ENERGY & FUELS
·
2022
·
IF 4.654
Chenglong Wen,Mohong Lu,Mengyang Zhao,Jie Zhu,Mingshi Li,Jian Shang,Yuhua Shan,Chunshan Song
CeO2 with three different morphologies of nanorods (CeO2-r), particles (CeO2-p), and cubes (CeO2-c) was prepared, and the guaiacol hydrodeoxygenation over their corresponding Co-based catalysts was performed at 160–220 °C, 2 MPa, a H2 flow rate of 80 mL/min, and a weight hourly space velocity of 0.7 h–1. Compared with Co/CeO2-p and Co/CeO2-c, Co/CeO2-r has smaller Co particle sizes, a higher Brunauer–Emmett–Teller surface area, and larger amount of Co active centers, oxygen vacancies, and weak acid sites. These better physicochemical properties for Co/CeO2-r provide more Co active sites for guaiacol hydrodeoxygenation, favor the adsorption and activation of guaiacol, and contribute to the cleavage of C–O. Therefore, Co/CeO2-r presents a maximum guaiacol conversion of 97.1% and the highest yield of cyclohexanol of 91.7% among these catalysts. The result shows that the shape structure of CeO2 has an important influence on the guaiacol hydrodeoxygenation performance over its corresponding catalysts.
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DOI
高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Hairong Tang,Yong He,Peixi Liu,Jiaming Shao,Fawei Lin,Zhihua Wang
Zeolitic-imidazolate framework precursors (ZIF-67) were synthesized in an inorganic solution with triethylamine as a deprotonating agent for N2O decomposition, and the catalytic activities of the pyrolysis products under different conditions were investigated. Among them, the Co/CoOx@carbon catalyst pyrolyzed at 650 °C in a N2 atmosphere (Co-650N) exhibited excellent low-temperature catalytic activity and stability, achieving 50% decomposition efficiency at 305 °C and ∼100% at 400 °C, which benefitted from its large specific surface area, great reduction performance, abundant cobalt active sites, and surface oxygen species. Further, utilizing temperature-programmed desorption (TPD) and in situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) results, it was found that N2O molecules preferentially combined with oxygen species bound to cobalt sites. The absorbed N2O was decomposed into N2 and oxygen species, and the latter was subsequently transferred to carbon frameworks. Interestingly, the amorphous graphitic carbon frameworks played an important role in transferring/storing active oxygen and regenerating cobalt sites. Moreover, Co-650N exhibited better resistance to SO2, and the efficiency could be recovered via heating and finally stabilized at 100%. Finally, the mechanisms of N2O decomposition and sulfur poisoning-reactivation on Co/CoOx@carbon catalysts were proposed for the first time.
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高影响因子
ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Lian-Kui Wu,Ji-Ming Hu
Nanoporous Co 3 O 4 (po-Co 3 O 4 ) films have been prepared on stainless steel substrate by a novel two-step method. Firstly, a composite Co 3 O 4 -SiO 2 film was fabricated via electrochemical co-deposition under a cathodic potential from the mixed sol-gel precursor. Then, the obtained composite film was underwent consecutive cycling voltammetries in a concentrated KOH solution to etch the SiO 2 component, leading to the formation of po-Co 3 O 4 films. The resultant film electrode exhibits satisfactory electrocatalytic property towards the oxygen evolution reaction (OER).
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 23
·11149-11157
·
IF 3.925
Haoran Pan,Yue Wang,Zhenjie Lu,Xinning Huang,Xingxing Chen
High-performance bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are arousing great interest aiming at efficient electrochemical splitting of water. Herein, we report a facile strategy to fabricate Co/Zn sulfide supported on Cu-foam (CoZn-S/Cu-F) as a free-standing electrode with high-performance for overall water splitting. In half-cell electrochemical systems, the overpotentials required to reach the current densities of ±10 mA cm−2 for the OER and HER are only 170 and 130 mV, respectively. After a long-term stability test running 20 000 cyclic voltammograms, the respective potential losses for the OER and HER are only 82 and 41 mV at ±50 mA cm−2. The constructed overall water splitting system driven by simulated solar energy also exhibits prominent performance with gas bubbles continuously generated at both electrodes. A cell voltage of only 1.58 V is required to reach the current densities of ±10 mA cm−2, surpassing the commercialized noble metal and state-of-the-art non-noble metal electrodes. The excellent performance for the overall water splitting is ascribed to the CoS nanoparticles covered with ZnS nanoflocs on the highly conductive Cu-foam, which allows close interfacial contact with the electrolyte, promotes mass and charge transfer, and facilitates desorption of the generated gas from the catalyst surface.
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高影响因子
CHEMISTRY LETTERS
·
2022
·Vol. 51
·期 4
·395-398
·
IF 1.715
Zhu Yue,Li Yue,Zhao Shipeng,Jing Ran,Zhang Heqian,Sun Daolai,Sato Satoshi
Hydrogenation of γ-valerolactone (GVL) to form 1,4-pentanediol (1,4-PDO) was performed over Co/ZrO2 catalysts with a Co metal loading of 15 wt. %. The calcination of Co/ZrO2 at high temperatures significantly promoted the catalytic activity irrespective of the decrease in the specific surface area. The 750 °C-calcined Co/ZrO2 with Co2+ species exhibited a high catalytic performance: a GVL conversion of 86.1% with a 1,4-PDO selectivity of 97.2% was achieved at 165 °C under 5 MPa H2 pressure.
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高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2015
·
IF 4.721
Guangwei Rong,Jincheng Mao,Hong Yan,Yang Zheng,Guoqi Zhang
A new approach to the selective synthesis of (E)-vinyl sulfones has been developed via a Fe/Cu co-catalyzed sulfonylation of arylpropiolic acid or phenylacetylene with sulfonyl hydrazides. A variety of vinyl sulfones have been obtained in moderate to good yields, comparable to the best results reported so far. The inexpensive Fe/Cu co-catalyzed method features a simple experimental procedure and good tolerance of substrate.
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DOI
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2020
·
IF 4.006
Chenglin Cao,Yuyuan Wang,Shaoming Zheng,Jie Zhang,Wei Li,Baobi Li,Ruijie Guo,Jun Yu
Poly (butylene adipate- co -terephthalate) (PBAT)/titanium dioxide (TiO 2 )/silver (Ag) composite biofilms were prepared via a common solvent casting method and then used for food packaging. The effects of TiO 2 /Ag nanoparticles on the physical, antibacterial, and antiseptic properties of the composite biofilms were comprehensively investigated. Results showed that the physical properties, such as mechanical, UV blocking, and barrier properties, of PBAT matrix were remarkably improved by the incorporation of TiO 2 /Ag nanoparticles . The optimum performance was achieved when the concentration of TiO 2 /Ag nanoparticles was 5% (w/w). Given the excellent antibacterial activity of TiO 2 /Ag nanoparticles, the composite biofilms exhibited unique antibacterial performance against Escherichia coli and Staphylococcus aureus . In addition, the results of the cherry tomato preservation experiment indicated that the composite biofilms possessed good food preservation ability, which ensures that the present composite biofilms can be utilized in the food packaging industry.
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高影响因子
Journal of Physical Chemistry C
·
2017
·
IF 4.536
Qiang Wu,Haifeng Zhao,Fei Huang,Juan Hou,Haibin Cao,Zhiyong Liu,Shanglong Peng,Guozhong Cao
The introduction of various amounts of reduced graphene oxide (RGO) to CdS/CdSe quantum dots co-sensitized solar cells was investigated to enhance the light absorption and to promote the electron transfer. The characterization and comparison of optical and electrochemical properties as well as the performance of the resultant quantum dot-sensitized solar cells (QDSCs) with different amounts of RGO have been investigated systematically. The introduction of RGO demonstrated to enhance the light harvesting and consequently increase the short-circuit current density (Jsc). ZnS inserting between QDs and RGO can effectively block the charge recombination at the interface; however, the defects of RGO in the TiO2/QDs/ZnS/RGO photoanode still may accelerate the interface charge recombination in QDSCs and lead to a slight decrease of the open-circuit voltage (Voc). The balance between the light harvesting and charge recombination in RGO modified QDSCs is a key for achieving high power conversion efficiency (PCE). Finally, the CdS/CdSe/ZnS co-sensitized cell with modification RGO (3 min) achieved a high PCE of 5.28% (Jsc = 15.8 mA/cm2, Voc = 572 mV), more than 13% higher than that of 4.69% (Jsc = 13.7 mA/cm2, Voc = 602 mV) obtained for the cell without RGO.
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高影响因子
Nano Energy
·
2018
·
IF 13.12
Li An,Jianrui Feng,Yu Zhang,Yong-Qing Zhao,Rui Si,Gui-Chang Wang,Fangyi Cheng,Pinxian Xi,Shouheng Sun
Transition-metal nitrides (TMNs), especially iron-based TMNs, have high electrical conductivity , superior chemical stability and unique oxygen-reaction ability, and have emerged as a new form of noble metal-free electrocatalysts . In this paper, we demonstrate that the ORR-active/OER-inert single function catalyst Fe-N can be made as the OER/ORR-active bifunctional catalyst Co-Fe-N by controlled substitution of Fe with Co. To obtain atomic insights of the Co-enhanced OER catalysis, we develop a new exfoliation method to prepare atomically thin (1.1 nm) nanosheets (NSs) of Co x Fe 1-x N 0.5 (x = 0, 0.05, 0.1, 0.15 and 0.2). Our studies show that both electronic structure and local binding environment of Fe are modified by Co substitution and the Co-Fe-N NSs show a volcano−like OER catalysis with Co 0.15 Fe 0.85 N 0.5 NSs being the most efficient OER catalyst, showing the lowest overpotential of 266 mV at 10 mA cm −2 , a Tafel slope of ∼30 mV dec −1 , and excellent stability in the 1.0 M KOH OER condition. Density functional theory (DFT) calculations suggest that the Co-Fe sites in the Co 0.15 Fe 0.85 N 0.5 structure are optimized to promote OH* to O* conversion, O*-O* coupling and O 2 formation. The Co 0.15 Fe 0.85 N 0.5 NSs are a class of new noble-metal-free catalyst for OER.
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高影响因子
Frontiers in Energy
·
2023
·Vol. 18
·期 1
·110-121
·
IF 2.9
Ge Yang,Shen Quanhao,Zhang Qi,Li Naixu,Lu Danchen,Zhang Zhaoming,Fu Zhiwei,Zhou Jiancheng
Metal-free graphitic carbon nitride (g-C 3 N 4 ) has captured significant attention as a low-cost and efficient hydrogen production photocatalyst through. Effectively regulating the microstructure and accelerating the separation of photogenerated carriers remain crucial strategies for promoting the photocatalytic performance of this material. Herein, a novel sulfur–carbon co-doped g-C 3 N 4 (SCCN) hierarchical microtubules filled with abundant nanosheets inside by thermal polymerization is reported. Numerous nanosheets create abundant pores and cavities inside the SCCN microtubes, thereby increasing the specific surface area of g-C 3 N 4 and providing sufficient reactant attachment sites. Besides, the hierarchical structure of SCCN microtubules strengthens the reflection and scattering of light, and the utilization of visible light is favorably affected. More importantly, co-doping S and C has greatly improved the photocatalytic performance of graphitic carbon nitride, optimized the band gap structure and enhanced the photogenerated carrier splitting. Consequently, the SCCN exhibits a remarkable photocatalytic H 2 evolution rate of 4868 µmol/(g·h). This work demonstrates the potential of multi-nonmetal doped g-C 3 N 4 as the ideal photocatalyst for H 2 evolution.
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DOI
高影响因子
ACS Applied Energy Materials
·
2018
·
IF 0
De-Yin Wang,Peng-Cheng Ma,Jia-Chi Zhang,Yu-Hua Wang
Samples of Er3+–Yb3+ co-doped Y7O6F9 are synthesized by solid state reaction method, and their down- and up-conversion luminescence are studied. Upon excitation into the 4F7/2 level of Er3+ at 490 nm, effective energy transfer from Er3+ to Yb3+ via cross-relaxation Er3+ (4S3/2) + Yb3+ (2F7/2) → Er3+ (4I13/2) + Yb3+ (2F5/2) occurs, splitting an absorbed high-energy photon (λ = 490 nm) into two photons (λ = 1000 and 1540 nm). Based on the changing of the lifetime of Er3+4S3/2 → 4I15/2 emission without and with Yb3+, the efficiency of Er3+ → Yb3+ energy transfer in Y7O6F9:1%Er3+,9%Yb3+ has been evaluated to 58%. Upon excitation at 980 nm, as the Yb3+ doping concentration increases, not only an overall increase in intensity but also an enhancement of the red (4F9/2 → 4I15/2) emission with respect to the green (4S3/2 → 4I15/2) emission were observed. Under 980 nm laser excitation with power of 20 mW, the overall integrated emission intensity in the 500–700 nm of Y7O6F9:1%Er3+,5%Yb3+ is 1.8 times higher than that of β-NaYF4:2%Er3+,18%Yb3+ that is to date the most efficient up-conversion phosphor. In view of the efficient down-/up-conversion in Er3+-Yb3+ co-doped Y7O6F9, this material is expected to be used to enhance the efficiency of solar cells.
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DOI
CARBOHYDRATE POLYMERS
·
2015
·
IF 4.074
Jifei Cui,John F. Kennedy,Jun Nie,Guiping Ma
Amines monomers, N , N -dimethylaminoethyl methacrylate (DMAEMA), N , N -dimethylethanolamine (DMEA), 2-dimethylaminoethylamine (DMEDA) and N -methiyldiethanolamine (MDEA) were used to induce the formation of calcium carbonate (CaCO 3 ) crystals on chitosan films, by using (NH4) 2 CO 3 diffusion method at ambient temperature. The obtained CaCO 3 particles were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The influence of reaction variables, such as the additive concentration and their types were also investigated on the products. The morphologies of CaCO 3 crystals, inter-grown in cube-shape, were controlled by DMAEMA and DMEA. It was observed that the morphologies of CaCO 3 changed from the cube grown arms to massive calcite with a hole on the face by increasing the concentrations of DMEDA and MDEA. While the precipitation grew on chitosan film without any organic additive, only single cube-shaped crystals were obtained. By these results the possible mechanisms can be proposed that electronic movement of the groups on the monomer effected ions configuration and molecules absorbed on the exposed surface, resulted the change of the surface energy, which caused the change in the morphology of CaCO 3 .
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高影响因子
危险品化学品经营许可证（带存储）