APPLIED CATALYSIS A-GENERAL
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2020
·
IF 5.006
Wanliang Yang,Meng Chen,Jiayuan Zhou,Yingnan Duan,Yinmin An,Mao Liu,Mengkui Tian
Porous carriers play an important role in the catalytic transformation of syngas into higher alcohols, which promises higher sustainability in C1 chemistry. In this work, a series of hierarchical hollow silica spheres (HHSS) supported Cu-Fe bimetal catalysts were successfully prepared through ultrasonic-assisted impregnation for higher alcohols synthesis from syngas. Structural characterization results indicate that the hierarchical hollow structure of HHSS support can be maintained and the Cu-Fe bimetallic nanoparticles are highly dispersed on HHSS surface. The catalytic performances of samples in the test of CO hydrogenation for higher alcohols synthesis were investigated. The results revealed that the conversion rate of CO and the selectivity of C 2+ OH alcohol increased first and then decreased with the decrease of the amount of Cu content in the Cu x Fe y @HHSS catalyst. The highest CO conversion, alcohol selectivity and STY ROH over Cu-Fe@HHSS catalyst are 65.1 %, 46.6 %, and 118.1 gkg −1 h −1 , respectively. It was found that a large number of CuFe 2 O 4 were formed in Cu-Fe@HHSS catalyst and also confirmed that the CuFe 2 O 4 spinel and CuO-CuFe 2 O 4 were converted to Cu-Fe 5 C 2 composite in the spent Cu-Fe@HHSS catalyst, which can enhance the synergy between Cu-Fe bimetals. Furthermore, copper and iron are highly dispersed on HHSS after the reaction, which enhances the structural stability of the catalyst. Based on the development and utilization of low-cost catalysts and the production of clean liquid fuels, HHSS has a great prospect of catalyst support in the energy field.
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高影响因子
ANALYTICAL BIOCHEMISTRY
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2020
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IF 2.877
Lijun Wang,Tianyu Liao,Hong Zhou,Yukun Huang,Pengfei Chen,Xiao Yang,Xianggui Chen
Development of a rapid and sensitive method for Salmonella spp. detection is of great importance for ensuring food product safety due to its low infective dose. In this study, a colorimetric method based on the peroxidase-like activity of Cu(II)-modified reduced graphene oxide nanoparticles (Cu 2+ -rGO NPs) and PCR was successfully developed to detect Salmonella spp. in milk. Under optimal conditions, the developed colorimetric method exhibited high sensitivity and strong specificity for Salmonella spp . detection. The limit of detection was 0.51 CFU/mL with a linear range from 1.93 × 10 1 to 1.93 × 10 5 CFU/mL. A specificity study demonstrated that this method can specifically distinguish Salmonella typhimurium and Salmonella enteritidis from other foodborne pathogens. The application of the proposed method for milk sample detection was also validated, and the recovery rates of S . typhimurium in spiked milk sample ranged from 102.84% to 112.25%. This colorimetric sensor exhibits enormous potential for highly sensitive detection of bacteria in milk sample.
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PubMed
高影响因子
ACS Catalysis
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2020
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IF 12.35
Zihao Zhang,Meizan Jing,Hao Chen,Francis Okejiri,Jixing Liu,Yan Leng,Haolan Liu,Weiyu Song,Zhaoyin Hou,Xiuyang Lu,Jie Fu,Jian Liu
The catalytic transformation of renewable fatty acids into value-added fatty alcohols without the use of gaseous hydrogen is a versatile technique for the utilization of microalgae and waste cooking oil, where Cu-based catalysts are considered to be the most suitable candidate. However, the interpretation of the structure–reactivity relationship caused by different crystal types of carriers and the metal–support interface is not well understood. Herein we synthesized ZrO2-supported Cu nanoparticle catalysts via different preparation methods and reduction temperatures under similarly exposed surface facets and Cu valency but different polymorphic phases of ZrO2 (monoclinic ZrO2: m-ZrO2; tetragonal ZrO2: t-ZrO2) and the metal–support interface. Interestingly, the as-synthesized Cu/t-ZrO2 catalysts showed remarkably better catalytic performance than Cu/m-ZrO2 for the in situ hydrogenation of lauric acid in the methanol–water system. Combined experimental and density functional theory (DFT) calculation results ascribed the lower efficiency of m-ZrO2 as a carrier to weakly adsorbed reactant and intermediate molecules as well as the absence of an oxygen vacancy in the crystal phase. The interface-rich Cu/t-ZrO2 catalysts displayed higher activity normalized to the surface-exposed Cu sites toward lauryl alcohol production than the interface-deficient counterparts. DFT calculation results further revealed that this metal–support interface plays an important role in promoting the C–O bond or H–H bond cleavage in two possible reaction routes, thus reducing the activation barrier of the overall reaction.
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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
·
2020
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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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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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POWDER METALLURGY
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2020
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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
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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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
ACS Applied Materials & Interfaces
·
2020
·
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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高影响因子
ENERGY & FUELS
·
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
POWDER TECHNOLOGY
·
2020
·
IF 4.142
Jian-Rong Li,Feng-Kang Wang,Chi He,Cenyan Huang,Hang Xiao
A series of carbon-supported Cu Co oxide catalysts (Cu-Co/C) were prepared via the combination methods of impregnation and pyrolysis using Co-doped Cu-based metal organic framework (Cu 3 (BTC) 2 ·3H 2 O, Cu-BTC) precursor. Physicochemical properties of prepared catalysts were characterized by using various technologies and toluene was chosen as the probe molecule to evaluate their catalytic performance. Results revealed that the successive calcination in Ar and air was conducive to the formation of 3D porous carbon matrix and homogeneous elemental dispersion. The Cu-Co/C catalysts with spinel structure exhibited higher catalytic activity than that of Cu-500/C material. Moreover, CuCo 0.5 /C material exhibited superior catalytic durability and water resistance in catalytic oxidation of toluene. The excellent catalytic performance of CuCo 0.5 /C was mainly related to large specific surface area, high amounts of surface chemisorbed active oxygen and high ratio of Co 2+ /Co 3+ .
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