Nanoscale
·
2017
·Vol. 9
·期 17
·5467-5474
·
IF 7.367
Yue Sun,Yunjie Zhou,Cheng Zhu,Lulu Hu,Mumei Han,Aoqi Wang,Hui Huang,Yang Liu,Zhenhui Kang
Highly efficient electrocatalysts remain huge challenges in direct methanol fuel cells (DMFCs). Here, a Pt–Co3O4–CDs/C composite was fabricated as an anode electrocatalyst with low Pt content (12 wt%) by using carbon dots (CDs) and Co3O4 nanoparticles as building blocks. The Pt–Co3O4–CDs/C composite catalyst shows a significantly enhanced electrocatalytic activity (1393.3 mA mg−1 Pt), durability (over 4000 s) and CO-poisoning tolerance. The superior catalytic activity should be attributed to the synergistic effect of CDs, Pt and Co3O4. Furthermore, the Pt–Co3O4–CDs/C catalyst was integrated into a single cell, which exhibits a maximum power density of 45.6 mW cm−2, 1.7 times the cell based on the commercial 20 wt% Pt/C catalyst.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
Advanced Powder Materials
·
2023
·
IF 0
Cheng Li,Yatian Deng,Liping Yang,Bo Liu,Dong Yan,Liyuan Fan,Jian Li,Lichao Jia
Sr 2 FeCo 0.2 Ni 0.2 Mo 0.6 O 6-δ (SFCNM) and Sr 2 FeNi 0.4 Mo 0.6 O 6-δ (SFNM) were prepared as the hydrogen electrode materials for solid oxide cells (SOCs) and comparatively investigated by density function theory (DFT) and experiments to demonstrate the benefit of Co addition. The reduced SFCNM (R-SFCNM) and SFNM (R-SFNM) contain exsolved Fe–Co–Ni and Fe–Ni nanoparticles, respectively. DFT indicates that Fe–Co–Ni has optimized combination of the d-band center (descriptor of catalyst activity) and adsorption behavior for H 2 O, H 2 , H, and OH. The cell with SFCNM hydrogen electrode, La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ (LSGM) electrolyte, and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) oxygen electrode (Cell-SFCNM) demonstrates a higher performance than that with an SFNM hydrogen electrode (Cell-SFNM) at temperatures between 700 and 850 °C in both solid oxide fuel cell (SOFC, 3% H 2 O-97% H 2 /air) and solid oxide electrolysis cell (SOEC, 20% H 2 O-80% H 2 /air) modes. At 850 and 700 °C, the peak power density is 1.23 and 0.48 W·cm −2 in SOFC mode, while the current density is 1.25 and 0.37 A·cm −2 at 1.3 V in SOEC mode, respectively. The performance degradation rates at 750 °C are 0.17 mV·h −1 in SOFC and 0.15 mV·h −1 in SOEC modes within 150 h, which are improved by Co doping.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
FUEL
·
2023
·
IF 7.4
Jie Yu,Zhuoran Hou,Huayu Zhang,Xinsheng Zhou
The fabrication of electrode materials with a high specific capacitance is essential for the development of enhanced performance supercapacitors. A novel binder-free electrode material, composed of MnS/Ni 3 S 2 and Co(OH) 2 , was synthesized on nickel foam by hydrothermal, sulfuration, and electrodeposition techniques. The MnS/Ni 3 S 2 exhibited a unique flower-like structure, resulting in a high specific capacitance of 1780 F g −1 at 1 A/g. By optimizing the synthesis conditions through several characterization and electrochemical tests, the MnS/Ni 3 S 2 @Co(OH) 2 composite was obtained, which displayed an ultrahigh specific capacitance of 2495 F g −1 at 1 A/g and a capacitance retention rate of 86.1% after 5000 cycles at 10 A/g in three-electrode system. The synergistic coupling of MnS/Ni 3 S 2 and Co(OH) 2 , along with the conductive nickel foam substrate, donated towards the excellent electrochemical performance. Furthermore, the MnS/Ni 3 S 2 @Co(OH) 2 //AC asymmetric supercapacitor (ASC) device was constructed with MnS/Ni 3 S 2 @Co(OH) 2 as positive electrode, activated carbon (AC) as negative electrode and 1 M KOH solution as electrolyte, demonstrated a high energy density of 68.6 Wh kg −1 at 750 W kg −1 and excellent cycle stability with 91.2% capacitance retention after 10,000 cycles at 15 A/g. The outstanding electrochemical properties observed in both the pre-electrodeposition and post-electrodeposition samples indicate the effectiveness of reasonable design and construction of composite as a pathway for producing electrode materials with exceptional performance.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2023
·Vol. 26
·期 4
·557-565
·
IF 3.1
Jiaqiang Ding,Bingyu Xiao,Jinqiu Wu,Dongliang Chen,Dongling Huang,Zuochun Xiong
Poly(ε-caprolactone-co-trimethylene carbonate) (PCLTMC) is a biodegradable copolymer, which is widely used for medicine and tissue repair systems, and its morphology, degradation and mechanical properties have been extensively investigated. However, its crystallization behavior with different copolymerization ratios has not been studied systematically, which is of great significance for the study of property regulation and an understanding of the crystallization behavior of random copolymers. In this paper, the relationship between the crystallization temperature Tc, melting point temperature Tm and crystallinity Xc of copolymers with different molar ratios was determined by differential scanning calorimetry (DSC) using a non-isothermal crystallization method. The results show that the melting point and crystallinity of the copolymer decrease with an increase in TMC composition. The equilibrium melting point of the copolymers was predicted by an isothermal crystallization method, using the Hoffman–Weeks extrapolation method and crystallization rate growth fitting method both based on Lauritzen–Hoffman theory. It is proved that Lauritzen–Hoffman theory is of great significance for guiding the kinetic behavior of PCLTMC crystallization.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Junmei Luo,Shufeng Bo,Qingda An,Zuoyi Xiao,Haisong Wang,Weijie Cai,Shangru Zhai,Zhongcheng Li
Rational design of ordered catalytic composites with high performance and facile preparation method for environmental remediation still remains a tremendous challenge. For this vision, ordered composites with confined cobalt intercalated N/C layers (Co–N/C) were successfully prepared via carbonizing a mixture of cobalt species, histidine (His) and zirconium-containing SBA-15 (ZS) utilizing a simple non-solvent method. Taking the confinement effect and inherent hydrophilic groups (Si–OH) of mesoporous silica as the foothold, the strong Co 2+ /N or Co 2+ /O coordination (Co 2+ (–COO - or –NH 2 ) 2 and Co 2+ (–O - ) 2 ) and silica/His or His/His adhesive/cohesive interactions endowed the Co-based catalyst with optimal interfacial properties , cycling stability and magnetic separability for degradation of several pollutants (phenol, antibiotics and dyes). The degradation efficiency of Co@NC-ZS-700 for bisphenol A was superior to Co-ZS-700, NC-ZS-700 and Co@NC-SBA-700 due to the flaky structure with confined Co–N/C layers, which could achieve 95.0% within 20 min. In addition, the catalyst could still degrade more than 84.4% bisphenol A after five consecutive reactions. Based on the characterization analysis, tested active species (SO 4 •– , • OH and 1 O 2 ) and degradation products, double-process activation mechanism and degradation pathways were plausibly proposed (radical and non-radical processes). Additionally, various influencing factors, including carbonization temperature, amount of cobalt species, peroxymonosulfate (PMS)/catalyst dosage, pH value, coexisting ions and real water environment, were also systematically studied. This work might pave a feasible way for contaminant treatment utilizing ordered mesoporous silica composites with diffusion promoted channels involved under aqueous systems.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2018
·Vol. 148
·期 8
·2348-2358
·
IF 2.911
Lin Jin,Guo Yafei,Li Changhai,Lu Shouxiang,Chen Xiao,Liew Kim Meow
A series of supported and bulk Cu–Mn–Ce ternary oxide catalysts was synthesized by wet-impregnation (IM), deposition–precipitation (DP), traditional co-precipitation (CP), co-precipitation with cetyltrimethyl ammonium bromide (CC), and sol–gel (SG) methods. The supported catalysts (CuMn/Ce-IM, CuMn/Ce-DP) exhibited significantly higher activity for CO oxidation than the bulk catalysts (CuMnCe-CP, CuMnCe-CC and CuMnCe-SG). The improved performance could be attributed to the presence of more isolated CuO and MnO x entities on the surface of supported catalysts, which contributed to the efficient utilization of both lattice oxygen from CeO 2 and spillover oxygen from surface MnO x . For bulk catalysts, major Cu–Mn species were doped to form \({\text{C}}{{\text{u}}_{\text{x}}}{\text{M}}{{\text{n}}_{\text{y}}}{\text{C}}{{\text{e}}_{1 - {\text{x}} - {\text{y}}}}{{\text{O}}_{2 - {\text{z}}}}\) solid solutions and a part of them were coated by ceria mechanically. Lowest 50% CO conversion temperature were achieved at 76.9 °C for CuMn/Ce-IM catalyst. Low-temperature CO oxidation activities of all catalysts were in the sequence of CuMn/Ce-IM > CuMn/Ce-DP > CuMnCe-SG > CuMnCe-CC > CuMnCe-CP. Graphical Abstract
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2011
·
IF 3.463
Jing Wang,Zongbao Wang,Jun Li,Bingjie Wang,Ji Liu,Peng Chen,Menghe Miao,Qun Gu
Chemically modified chitin nanocrystals were synthesized by grafting poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) onto chitin backbone via chlorination. Acetyl amino group was maintained in the reaction. The chemical structure and morphology of PHBV grafted chitin nanocrystals were characterized by Fourier transform infrared, Transmission electron microscopy and X-ray photoelectron spectroscopy. Contact angle measurement showed that the lipophilicity of chitin was improved by the surface modification. The effects of original chitin and PHBV-graft-chitin nanocrystals on the crystallizing and melting behavior of PHBV were studied by differential scanning calorimeter (DSC). The results indicated that both unmodified and modified chitin nanocrystals suppressed crystallization of PHBV. The melt point of PHBV was increased after being mixed with nanofillers.
研究领域:
材料科学
·
生物化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Runjiang Guo,Weixing Huo,Kaifeng Wang,Dongliang Shi,Jiadong Wu,Hua Li,Hezhou Liu
In this report, we synthesized novel Co–Zn co-doped stannate (Co x Zn 1-x SnO 3 ) hollow balls via an ion co-precipitation method. The as synthesized Co x Zn 1-x SnO 3 exhibited excellent dielectric and magnetic properties , which were conducive to the microwave absorption. We also embedded the as prepared Co x Zn 1-x SnO 3 nanoparticles into rGO 3D aerogels (rGO@Co x Zn 1-x SnO 3 ) to enhance their microwave absorbability. Several characterization techniques were utilized to investigate the structures, morphologies, compositions and specific surface areas of the Co x Zn 1-x SnO 3 and rGO@Co x Zn 1-x SnO 3 aerogels respectively. In addition, associated electromagnetic parameters of various as prepared samples were also measured to simulate the microwave absorbability of the 3D rGO@Co x Zn 1-x SnO 3 aerogels. The simulation results indicated that the maximum reflection loss (RL max ) of rGO@Co 0.7 Zn 0.3 SnO 3 could reach up to −38 dB at 10.6 GHz with an absorber thickness of only 3 mm. The maximum efficient absorption bandwidth (EAB) of the rGO@Co 0.7 Zn 0.3 SnO 3 hollow balls was over 8 GHz (from 10 GHz to 18 GHz) with an absorber thickness of only 3.5 mm. The enhanced performance was ascribed to high attenuation capability, reasonable impedance matching, multiple interfacial polarizations and proper synergistic effect. This work demonstrated that the rGO@Co x Zn 1-x SnO 3 aerogels with light-weight and strong microwave absorbability have great potential to be used as a microwave absorber.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2020
·
IF 7.888
Jie Zhang,Chuang Li,Weixiang Guan,Xiaozhen Chen,Xiao Chen,Chi-Wing Tsang,Changhai Liang
Co(Ni)/MoO 3 catalysts were prepared, characterized and evaluated for the hydrogenolysis of bio-derived dibenzofuran (DBF), aiming at the understanding of the promoting effect of Co/Ni on MoO 3 for high-yield production of aromatic products. All Co(Ni)/MoO 3 catalysts selectively cleaved C-O bond, thus effectively transformed DBF to biphenyl (BP) at relatively moderate conditions. The experimental results from varying Mo species by adjusting the reduction temperature of MoO 3 together with XPS and in-situ XRD characteristic were evident that Mo 5+ species was responsible as the major active specie for the reaction. Promotional effect between Co(Ni) and Mo in Co(Ni)/MoO 3 catalysts was observed, resulted from the presence of acidic Co(Ni)MoO 4 species and a large number of Mo 5+ species both of which were created local to the Co(Ni)-O-Mo interface, as can be characterized by in-situ XRD, XPS, H 2 -TPR, NH 3 -TPD, in-situ FT-IR, Raman and TEM. The trend of the initial reaction rate follows: MoO 3 (0.18 μmol∙g cat −1 ∙s −1 ) < Ni/MoO 3 (0.26 μmol∙g cat −1 ∙s −1 ) < Co/MoO 3 (0.29 μmol∙g cat −1 ∙s −1 ), corresponding to the decreasing activation barrier. And the best catalytic activity was observed for the 100% yield of BP over Co/MoO 3 . A possible mechanism, including Co(Ni) facilitated reduction of Mo 6+ to Mo 5+ and Co(Ni) enhanced formation of acidic sites, is proposed to be responsible for the high activity in Co(Ni)/MoO 3 catalysts.
研究领域:
催化化学
·
可再生能源
·
材料科学
✓ 已验证
DOI
高影响因子
HELVETICA CHIMICA ACTA
·
2022
·Vol. 105
·期 6
·e202200017
·
IF 2.201
Geng-Wei Liu,Peng-Bin Pan,Xin Zhang,Yuan-Yuan Huang,Peng Liu,Ye-Yan Qin,Yuan-Gen Yao
Zinc titanate (ZnTiO 3 ) has recently been applied in various areas for its unique properties. Herein, through tuning the phase structures of ZnTiO 3 support, we synthesized two different Pd-based catalysts for CO oxidative coupling to DMO and further investigated their structure-activity relationships for the first time. The results indicated that the strong metal-support interaction between the cubic phase ZnTiO 3 and Pd species leads to an enriched Pd electronic density and promotes the bridged CO adsorption. As a result, the as-synthesized catalyst with cubic phase ZnTiO 3 performed a turnover frequency (TOF) of 339.3 min −1 , which was much higher than the hexagonal one (226.3 min −1 ).
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
IONICS
·
2024
·Vol. 30
·期 3
·1723-1733
·
IF 2.4
Zhao Ji-wei,Wei Zhi-qiang,Wang Can,Zhou Mei-pan,Lu Cheng-gong
The Co-based organic skeleton was combined with graphene oxide (GO) as a precursor, Ni 2+ hydrolysis etching was introduced, and finally, NiCo-LDH/GO was obtained. The final composite electrode material NiCo 2 S 4 /rGO was obtained by high-temperature vulcanization. The introduction of MOFs and rGO significantly increased the specific surface area of the material and made it have excellent electrochemical properties. The specific capacitance of the composite NiCo 2 S 4 /20rGO reaches an astonishing 272.5 mAh g −1 when the current density is 1 A g −1 . In addition, at a large current of 10 A g −1 , the specific capacitance of the material can also reach 139.5 mAh g −1 , and after a long cycle of 5000 cycles at such a current density, the capacity remains at the original 73.2%. With NiCo 2 S 4 /20rGO electrode material as the positive electrode and activated carbon as the negative electrode, the hybrid supercapacitor is assembled. At an energy density of 56.9 Wh kg −1 , its power density reaches an excellent 799 W kg −1 , and it still has a capacity retention rate of 74% at a current density of 10 A g −1 . The excellent properties of composites demonstrated in this work open up new possibilities for high-quality energy storage devices.
研究领域:
材料科学
·
电化学
·
储能
·
纳米技术
·
无机化学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Jingshan Hou,Jie Shi,Langping Dong,Jianghua Wu,Ganghua Zhang,Haijie Chen,Wei Gao,Yongzheng Fang
The discovery of pure-red emitting phosphor is great meaningful for the achievement of high color rendering index white light emitting diodes , but still a challenge due to the strict crystal field limitations. In this work, we demonstrate the preparation of a 630 nm pure-red emitting Ca 3 Si 2 O 7 :Eu 2+ phosphor for the first time through a CO reduction strategy. The changes in crystal field strength caused by different methods for the preparation of Ca 3 Si 2 O 7 :Eu 2+ are investigated and discussed based on the understanding of the thermodynamic theory and structure resolution. Finally, a white light-emitting diode with a high color rendering index (Ra = 98) is accomplished by combining the as-prepared Ca 3 Si 2 O 7 :Eu 2+ pure-red emitting phosphor with a 375 nm chip and the commercial used blue and green phosphors. The results also demonstrate the generalizability of the weak reduction strategy for the exploration of “redder” Eu 2+ doped phosphors.
研究领域:
材料科学
·
光电子学
·
固态物理
·
无机化学
·
照明技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）