ENERGY & FUELS
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2020
·
IF 3.421
Hongbing Wang,Yao Xiang,Mingming Guo,Jiana Su,Gongying Wang,Wei Cui,Zhiyong Deng
Synthesis of diethyl carbonate (DEC) in the liquid phase by oxidative carbonylation of ethanol over activated carbon (AC) supported chloride-free Cu-based catalysts offers a prospective “green chemistry” strategy compared to the traditional preparation processes. The catalysts of Cu/AC were synthesized via a one-pot carbothermal method, and the Cu(+1) and Cu(0) valence distribution of Cu/AC catalyst was adjusted by simple carbon heat treatment. The physicochemical properties of the catalysts of Cu/AC were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and the Brunauer–Emmett–Teller model. The 10%-Cu/AC-873 catalyst (calcined at 873 K) exhibits the best catalytic activity for the synthesis of DEC under optimized conditions: T = 393 K, P = 4.0 MPa, PCO/PO2 = 9:1, and reaction time 2 h. The conversion of ethanol and space-time yield of DEC were 7.3% and 594.4 mg·g–1·h–1, respectively. The 10%-Cu/AC-873 catalyst was reused four times without an obvious decrease in the activity. The adsorption energies of reactive species (CO, CH3CHO, CH3CH2OCO) on Cu and Cu2O were calculated by density functional theory; the results indicate that the synergic function of Cu+ and Cu0 enhanced the catalytic performance of Cu-based catalyst.
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高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2020
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IF 6.551
Xiong Jia,Yujie He,Philippe F.-X. Corvini,Rong Ji
Humic substances are reactive during redox alteration. However, the role of this reactivity in the transformation of organic compounds and in carbon cycling in the environment is still unclear. Here, we used 14 C-radioactive tracer to study abiotic transformation and humification of catechol, a representative of naturally occurring monomeric phenols and phenolic pollutants, in suspensions of humic acids (HAs) at original and H 2 /Pd-reduced redox states with flux of air (HA org -Air and HA red -Air, respectively) or N 2 (HA org -N 2 and HA red -N 2 , respectively) for 20 min in absence and presence of Cu(II) and Fe(II). Both HA org and HA red can transform catechol in the absence of O 2 to 19% and 25% of the initially applied amount, respectively. The transformation of catechol strongly increased when air was introduced, amounting to 75% in HA red -Air treatment and 43% in HA org -Air treatment, owing to the generation of reactive oxygen species . Considerable amounts of catecholic carbons were incorporated into HAs (26% for HA red -Air and 19% for HA org -Air), constituting humification of catechol. The presence of Cu(II) strongly inhibited the overall transformation and humification of catechol, although it significantly increased humification at the start of incubation. The presence of Fe(II) overall enhanced both the transformation and humification. The results provide first insights into the impacts of redox alteration of humic substances together with the presence of metal ions with variable valences on the fate of phenolic compounds in the environment. This study points out that redox alteration-induced abiotic transformation may be one important process for dissipation of phenolic pollutants and humification of phenolic carbons in environments rich in HAs and subject to redox fluctuation.
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
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2020
·
IF 6.182
Yan Nie,Fang Wang,Hang Zhang,Donghai Wei,Siyu Zhong,Lei Wang,Guanhua Zhang,Huigao Duan,Rui Cao
In terms of solving the phase separation of metal oxides and polymer derived carbon matrix during the carbonization process, two active metal oxides with different thermal diffusion features are simultaneously introduced. The agglomeration and migration of copper-based species during the carbonization process are well suppressed by the existence of homogenous ZnO distributed in carbon matrix with less migration ability. The unique carbon-confined Cu-Zn bimetallic oxides films are constructed via a facile electrospinning method and subsequently annealing process. Taking advantage of the suppressive effect of ZnO, the agglomeration and migration of copper-based particles are restrained and thus realizes the size regulation of Cu 2 O/Cu particles as well as the confinement in carbon nanofibers. Our designed architecture not only maintains the intrinsic interface properties of carbon nanofiber, but also distinctively enhances a highly reversible lithium-ion storage nature. Moreover, the preparation technique can be applied for constructing self-supported flexible electrodes without the additional current collector, seasonably satisfying the requirement of flexible electronics industry and effectively avoiding the employment of superfluous electrode redundancy.
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RSC Advances
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2020
·Vol. 10
·期 41
·24425-24433
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IF 3.119
Shenjie Li,Tianyong Zha,Xiaoyu Gong,Qi Hu,Minghui Yu,Jinyu Wu,Ruolan Li,Jiaming Wang,Yanyan Chen
We present a facile route for the synthesis of water-soluble Cu–Cd–Zn–S/ZnS core/shell quantum dots (QDs) by simple pH regulation. The PL spectra of Cu–Cd–Zn–S/ZnS core/shell quantum dots can cover the whole visible light region in the case of only two ratios of Cu/Cd/Zn. The emission wavelength of Cu–Cd–Zn–S/ZnS QDs can be conveniently tuned from 474 to 515 and 548 to 629 nm by adjusting the pH value when the ratios of Cu/Cd/Zn are fixed at 1 : 5 : 80 and 1 : 5 : 10, respectively. It is worth noting that under the condition of a constant Cu/Cd/Zn ratio, the UV-vis absorption spectra do not change with the fluorescence spectra, indicating that the band gap of QDs remains unchanged during the change of pH value. The photoluminescence (PL) quantum yield of the as-prepared QDs with yellow emission is up to 76%. The QDs also show excellent chemical stability after the deposition of the ZnS shell. Luminescent and flexible films are fabricated by combining Cu–Cd–Zn–S QDs with polyvinyl alcohol (PVA). The QD/PVA flexible hybrid films are successfully applied on top of a conventional blue InGaN chip for remote-type warm-white LEDs. As-fabricated warm-white LEDs exhibit a higher color rendering index (CRI) of about 89.2 and a correlated color temperature (CCT) of 4308 K.
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PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2020
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IF 8.758
Duo Zhang,Alvin Dai,Binfeng Fan,Yingen Li,Kang Shen,Teng Xiao,Guangya Hou,Huazhen Cao,XinYong Tao,Yiping Tang
Li dendrites are considered as the primary cause for degradation and inevitable short circuit in lithium-metal batteries (LMBs). Although contemporary strategies have shown potential for addressing dendrite growth, none have achieved complete elimination. In this paper, a dendrite-free, three-dimensional, ordered, macro/mesoporous Cu/Zn current collector was prepared using a combination of simple colloidal crystal template and electrochemical method (electrodeposition and pulse plating). When paired with a hierarchically structured mesoporous (20–50 nm) and macroporous (450 nm) anode, this novel current collector achieved stable charge/discharge cycles of over 2000 h and a small plating/stripping potential (≈8 mV) at a current density of 0.2 mA cm–2. Coulombic efficiencies (CE) also reached 94.7% after 400 cycles. This three-dimensional, ordered, macro/mesoporous structure provides a greater specific surface area, reduces local current density, and contains a lithiophilic Zn coating that serves as preferred Li nucleation sites. By combining these factors, dendrite-free Li deposition and superior electrochemical performance improvements in LMBs have been realized.
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PubMed
高影响因子
POWDER METALLURGY
·
2020
·
IF 1.793
Dongxue Liu,Qiqi Zhang,Longchao Zhuo,Yiheng Zhang,Yanlin Wang,Jintao Xu
In this paper, a combined processing method of mechanical alloying and infiltration was used to prepare the WCu-x wt-%SiC (x = 0.5, 1, 2, 3) composites. The microstructure, density, electrical conductivity and compressive behaviour of the composites were studied comparatively. First a decreasing and then an increasing particle growth trend was obtained, indicating that a small content of SiC below 1 wt-% was beneficial for particle refinement. Besides this, with the increase of the SiC content, both the density and electrical conductivity decreased gradually. Consistent with the particle–particle contiguity of the highest value of 0.404, the WCu-1 wt-%SiC composite showed the best compressive properties. Further electron backscattering diffraction results revealed that the ultrafine-grained SiC particles, which are distributed homogeneously in the composite with lower Schmid factor values would perturb the dislocation motion to make proliferation of more dislocations, exhibiting unordinary strain-hardening during deformation.
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高影响因子
ChemCatChem
·
2020
·Vol. 12
·期 14
·3670-3678
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IF 4.853
Mengjiao Zhang,Youwei Yang,Antai Li,Dawei Yao,Yueqi Gao,Busha Assaba Fayisa,Mei-Yan Wang,Shouying Huang,Jing Lv,Yue Wang,Xinbin Ma
Graphical Cu-based catalyst : In the hydrogenation of ethylene carbonate (EC), nanoflower-like catalysts with high fiber density exhibited nearly 98 % EC conversion when the H 2 /EC ratio was decreased to 60, while the catalyst with solid sphere structure required at least a H 2 /EC ratio of 140. This is attributed to the H 2 -enrichment effect of nanoflower-like morphology with dense fibers, which accelerated the reaction rate and achieved excellent activity at a low H 2 /EC ratio. The hydrogenation of ethylene carbonate (EC) to produce methanol and ethylene glycol (EG) is one of the key steps in the promising route for CO 2 utilization on a large scale. However, the high H 2 /EC ratio in feed (usually as 200∼300) is generally required to achieve favorable catalytic activity, inducing the high cost for H 2 circulation in the industrial application. Here, we report a series of nanoflower-like catalysts with curved fibers and open ends, among which the catalyst with the highest fiber density exhibited nearly 98 % EC conversion, 75 % methanol selectivity and over 99 % EG selectivity when the H 2 /EC ratio was decreased to 60. Combining the characterizations of active species distribution and high-pressure H 2 adsorption, it is demonstrated that the nanoflower-like morphology with dense fibers could remarkably enrich the hydrogen adsorption, consequently, accelerate the reaction rate and present an excellent performance at a low H 2 /EC ratio. These insights may provide instructive suggestions for further design of catalysts for the hydrogenation reactions.
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高影响因子
Journal of Materials Chemistry A
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2020
·Vol. 8
·期 27
·13685-13693
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IF 11.301
Qianyuan Wu,Jin Wang,Zhiwei Wang,Yalan Xu,Zhihui Xing,Xinyang Zhang,Yuntao Guan,Guangfu Liao,Xinzheng Li
Here, single-atom Cu dispersed on N-doped graphene (Cu-SA/NGO) with relatively high Cu loading of 5.8 wt% was prepared for boosting the degradation of contaminants. This is the highest value yet reported for dispersion of single metal atoms on graphene. Atomically dispersed CuN4 moieties were confirmed by high-angle annular dark field-scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy. The prepared Cu-SA/NGO shows remarkable activity and stability in the degradation of various organic contaminants at neutral pH. This excellent performance is mainly ascribed to the large number of active sites obtained from high single-atom-Cu loading. Density functional theory calculations confirmed that CuN4 moieties serve as the active sites, with low energy barriers for hydroxyl radical (˙OH) generation. These supported single-atom catalysts (SACs) catalyze the heterogeneous Fenton reaction via proton-mediated H2O2-homolytic pathway. This work offers a new method for fabricating various SACs with high loading levels for catalytic oxidation reactions.
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高影响因子
Journal of the Taiwan Institute of Chemical Engineers
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2021
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IF 5.876
Shihan Wang,Siyao Bian,Jianzhuo Liu,Jihui Li,Shuying Xu,Zhenyi Liang
Background Biochar has attracted considerable attention as a low-cost adsorbent comprised of carbon matrix and mineral for treatment of wastewater. The main purpose of this work was to manufacture CaCO 3 -rich biochars using crayfish shell as feedstock for removal of Cu(II) and Pb(II) from aqueous solution. Methods Pristine and magnetic biochars were prepared via direct pyrolysis and K 2 FeO 4 -promoted pyrolysis , respectively, and characterized by element analysis, BET, FTIR, SEM-EDS, XRD and XPS. Moreover, their adsorption capabilities toward Cu(II) and Pb(II) were investigated in aqueous solution. Findings A large amount of CaCO 3 was assembled on the pristine biochar pyrolyzed at 600 °C, leading to 715.10 mg/g and 1682.87 mg/g adsorption capacities for Cu(II) and Pb(II), respectively. Whereas, CaCO 3 and single phase Fe 3 O 4 were simultaneously introduced into the magnetic biochar with K 2 FeO 4 -promoted pyrolysis at 600 °C using 1/1 (g/g) ratio of K 2 FeO 4 to crayfish shell, where 417.05 mg/g and 974.10 mg/g maximum adsorption capabilities were obtained for Cu(II) and Pb(II) with 29.66 emu/g saturation magnetism, respectively. Cu(II) and Pb(II) were mainly adsorbed onto the biochars as carbonates and oxides by their interaction with CaCO 3 and carbon matrix.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Xiao-Lu Sun,Zan Liu,Zhi-Lin Cheng
The Cu-intercalated layered h-BN/N-doped carbon-nanofiber composite films (PAN-Cu/ABN-CNFs) were successfully prepared by the combination of the electrospinning technique and the one-pot carbonization process, using the mixed solution of polyacrylonitrile (PAN) and Cu-intercalated activated boron nitride (Cu/ABN) as carbon precursor. A series of characterizations proved that the PAN-Cu/ABN-CNFs possessed the distinguished merits in the structure and composition, such as the pore feature of the micropore (0.076 cm 3 /g)-mesoporous (0.3582 cm 3 /g) structure, the structure of the exfoliated h-BN nanosheets , the low-coordination high-content N (11.65 at%) and the existence of self-reducing Cu nanoparticles (0.5 at%). For adapting the actual application, the mechanical properties of the PAN-Cu/ABN-CNFs were comprehensively evaluated, showing that the PAN-Cu/ABN-CNFs films had the robust tensile strength and bending properties as well as the desirable wear resistance. Furthermore, the selective adsorption desulphurization of the PAN-Cu/ABN-CNFs were examined by the selective adsorption removal of thiophene (TH) from the simulated oil, indicating that the optimum adsorption capacity of the fresh films was up to 78.38 mg/g in 800 mg/L initial concentration and the adsorption capacity after the four-time regeneration recycling still approached 74.894 mg/g. Finally, the adsorption kinetics , isotherm and thermodynamic studies suggested that the adsorption behavior of TH over the PAN-Cu/ABN-CNFs should be better described by the correlation coefficients of Avrami fractional-order kinetics and Liu isotherm, while the thermodynamic studies showed a favorable exothermic and spontaneous adsorption mechanism.
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高影响因子
Materials Today Communications
·
2021
·
IF 3.383
Qing Wang,Yun Mou,Jiaxin Liu,Yang Peng,Mingxiang Chen
The electrochemical behavior of additives determinates the filling process of through ceramic holes (TCHs), which is severely affected by Cu(II) concentration in the virgin make-up solution (VMS). High concentrations of Cu(II) are rarely reported in through-holes (THs) filling owing to its insufficient throwing power. High concentration CuSO 4 (0.7 M) and low concentration H 2 SO 4 (0.61 M) were confirmed as VMS, and thiazolinyl polydipropyl sulfonate (SH110), polyethylene glycol (PEG), and nitrotetrazolium blue chloride (NBT) were chosen as the accelerator, suppressor, and leveler, respectively. The electroplating performances were investigated under different plating solutions. The electrochemical behavior of additives and their combinations were evaluated by galvanostatic and cyclic voltammetric measurements. The filling performance of PEG-SH110-NBT in high Cu(II) solution is affected by convection. Plating efficiency is effectively improved by SH110 in the designed high Cu(II) plating solution. PEG and NBT have a synergistic effect on inhibition, while NBT shows a leveling effect only in the presence of SH110. The plating solution with a low air agitation flow rate effectively promotes the high-quality filling of TCHs with a high aspect ratio (AR) of 5, 4.75, and 3.8. The filled TCHs display mirror-bright surface and grain refinement without the void defects.
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高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Wei She,Jing Wang,Xuewei Li,Jingfang Li,Guijie Mao,Weizuo Li,Guangming Li
Tuning of the metal–metal/oxide interaction is a vital route to enhance the performance of the supported catalysts. In this study, a Cu/Zn bimetallic MOFs was synthesized through a simple solvothermal method by using an adenine rigid biomolecule acted as organic linker. Furthermore, a ZnO/nitrogen-doped carbon composite supported Cu catalyst (named as Cu-ZnO/NC-BMOFs) derived from the bimetallic CuZn-MOFs was obtained via one-pot pyrolysis method. The developed Cu-ZnO/NC-BMOFs catalyst was tested for hydrogenation-amination tandem reaction. The bimetallic CuZn-MOFs with the uniformly dispersed Cu and Zn centers acted as a self-sacrificing template, which could facilitate the derived catalyst with strengthened Cu-ZnO interaction, high dispersity, and more N species. All of these advantages give the developed Cu-ZnO/NC-BMOFs catalyst with higher performance in hydrogenation-amination tandem reaction compared with traditional Cu/ZnO/NC-IWI (synthesized by incipient wetness impregnation) catalyst. The Cu-ZnO/NC-BMOFs exhibits good stability for the recycling experiments with a negligible loss in its performance. More importantly, the Cu-ZnO/NC-BMOFs catalyst could convert nitroarenes into the corresponding imines or secondary amines with excellent selectivity (>90.0%). This bimetallic MOFs-derived strategy may provide a way for fabricating NC supported catalysts in other tandem reactions.
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高影响因子
危险品化学品经营许可证（带存储）