Journal of Cleaner Production
·
2022
·
IF 11.072
Shunan Yin,Jinxian Zhao,Shiping Wu,Xuhui Wang,Yanhong Quan,Jun Ren
Electrochemical reduction of CO 2 to valuable chemicals using electricity from renewable sources is a promising approach to realize the carbon cycle. Here, a novel bimetallic nitrogen-doped carbon catalyst (M-N-C, where M denotes the metal) CoCu–N–C electrocatalyst has been synthesized by pyrolyzing a copper-doped cobalt(II) acetate–phenanthroline complex formed from the metal acetates and 1,10-phenanthroline dissolved in ethanol. The optimal CoCu–N–C catalyst with molar ratio of Cu/(Co + Cu) = 0.15 displayed superior performance, enabling a faradaic efficiency of CO production of 76.5% at an overpotential of 0.57 V as well as an increased CO current density of 8.48 mA cm −2 at −0.98 V versus reversible hydrogen electrode (far superior than the Co–N–C of 4.20 mA cm −2 and Cu–N–C of 0.07 mA cm −2 ) and a decreased charge-transfer resistance compared with Co–N–C and Cu–N–C catalysts. The addition of Cu, which serves as a structure promoter to improve the dispersion of Co, thereby providing sufficient Co-N x active sites for the electrochemical CO 2 reduction reaction (CRR). Moreover, doping Cu changes the electronic environment around Co slightly and promotes the charge transfer capability so that reduces the energy barrier of potential-limiting energy, thereby improving the CRR performance of catalyst.
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高影响因子
Journal of Superconductivity and Novel Magnetism
·
2024
·Vol. 37
·期 8
·1475-1485
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IF 1.6
Fu Shuai,Tan Yiyu,Sun Xiaofan,Tang Zheng,Jiao Shulin,Cai H. L.,Zhang F. M.,Zhang A. M.,Wu X. S.
Here, equal numbers of La and Mn ions are successfully introduced simultaneously in SrRuO3. With increasing La/Mn doping, all compositions crystallize in Pnma with the lattice constant, together with the RuO 6 octahedral distortion, decreases. Ferromagnetism-to-spin glass magnetic behavior is observed at x ≥ 0.23. A metal–insulator transition (MIT) occurs at lower temperatures, resulting from the disordering of the metal mixture in the lattice. The retraction of the RuO 6 octahedron increases the overlap of the Ru t 2g –O 2p orbitals and broadens the Ru 4d bandwidth, leading to weaker electron–electron interactions, which may decrease the electronic and thermal conductivity.
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JOURNAL OF LUMINESCENCE
·
2019
·
IF 2.961
Olga Giraldo Giraldo,Mingzhi Fei,Rongfei Wei,Liming Teng,Zhigang Zheng,Hai Guo
Bi 3+ /Eu 3+ -doped SiO 2 –Al 2 O 3 –CaO–B 2 O 3 –La 2 O 3 –K 2 O glasses were fabricated and the luminescent properties, energy transfer as well as thermal stability were systematically investigated. Under 333 nm light excitation, bluish-green luminescence centered at 480 nm is observed in the obtained Bi 3+ -doped glass. By co-doped with Eu 3+ , highly efficient energy transfer process happens from Bi 3+ to Eu 3+ via a quadrupole-quadrupole interaction. The energy transfer efficiency can reach 86% and the concentration of Eu 3+ is not quenched in here. With increasing Eu 3+ concentration, tunable luminescence from bluish-green via white to orange-red is realized. Significantly, pure white light emission with CIE coordinates (0.348, 0.333) is obtained when excited by 333 nm light. Temperature-dependent emission spectra present superior color stability in operating temperature lower than 423 K for the prepared glasses. These results indicate that these glasses are potential white light emitting materials for organic-resin-free W-LEDs.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Xiangdong Kong,Yan Liu,Pai Li,Jingwen Ke,Zhongyu Liu,Fawad Ahmad,Wensheng Yan,Zhenyu Li,Zhigang Geng,Jie Zeng
As CO 2 coordination with the metal sites in molecular catalysts represents an effective means to CO 2 activation, it is important to develop molecular catalysts with high ability of CO 2 coordination to enhance their catalytic performance in CO 2 electroreduction. Herein, we investigated the coordinate activation of CO 2 with Co-based molecular catalysts by manipulating their ligand structures. During CO 2 electroreduction, the current density of Co-salophen for CO was −16.0 mA cm −2 at −0.75 V versus reversible hydrogen electrode ( vs RHE), which was 7.6 times of that (−2.1 mA cm −2 ) of Co-salen. In addition, the Faradaic efficiency (FE) of Co-salophen for CO reached 75 % at −0.70 V vs RHE, whereas the FE of Co-salen for CO production was 19 %. In-situ experiments and mechanistic studies revealed that both Co-salophen and Co-salen adopted a side-on coordination of CO 2 with Co sites. Moreover, the bonding between CO 2 and Co sites was strengthened in Co-salophen, resulting in the enhanced activity of Co-salophen.
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Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 35
·12037-12047
·
IF 6.4
Ruifeng Wu,Haibing Li,Yafei Liu,Aimin Chang,Bo Zhang
It is found that the linearization of the resistance–temperature curve for CaCu3Ti4O12 can be achieved by changing the energy band structure induced by Fe3+, but at the cost of decreasing temperature sensitivity. Here, a novel strategy is proposed to improve the thermal and dielectric properties of CaCu3Ti4O12 ceramics by (La,Fe)-co-doping. This can both linearize the resistance–temperature relationship by adjusting the energy band structure of the grains due to the Fe3+ doping and improve the temperature sensitivity by increasing the grain boundary potential barrier resulting from La3+ doping. The dielectric constant increases upon decreasing the grain boundary potential barrier and increasing the carrier concentration. Therefore, the dielectric constant and temperature sensitivity can be regulated by adjusting the characteristics of grains and grain boundary. This work bridges the relationship between thermal sensitivity and dielectric properties, and opens up a door for the development of a multifunctional coupler CaCu3Ti4O12 device.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Ling Liu,Yanbo Li,Man Xu,Cunwen Wang
Two-dimensional Co ultrathin metal–organic framework nanosheets (Co-UMOFNs) were synthesized and blended into poly (ether block amide) (PEBA) to prepare composite mixed matrix membranes on PVDF supports for the pervaporation of phenol aqueous solution. The membranes were characterized by XRD, ATR-IR, TGA, CA and SEM measurements. Effects of the Co-UMOFNs loading, feed temperature and feed concentration on phenol separation performance were investigated. The results showed that Co-UMOFNs have a two-dimensional layered morphology and have good compatibility with the PEBA. A “brick and mortar” architecture morphology was achieved after incorporating Co-UMOFNs into the PEBA membrane. The amorphous PE segments in the PEBA were turned into a crystalline structure, restricting the motion of PE segments. The filling of Co-UMOFNs slightly improved the thermal stability and hydrophobicity as well. With the increase of the Co-UMOFNs loading from 0% to 40%, the phenol separation factor increased from 27 to 45, and the total flux decreased from 1.2 kg m -2 h - 1 to 0.42 kg m -2 h - 1 , when separation of 1000 ppm phenol solution at 70 °C. The interlayer galleries induced by the Co-UMOFNs stacking increased the tortuosity, and the crystalline structure of the Co-UMOFNs-PEBA improved the energy barriers of water penetration. Therefore the water flux was inhibited and the phenol separation factor increased. Depression of water permeation can be another protocol to prepare high-performance organophilic pervaporation membranes.
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MACROMOLECULAR RAPID COMMUNICATIONS
·
2022
·Vol. 43
·期 21
·2200438
·
IF 5.006
Khloe Shuk-Ying Kwan,Ying-Ying Lui,Takashi Kajitani,Franco King-Chi Leung
Fabrication of macroscopic soft functional materials, such as macroscopic photoresponsive soft materials and artificial muscles, can be commonly prepared by charge screening of supramolecular assemblies with inorganic salt solutions using a shear-flow method. However, some of the charged end-groups of photoresponsive molecular amphiphiles cannot be stabilized with inorganic salt solutions to fabricate macroscopic soft materials. Stiff stilbene amphiphiles (SAs) functionalized with anionic phosphite and cationic quaternary ammonium end groups are designed and synthesized and their photochemical and supramolecular assembly properties are determined. Supramolecular co-assembly of anionic and cationic nanotubes of SAs allows to transform into nanoribbons, confirmed by transmission electron microscopy, critical aggregation concentration, and Zeta potential measurements. Nanoribbons of anionic and cationic SAs can be prepared into macroscopic soft materials with inorganic salt solutions and surprisingly also with deionized water. The macroscopic soft material of anionic and cationic SAs can be stabilized at low concentration ≈5 m m . Meanwhile, the photoresponsiveness of the macroscopic soft materials is retained to provide macroscopic morphological change upon photoirradiation. These results exhibit the feasibility in fabrication of macroscopic functional soft materials from supramolecular assembly across multiple length-scale without help of inorganic salts and offer ample opportunity in developing future soft supramolecular robotic systems.
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POLYMER BULLETIN
·
2019
·Vol. 77
·期 2
·793-804
·
IF 1.858
Gan Lu,Geng Aobo,Jin Long,Zhong Qiang,Wang Linjie,Xu Lijie,Mei Changtong
In the present study, carbon nanotubes (CNTs)–silver nanoparticles (AgNPs)-co-doped polylactic acid (PLA) nanocomposites were prepared through two-solvent-assisted method. The morphology and structure of the prepared nanocomposites were characterized, and the thermal, mechanical and antibacterial properties of the nanocomposites were tested afterward. The results indicated that the CNTs and AgNPs were well dispersed within the PLA matrix, in which the CNTs and AgNPs attached with each other. The incorporation of these two reinforcement fillers significantly enhanced the thermal stability of the PLA. Due to strong intermolecular interactions, the CNTs and AgNPs improved the tensile strength of the PLA. Additionally, the prepared nanocomposites showed promising antibacterial effect on staphylococcus haemolyticus due to the existence of AgNPs. Having improved thermal and mechanical properties, as well as antibacterial capability, the prepared PLA nanocomposites have the application potential in packaging areas.
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JOURNAL OF MATERIALS SCIENCE
·
2022
·Vol. 57
·期 44
·20580-20588
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IF 4.682
Yan Jingjing,Zhu Chengwei,Liu Baohua,Shu Ruiwen
A facile synthetic route based on the assistance of magnetic field is reported to fabricate core–shell CoB@Co(OH) 2 nanochains for purpose of the high conductive pathway and enhanced pseudocapacitance in 3 M LiOH electrolyte. By adjusting the loading amount of the shell Co(OH) 2 nanosheets anchored on the core CoB alloy surface, the typical core–shell CoB@Co(OH) 2 is endowed with the appropriate pore volume of 0.27 cm 3 g −1 and the high accessible electrode/electrolyte interfacial area (62.3 m 2 g −1 ) and the fast conductive highway; meanwhile taking advantages of core–shell structure can be favor for fast ion transport between the electrode/electrolyte interphase and rapid electron transfer. Benefiting from the advantageous properties, the typical CoB@Co(OH) 2 electrode exhibits a high specific capacitance of 492.8 F g −1 in three-electrode device together with good cyclic stability (90.4% capacitance retention) during continuously 5000 cycles at 2 A g −1 . This work can provide an inspiring strategy for rational designing of core–shell CoB@Co(OH) 2 , and indicate their potential energy application in alkaline electrolyte. Graphical abstract
Core–shell CoB@Co(OH) 2 electrode with rapid conductive highway achieves the broaden voltage of 0.8 V and the enhanced supercapacitive performance.
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JOURNAL OF SOLID STATE CHEMISTRY
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2021
·
IF 3.498
Xiaoqing Xie,Yanfei Wang,Weini Zhou,Can Chen,Zeng Xiong
A new synthetic method was designed to prepare poly (trimesoyl chloride-co-polyethyleneimine) (PEI-TMC). Characterization of PEI-TMC was investigated by FTIR, SEM, EDS , XPS, TGA , and BET. TGA test revealed that the PEI-TMC had excellent thermal stability. The BET specific surface area (4.74 m 2 g −1 ) and pore diameter of about 9.44 nm indicated that PEI-TMC possessed a mesoporous structure. The adsorption behavior of U(VI) on the PEI-TMC was investigated. The thermodynamic analysis showed that the process of PEI-TMC adsorption of U(VI) was endothermic and spontaneous, and the adsorption efficiency was better at higher temperatures. The U(VI) sorption on PEI-TMC was conformed to the Langmuir adsorption isotherm and pseudo-second-order kinetic models . The adsorption mechanism of U(VI) with PEI-TMC was systematically elucidated by XPS and FTIR. Under the best condition, the maximum adsorption capacity of PEI-TMC could reach 212.8 mg g −1 by calculating the Langmuir isothermal model. It indicated that PEI-TMC was a potential adsorbent for the treatment of U(VI)-containing wastewater.
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Cai Qi,Shu Zu,Xukun Zhu,Tong Zhang,Longyan Li,Li Song,Yachao Jin,Mingdao Zhang
Functional and active carbon material is of great concern in facilitating the performance of lithium-sulfur (Li-S) battery . In this work, we develop a bamboo-like nitrogen-doped carbon nanotubes (Co@NCNTs-2) with low cobalt metal content, which acts as not only the host matrix for sulfur loading but also an efficient catalyst for the adsorption and conversion of lithium polysulfides (LiPSs). The characterization results show that the Co particles are mainly encapsulated inside the Co@NCNTs-2, and the N species are mainly distributed on the outer surface of Co@NCNTs-2. The Co particles are the growth sites of carbon nanotubes and are wrapped by carbon to form Co@NCNTs-2. It is confirmed that the uniform graphitized structure contributes to charge transfer, while the enriched N species assist the trap and catalytic conversion of the polysulfides, thus helping to restrain the shuttle effect. As a result, the resultant Co@NCNTs-2-S cathode presents high reversible capacity at different current densities and exhibits superior cycling stability for 300 cycles at 0.5 C.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Song Lv,Liya Ma,Xinyu Shen,Hua Tong
To achieve high-performance supercapacitors, nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons (CHC-SK) are successfully prepared by one-step carbonization. In the synthesis, two effective strategies of structure design and heteroatom doping are both used to increase capacitance of carbon materials. To control and design of structure, potassium citrate as a novel pore-former is introduced into chitosan hydrogel systems. It plays three roles in pore formation and thereby can be effective to optimize structure and improve surface area of CHC-SK. In addition, thiourea as binary doping of nitrogen and sulfur can effectively maximize the pseudocapacitance of CHC-SK. Therefore, CHC-SK with large surface area (1596.4 m 2 g −1 ) and high heteroatom content (5.43% for nitrogen, 2.62% for sulfur) show excellent electrochemical performances. The specific capacitance of CHC-SK reaches up to 366.8 F g −1 at 0.5 A g −1 . Even at the high current density of 10A g −1 , its capacitance retention is 97.1% for 10,000 cycles. This simple strategy for the synthesis of nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons with high specific capacitance has promising applications in the future.
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