APPLIED SURFACE SCIENCE
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2020
·
IF 6.182
Mengmeng Yang,Liwei Jin,Mingyi He,Zao Yi,Tao Duan,Weitang Yao
Low silicon oxide (SiO) is a promising anode material for lithium and potassium ion batteries due to its high theoretical capacity (~2400 mAh g −1 ) and good cycle performance. However, volume effects and poor intrinsic electronic conductivity during cycling limit its practical application. To meet this challenge, we synthesized SiO x @C (SC) anodes with various carbon contents by ball milling and high-temperature carbonization. The graphite/asphalt coating reduces the volume expansion of SiO and reduces the mechanical stress. When used as a lithium ion battery (LIB) electrode, the SC-2 material retained a lithium storage capacity of 729.5 mAh g −1 after 200 cycles at a current density of 200 mA g −1 . In addition, when used as a potassium ion battery (KIB) electrode, the SC-2 material provides a high capacity with a discharge capacity of 107.0 mAh g −1 after 400 cycles at 200 mAh g −1 and excellent cycle life (after 2000 cycles at 500 mA g −1 , the capacity 80.8 mAh g −1 was retained). The potassium storage mechanism of the SC electrode was analyzed by the simple ex-situ XRD technique. These results show that SC anodes are promising for application as anode materials for LIBs and KIBs.
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高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
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2020
·
IF 6.444
Xueai Li,Wenqi Dong,Can Zhang,Wanchun Guo,Chunsheng Wang,Yingmei Li,Haiyan Wang
Two-dimensional microwave-absorbing materials (MAMs) with abundant preferable interfaces are highly desirable for high-performance microwave absorption. Herein, a leaf-like Fe/C structure, consisting of iron veins interpenetrated in amorphous carbon lamina, was fabricated by reducing a petal-like iron alkoxide in an H 2 /Ar atmosphere. The synthesized leaf-like Fe/C composites dissipate microwaves in an effectively similar process green to leaves absorbing sunlight. First, the unique leaf-like structure enables microwaves to pass into the composites because the 2D amorphous carbon, with its high BET surface area, provide adequate access for microwaves. Then, the incident microwave is attenuated by the distinctly improved dielectric loss caused by enhanced interface polarization and an effective magnetic loss from the natural resonance of iron. Therefore, the leaf- like Fe/C composite shows microwave absorption with a maximum reflection loss of − 59.7 dB, whose effective bandwidth (reflection loss ≤ − 10 dB) covers the whole Ku band and X band with thicknesses of only 1.5 mm and 2.0 mm, respectively.
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高影响因子
FUEL PROCESSING TECHNOLOGY
·
2020
·
IF 4.982
Xin Gou,Francis Okejiri,Zihao Zhang,Miaomiao Liu,Jixing Liu,Hao Chen,Kequan Chen,Xiuyang Lu,Pingkai Ouyang,Jie Fu
Integration of aqueous-phase reforming of methanol (APRM) into the production of value-added fatty alcohols via hydrogenation of fatty acids is an attractive and efficient process in biomass conversion . Herein, we present tannin-derived carbon-supported monometallic Cu/C, Co/C and bimetallic Cu-Co/C catalysts with different Cu/Co ratios for in situ hydrogenation of lauric acid in a methanol-water hydrothermal system. The catalysts were made by a simple mixture of tannin and the metal salts, followed by pyrolysis in an H 2 atmosphere. Through synergism induced by Cu-Co interactions, the bimetallic Cu-Co/C catalyst with Cu/Co ratio of 1:4 (CuCo 4 /C) exhibits higher catalytic activity than monometallic Cu/C catalyst towards lauric acid conversion, as well as higher selectivity to lauryl alcohol than monometallic Co/C catalyst. The CuCo 4 /C catalyst is composed of metallic Cu, metallic Co, and amorphous carbon , characterized by high surface area (194.5 m 2 /g) and hierarchical structure. The obtained lauryl alcohol yield in the methanol-water hydrothermal system is significantly higher than other alcohol-water systems, namely ethanol, 1-propanol, and isopropanol hydrothermal systems, highlighting its higher generation rate of hydrogen. Also, the effects of process parameters including the quantity of methanol, catalyst loading and reaction time on the conversion of lauric acid were systematically studied and optimized.
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高影响因子
Nanoscale
·
2020
·Vol. 12
·期 7
·4374-4382
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IF 6.895
Xingmei Guo,Cheng Qian,Xiaohan Wan,Wei Zhang,Haowei Zhu,Junhao Zhang,Hongxun Yang,Shengling Lin,Qinghong Kong,Tongxiang Fan
Streptococcus thermophilus, a Gram-positive (G+) bacterium featuring a teichoic acid-rich cell wall, has been employed as both a phosphorus source and template to synthesize a biomorphic Co2P-Co3O4/rGO/C composite as an efficient electrocatalyst for the oxygen reduction reaction (ORR). Different from the conventional method for the synthesis of phosphides, bio-derivative phosphorus vapor was emitted from the inside out, which facilitated the in situ transformation of the chemically adsorbed Co precursor on the bacteria into Co2P-Co3O4 heterogeneous nanoparticles, which featured a Co2P-rich body and Co3O4-rich surface. Besides, reduced graphene oxide (rGO) was also introduced in the synthetic process to keep Co2P-Co3O4 scattered and further promote the electron transport efficiency. All the Co2P-Co3O4 nanoparticles and rGO sheets were supported on the bacteria-derived carbon substrate with submicron-spherical morphology. The as-obtained Co2P-Co3O4/rGO/C composite exhibited excellent electrocatalytic performance for ORR with onset and half-wave potentials of 0.91 and 0.80 V vs. RHE, respectively. Furthermore, its long-term stability and methanol tolerance were better than those of commercial Pt/C. Thus, this work presents a new strategy of using an interior bio-phosphorus source to obtain heterojunction particles featuring a phosphide-rich body and oxide-rich surface, which may provide some insights for the construction of efficient heterogeneous electrocatalysts.
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PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
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IF 7.489
Tan Dang,Guiqing Zhang,Qinggang Li,Zuoying Cao,Guanhua Zhang,Huigao Duan
Nanohybrid-type Ni-Co-phosphide/C (Ni-Co-P/C) hollow microflowers with ultrathin nanosheets (HUNs) are constructed through a modified ethylene glycol-mediated self-assembly process and further phosphating treatment. The peculiar structure can availably provide affluent mass transfer channels and active sites, meanwhile inhibit the aggregation of nanosheets. The synergistic effects of the produced Ni-Co-P/C are demonstrated systematically through regulating the initial Ni/Co ratio. A remarkable specific capacity of 205 mAh g −1 can be achieved at 1 A g −1 , and the optimized Ni 1 -Co 2 -P/C (referred to as NiCoP/CoP/C) still holds a superior rate capability with a capacity retention of 71% even at 50 A g −1 . Notably, the electrode also reveals an attractive capacity of 133 mAh g −1 with a high mass loading of 9.1 mg cm −2 . A hybrid supercapacitor assembled with Ni 1 -Co 2 -P/C cathode and N -doped porous carbon anode demonstrates outstanding electrochemical performance, such as a high energy density (43 Wh kg −1 at a power density of 818 W kg −1 ) and excellent stability (90% retention after 20,000 cycles at 12 A g −1 ). The facile fabrication process and attractive performance make Ni 1 -Co 2 -P/C HUNs promising in energy storage applications.
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PubMed
高影响因子
MATERIALS & DESIGN
·
2020
·
IF 6.289
Qianqian Zhao,Guo Feng,Feng Jiang,Shanfang Lan,Junhua Chen,Feifei Zhong,Zuzhi Huang,Hui Pan,Jianmin Liu,Qing Hu,Weihui Jiang
A novel recoverable visible-light photocatalyst, amorphous Fe 2 TiO 5 /C composite, was prepared via nonhydrolytic sol-gel method with carbon-containing precursors as in-situ carbon sources. It is demonstrated that the precursors, iron ethoxide and butyl titanate, react to form Fe-O-Ti bonds in gel through a ether elimination reaction and amorphous Fe 2 TiO 5 at 300 °C, which finally crystallizes at 600 °C. The residual organic groups form uniform-doped C. Interestingly, the photocatalytic activity of amorphous Fe 2 TiO 5 /C is distinctly superior to those of its crystalline counterparts without C and P25 (43-fold increase and 12-fold increase, respectively), which is mainly attributed to the incorporation of C (8.17 wt%) and amorphous Fe 2 TiO 5 with a hollow spherical structure and a high BET surface area of 195.5 m 2 /g. Importantly, the photocatalyst can be recovered with a recovery rate of 100% simply by an external magnetic field, making it have promising applications in the wastewater treatment field.
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高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Zhaohuan Wei,Yaqi Ren,Hong Zhao,Minkang Wang,Hui Tang
Alkaline fuel cells are considered as promising energy conversion devices for future application, and oxygen reduction reaction (ORR) catalyst is one of the critical factors in determining fuel cells' performance. However, the application of conventional Pt-based catalysts is limited by its high cost and insufficient reserve. Here we synthesized TiC/C nanofibers as ORR catalyst through electrospinning. The morphology, TiC content, and interface between TiC and carbon in TiC/C nanofibers could be adjusted by changing preparation conditions. The changes in material properties affect the catalytic performance due to the synergistic enhanced effect between TiC and carbon. The best TiC/C sample (TCNFs/C) exhibited the ORR performance with the onset potential, peak potential, peak current density, and charge transfer number of 0.941 V vs. RHE, 0.812 V vs. RHE, 0.742 mA cm −2 , and 3.29, respectively, as well as good catalytic durability and excellent methanol tolerance. The results demonstrate the great research value and application potential of TiC/C nanofibers as ORR catalysts.
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高影响因子
NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 44
·期 15
·5792-5799
·
IF 3.288
Xilong Wang,Chen Yang,Lijuan Cao,Han-Pu Liang
Alloying Pt with less expensive 3d-transition metals is effective for increasing the electrocatalytic activity and CO tolerance while decreasing Pt consumption. Herein, well-dispersed and highly alloyed Pt–Co bimetallic nanoparticles supported on commercial carbon black have been synthesized by means of a facile one-pot solvothermal approach without using any bulky capping agents. The best performing Pt1.2Co/C, with an average particle size of 4.7 ± 0.8 nm, has a large electrochemically active surface area of 64.30 m2 g−1, which is comparable to that of 66.73 m2 g−1 of commercial Pt/C and larger than that of other synthesized catalysts. The as-synthesized Pt1.2Co/C shows about 3 times enhanced mass activity and specific activity for methanol oxidation reaction compared to commercial Pt/C (20 wt%). Meanwhile, the electrocatalytic performance of Pt1.2Co/C for hydrogen evolution reaction (HER) in acid media is also superior to commercial Pt/C and the overpotential is only 33.8 mV when the current density reaches 70 mA cm−2. This work demonstrates that the developed strategy provides a facile platform for the synthesis of high-performance, low-cost and robust catalysts in practical catalysis, and energy storage and conversion.
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高影响因子
CARBON
·
2020
·
IF 8.821
Yang Fei,Mei Liang,Tao Zhou,Yang Chen,Huawei Zou
Recently, lightweight and highly efficient electromagnetic interference (EMI) shielding composites are crucial but changing for the development of modern electronics and telecommunication. Here, a novel polyhedral Co/C particle embedded carbon nanofiber (CNF@Co/C) aerogels were synthesized via pyrolysis of bacterial cellulose wired zeolitic imidazolate frameworks-67 (ZIF-67) aerogel under argon. The flexible CNF@Co/C aerogels exhibit a high EMI shielding effectiveness (SE) is approaching 56.07 dB at a density of only 0.023 g cm −3 in the X band , and the average absorption coefficient is as high as 0.79, indicating 79% of electromagnetic (EM) waves are absorbed in shielding process. The remarkable performance results from the three-dimensional (3D) CNF-threaded porous structure with interconnected network and the magnetic Co/C particle strung by CNF, which contribute to a conduction loss and optimal impedance matching along with multiple polarization and strong magnetic loss. This work paves a promising way for the new generation of electronic device with lightweight and efficient EMI shielding.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 26
·12103-12113
·
IF 3.553
Jin Tianxiang,Chen Jianfa,Wang Chunyan,Qian Yong,Lu Limin
A three-dimensional (3D) fluorine-doped graphene aerogel (FGA) with rich semi-ionic C–F bonds was synthesized via a facile hydrothermal method and applied as the electrode material in supercapacitor. A porous 3D network structure with a high specific surface area of the FGA has been confirmed by the combination of scanning electron microscopy, transmission electron microscopy and N 2 adsorption method. X-ray photoelectron spectroscopy spectra indicated that the FGA was doped predominantly with semi-ionic C–F bonds, which ensured the high electronic conductivity and sufficient electrochemistry active sites of FGA. As a result, the FGA electrode showed a high specific capacity of 279.8 F g −1 at a current density of 0.5 A g −1 , which is much better than that of undoped graphene aerogel (UGA, 141.6 F g −1 ). Even though the current density increased to 10 A g −1 , 90.6% of its specific capacitance was retained. The FGA also maintained about 94.3% of the initial capacitance after 5000 cycles at a current density of 0.5 A g −1 . Furthermore, the assembled FGA//FGA symmetric supercapacitor presented a high energy density of 26.2 W h kg −1 at a power density of 899 W kg −1 . Accordingly, this work offers a facile and efficient approach to produce fluorine-doped graphene materials for high-performance supercapacitor applications.
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高影响因子
ChemElectroChem
·
2021
·Vol. 8
·期 18
·3512-3518
·
IF 4.59
Hong-Ji Li,Jing-Jing Li,Zhe Chen,Zhen-Zhen Wang,Jin Qu,Yi-Qian Chen,Li-Jun Zhu,Fei Jiang
Graphical Blocky road : Sodium dual-ion batteries (SDIBs) with Sb/C/G anode and expanded graphite (EG) as cathode, NaClO 4 as salts can deliver superior electrochemical performance, for example, a high discharge capacity of 376 mA h g −1 with a higher ICE (69.1 %) at current density of 500 mA g −1 , a excellent cycling stability (73 mA h g −1 is retained even after 1400 cycles at current density of 1000 mA g −1 ), and high stable CE of 99.0 %. Sodium ion-based dual ion batteries (SDIBs) have attracted increasing attentions for their high operative voltages and low cost, but their poor long-term cycling stability and rate capability largely hinder their practical applications. Here, an optimized anode-antimony/carbon/graphene (Sb/C/G) composite for SDIBs is designed. Sb nanoparticles (NPs) not only can enhance the specific capacity but also facilitate the Na + diffusion kinetics. The continuous conductive carbon matrix can promote the electron transfer process and accommodate volume changes of Sb NPs during sodiation/desodiation. Therefore, superior electrochemical performance, for example, a high discharge capacity of 376 mA h g −1 with a higher ICE (69.1 %) at current density of 500 mA g −1 , an excellent cycling stability (73 mA h g −1 is retained even after 1400 cycles at current density of 1000 mA g −1 ), and high stable CE of 99.0 %. Our study offers a suitable design for Na + -based batteries anode structure and accelerates their practical applications.
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高影响因子
Energies
·
2021
·Vol. 14
·期 15
·4520
·
IF 3.004
Xiaokang Yang,Jiaqi Sun,Guang Jiang,Shucheng Sun,Zhigang Shao,Hongmei Yu,Fangwei Duan,Yingxuan Yang
Membrane water content is of vital importance to the freezing durability of proton exchange membrane fuel cells (PEMFCs). Excessive water freezing could cause irreversible degradation to the cell components and deteriorate the cell performance and lifetime. However, there are few studies on the critical membrane water content, a threshold beyond which freezing damage occurs, for cold storage of PEMFCs. In this work, we first proposed a method for measuring membrane water content using membrane resistance extracted from measured high frequency resistance (HFR) based on the finding that the non-membrane resistance part of the measured HFR is constant within the range of membrane water content of 2.98 to 14.0. Then, freeze/thaw cycles were performed from −50 °C to 30 °C with well controlled membrane water content. After 30 cycles, cells with a membrane water content of 8.2 and 7.7 exhibited no performance degradation, while those higher than 8.2 showed significant performance decay. Electrochemical tests revealed that electrochemical surface area (ECSA) reduction and charge transfer resistance increase are the main reasons for the degradation. These results indicate that the critical membrane water content for successful cold storage at −50 °C is 8.2.Keywords:freezing durability;cold start;membrane water content;performance degradation;proton exchange membrane fuel cell
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高影响因子
危险品化学品经营许可证（带存储）