the reaction of TiB2 and Co. The relative density of sintered TiB2 ceramics reached 98.1 %. When the mass fraction of Co increased, the porosity increased, while the hardness first increased and then decreased. The maximal Vickers hardness values were equal to 33.3 GPa or 28.2 GPa when the used load was of 4.9 N or 9.8 N, respectively. The highest reached value of thermal conductivity was 88.9 W˙m−1 ˙ K−1. The dense TiB2 ceramics with improved hardness and thermal conductivity were ascribed to the high pressure sintering method and Co sintering aid. High pressure sintering method provides a new way for the preparation of ceramics materials.
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高影响因子
ACS Catalysis
·
2020
·
IF 12.35
Yang Chen,Yingxin Feng,Lin Li,Jingyue Liu,Xiaoli Pan,Wei Liu,Fenfei Wei,Yitao Cui,Botao Qiao,Xiucheng Sun,Xiaoyu Li,Jian Lin,Sen Lin,Xiaodong Wang,Tao Zhang
Exclusive Pt species supported on inert substrates have not achieved satisfactory performance for cryogenic CO oxidation because of the constraint of the competitive Langmuir–Hinshelwood process in which the strongly adsorbed CO inhibits the activation of O2. Here, we develop a catalyst of Pt nanoparticles on Al2O3 that exhibits extremely high activity with 100% CO conversion at −20 °C and orders of magnitude higher specific rate than current commercial catalysts. Detailed catalyst characterizations reveal the presence of metallic Pt sites and positively charged ones associated with the OH species in Pt/Al2O3. Both experimental data and theoretical calculations suggest that CO adsorbed on Pt(OH) kink sites reacts with OH species covering Pt0 terrace sites to release CO2. Afterward, O2 is facilely activated on terrace sites to regenerate OH. The presence of OH species and the synergy between Pt kink and terrace sites on the Pt species lead to an ultralow reaction barrier for CO oxidation.
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Yuntao Xu,Yanfei Cao,Li Tan,Qiao Chen,Yuanxing Fang
Photoanodic hydrogen peroxide (H 2 O 2 ) production via water oxidation is limited by low yields and poor selectivity. Herein, four variations of cobalt phosphides, including pristine CoP and Co 2 P crystals, and two mixed-phase cobalt phosphides (CoP/Co 2 P) with different ratios, were applied as co-catalysts on the BiVO 4 (BVO) photoanode to improve H 2 O 2 production. The optimal yield and selectivity were approximately 9.6 µmol‧h −1 ‧cm −2 and 25.2 % at a voltage bias of 1.7 V vs reversible hydrogen electrode (V RHE ) under sunlight illumination, respectively. This performance is approximately 1.8 times that of pristine BVO photoanode. The roles of the Co and P sites were investigated. In particular, the Co site promotes the breaking of one H O bond in water to form OH • radicals, which is the rate-determining step in H 2 O 2 production. The P site plays an important role in the desorption of H 2 O 2 formed from the catalyst, which is responsible for the recovery of fresh catalytic sites. Among the four samples, Co 2 P exhibited the best performance for H 2 O 2 production because it had the highest rate of OH • formation owing to its improved accumulation property. This study offers a rational design strategy for co-catalysts for photoanodic H 2 O 2 production.
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PubMed
高影响因子
POLYMER SCIENCE SERIES A
·
2020
·Vol. 62
·期 6
·722-731
·
IF 0.968
Xuzhen Zhang,Lu Chen,Zhou Chenmeng,Wen Xin,Li Yong
Abstract Cellulose nanocrystals (CNC)/poly(butylene adipate- co -butylene terephthalate) composites enhanced compatibility with phthalic anhydride were one-step prepared via melt blending. The obtained composites then underwent squeezing treatment in a two-roll milling equipment at a given temperature. CNC/PBAT composites were separated and then tested via FTIR and UV–Vis spectrophotometer. During reactive blending, phthalic anhydride selectively reacts with CNC. Before squeezing, tensile strength of CNC/PBAT composites is weakened with increasing phthalic anhydride content. After squeeze treatment at an extension ratio of 6, tensile strength of CNC/PBAT (3/97) is dramatically increased from 29.6 to 148.0 MPa, which is much higher than that of pristine PBAT 85.0 MPa. SEM and WAXD results show that PBAT crystallinity is increased after orientation, and CNC show an orientation arrangement along force direction in PBAT matrix.
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高影响因子
ORGANOMETALLICS
·
2022
·
IF 3.837
Tongshun An,Chenwei Liu,Yanzhao Yin,Xiao-Feng Wu,Zhiping Yin
A general palladium and silver co-catalyzed denitrogenative carbonylation of benzotriazoles for the synthesis of benzoxazin-4-ones has been developed. Employing benzotriazoles as easily accessible substrates and Cr(CO)6 as bench-stable solid carbonyl sources, various benzoxazin-4-ones were synthesized through a ring-opening/denitrogenative/carbonylation cascade processes in moderate to good yields. Notably, this protocol avoids the use of toxic CO gas and special equipment and can also be applied to the late-stage functionalization of substrates derived from the uricosuric agent probenecid.
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高影响因子
危险品化学品经营许可证（带存储）