Journal of Materials Chemistry C
·
2021
·Vol. 10
·期 2
·665-671
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IF 7.393
Dandan Gao,Jiyang Xie,Jian Wang,Wanbiao Hu
It is widely accepted that localized electron hopping induces colossal permittivity in the bulk of transition-metal-based materials. However, the mechanism and the control of the electron hopping process remain to be explored. In this work, the effect of the B-site environment and multiple Cu valence-states on electron hopping were experimentally revealed in the LiCuNb2.95M0.05O9 (M = Mg, Ti) systems. The results demonstrated that Mg/Ti substitution for Nb5+ at the B-site effectively causes multivalent states of A-site Cu cations, i.e. Cu+/Cu2+/Cu3+, and distorted NbO6 octahedra. Upon Mg/Ti substitution, the dielectric permittivity was enhanced by approximately two orders of magnitude (at 1 kHz and 300 K) and an additional dielectric relaxation was induced. More importantly, it was revealed that the B-site substitution effectively adjusted the activation energy and average distances for the electron hopping.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Haitao Xu,Dianhua Song,Jiao Li,Yan Zhao,Ruijie Yang,Jingzhe Zhao
The demand for sustainable energy sources urges the development of efficient and earth-abundant electrocatalysts . Herein, chlorine assisted ion-exchange and in-situ sulfurization processes were combined to construct CuCo 2 S 4 @(Cu,Co) 2 Cl(OH) 3 heterostructures from Cu(OH) 2 nanoarrays. Chlorine element in the cobalt source stimulated the formation of (Cu,Co) 2 Cl(OH) 3 precursor, and further facilitated partial transformation of the precursor to CuCo 2 S 4 on the surface to achieve composite structure. The mixed valences of Co element (Co 3+ in CuCo 2 S 4 and Co 2+ in (Cu,Co) 2 Cl(OH) 3 ) and O S interpenetrated nanointerface in the composite catalysts provided low electron transfer resistance for good alkaline oxygen evolution reaction (OER) activities. In 1 mol L −1 KOH electrolyte, the overpotentials of the optimal composite catalyst reached 253 and 290 mV respectively at the current density of 20 and 50 mA cm −2 , which is comparable to the activity of commercial Ir/C (281 mV@20 mA cm −2 ). These findings could provide opportunities for designing effective and inexpensive composite electrocatalysts through nanointerface engineering strategy.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Yuanli Liu,Jiang Xu,Zhen Cao,Ruiqi Fu,Chuchen Zhou,Zheni Wang,Xinhua Xu
This work aimed to develop a feasible technology to reuse dead pig biowaste for heavy metals removal , which was first carbonized into pig bone char (PBC) after pyrolysis and further functionalized with amino ( NH 2 ) to improve its affinity with heavy metals. The application of PBC after NH 2 -functionalization for aqueous heavy metals removal was explored, including Pb 2+ , Cu 2+ , and different complex Cu(II) species. PBC@SiO 2 -NH 2 showed comparable performance with AC@SiO 2 -NH 2 . The adsorption capacity of Pb 2+ and Cu 2+ by PBC@SiO 2 -NH 2 was 120 and 30 mg g −1 , respectively. The NH 2 functionalization enhanced the adsorption of complex Cu(II) species, and PBC@SiO 2 -NH 2 exhibited good performance under a wide pH range and coexisting ions. The adsorption of Cu(II) EDTA species with an EDTA/Cu(II) molar ratio of 1.0 by PBC would be enhanced ~3 times and ~6 times after NH 2 functionalization and further addition of Fe 3+ , respectively. The results of EDX , elemental mapping, and XPS confirmed the adsorption of Cu(II) species. The adsorption kinetics , isotherm, and thermodynamics of different Cu(II) species by PBC@SiO 2 -NH 2 were investigated. The regeneration of PBC@SiO 2 -NH 2 was easily performed via acidic wash. These results suggested the application potential of the reuse of biowaste, which could be a promising adsorbent for aqueous heavy metals after specific functionalization.
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ENVIRONMENTAL POLLUTION
·
2016
·
IF 4.839
Dun Fu,Zheng Chen,Dong Xia,Liang Shen,Yuanpeng Wang,Qingbiao Li
Solid digestate, a by-product of anaerobic digestion systems, has led to a range of environmental issues . In the present study, a novel composite based on a solid digestate-biochar-Cu NP composite was synthesized for tetracycline removal from an aqueous medium. The removal efficiency values for tetracycline (200 mg L −1 ) were 31.5% and 97.8%, respectively, by the biochar-Cu NP composite (0.5 g L −1 ) in the absence and presence of hydrogen peroxide (H 2 O 2 , 20 mM) within 6 h of reaction time. The possible degradation pathway of tetracycline was investigated using liquid chromatography-mass spectrometry. The desorption experiment results suggested that no significant concentration of tetracycline was detected on the composite after the reaction, but a small amount of intermediates in terms of total organic carbon (TOC) accounting for 3.1%, and 23.3% of the end-product NH 4 + was adsorbed onto the biochar sheets. The dispersive Cu NPs on the biochar resulted in an increase in the surface area and pore volume of the biochar-Cu NP composite, which enhanced tetracycline adsorption as well as the degradation efficiency. Relative tetracycline removal mechanisms were dominantly ascribed to ·OH generation from the Cu(II)/Cu(I) redox reaction with H 2 O 2 and the electron-transfer process of free radicals (FRs) in biochar. The proposed approach serves dual purposes of waste digestate reuse and treatment of antibiotic pollutants. This study highlights the activation of H 2 O 2 by the dispersive Cu NPs coupling with biochar derived from a waste solid digestate for tetracycline treatment.
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JOURNAL OF RARE EARTHS
·
2020
·
IF 3.104
Di Deng,Shujun Deng,Dandan He,Zhiheng Wang,Zhipeng Chen,Yi Ji,Guoping Yan,Guangjin Hou,Licheng Liu,Hong He
Ce- or La-doped Cu/SSZ-13 catalysts were prepared by a hydrothermal method and Cu, Ce or La ions were incorporated through stepwise ion exchange. The catalyst activity was measured for the ammonia selective catalytic reduction reaction. The structure and composition of catalyst were characterized by using X-ray diffraction, scanning electron microscopy, inductively coupled plasma mass spectrometry solid-state NMR, NH 3 -TPD techniques, and the active components were examined by XPS and XANES . The results indicate that the Ce and La doping can both completely preserve the SCR activity of Cu/SSZ-13 above 300 °C, but there is also a decrease of activity below 200 °C. On the other hand, Ce doping is beneficial to the formation of framework aluminum , stabilizes molecular sieve framework and Cu active sites of Cu/SSZ-13, thereby improves the catalyst hydrothermal stability. But La doping will decrease the amount of framework aluminum and Cu active sites of Cu/SSZ-13 after hydrothermally aging, even destroy zeolite CHA structure. This is quite harmful to the catalyst hydrothermal stability.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 10
·3817-3823
·
IF 4.58
Li Jingjing,Wang Yuxian,Jiao Yunfei,Jia Ru,Chen Zhengbo
Under normal circumstances, chromate ions cannot oxidize core-shell Cu-Au nanoparticles (NPs) because the standard redox potential of the Cr(VI)/Cr(III) system is lower than that of Au(I)/Au. However, in the presence of a certain concentration of hydrogen bromide, the Nernst potential becomes higher than that of Au(I)/Au and Cu(II)/Cu (as calculated by the Nernst equation). Based on this finding, a colorimetric method was developed that is based on oxidative etching of Cu@Au NPs by chromate. The Cu-Au NPs have a light red color in the presence of 5 mM HBr. On addition of Cr(VI), the gold shell is rapidly etched from the surface of the Cu-Au NPs, and this is accompanied by a color change to blue. The color changes were characterized by UV-vis spectroscopy. The absorbance at 526 nm changes in the 0.4 nM to 1 μM chromate concentration range, and the detection limit is 0.21 nM.
Schematic of a highly sensitive and selective colorimetric method for detection of chromate based on the redox etching of Cu@Au nanoparticles induced by Cr(VI). The presence of HBr enables Cu@Au NPs to be oxidized by Cr 6+ .
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JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Yue Sun,Yingpeng Gu,Pengyu Zhang
Cu(II)-citrate (Cu(II)-CA) complex, as one of the components in plating solutions, increases the difficulty of Cu(II) treatment due to its stable structure and high mobility. In this work, a novel surface imprinted polymer (Cu-CA-SIP) for selective removal of Cu(II)-CA complex from aqueous solution is synthesized by using polyethyleneimine (PEI) grafted onto chloromethylated polystyrene (CMP) microspheres. Cu(II)-CA anions are successfully imprinted with the molar ration of 1:1 by Cu-CA-SIP at initial pH 4.0. Nearly 100% removal rate can be achieved even at low Cu(II)-CA concentration (0.5 mmol/L), and the maximum Cu(II) uptake of Cu-CA-SIP reaches 1.38 mmol/g at 303 K. In Cu(II)/Fe(III)-CA, Cu(II)/Ni(II)-CA, Cu(II)/Zn(II)-CA and Cu(II)/Cd(II)-CA systems, the relative selectivity coefficients of Cu-CA-SIP for Cu(II)-CA are 9.66, 2.32, 1.40 and 44.55, respectively. Moreover, Cu-CA-SIP can be retrieved with negligible loss of adsorption capacity after six times of reuse. The Cu-CA-SIP column can effectively treat the actual electroplating wastewater within 114 BV, and can still reach 104 BV after three dynamic cycles. Therefore, an innovative imprinted material is designed for the first time on the basis of coordination-configuration recognition mechanism for the treatment of electroplating wastewater, providing a new insight in developing surface imprinted polymer in environmental remediation.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Shengjie Xia,Xiaofeng Zhang,Xiaobo Zhou,Yue Meng,Jilong Xue,Zheming Ni
In this paper, we synthesized a series of novel layered double hydroxides (LDHs) based materials with different organic/inorganic Cu species (Cu 3 O/CuCr 1 –Cu 2 /SB–LDHs). The Cu species were distributed in the layers (defined as Cu 1 ), intercalated between the layers (Cu 2 ) and combined on the surface of the material (Cu 3 ), respectively. The percentage of each Cu specie was adjusted to reveal the connection between different modifications and their photocatalytic activities as well as the modifications and the mechanism towards the chlorophenol (2,4,6-TCP) degradation. The experimental results showed that photodegradation of TCP varied due to different Cu species, the catalyst with the highest Cu concentration between the layers had the highest TCP degradation rate of 95.1%. In addition, the apparent quantum efficiency of different Cu 3 O/Cu 1 Cr–Cu 2 /SB–LDH materials was at the range of 0.42% to 0.60%, which was higher than that of CuCr–LDHs (0.21%) and CuCr–CuSB–LDHs (0.32%). The free radical tests showed that different Cu species determined the generation of hydroxyl radical, super oxide free radical and peroxy radicals, differently. These three radicals contributed to 46.2%, 22.5% and 10.9%, respectively, for TCP degradation during the photocatalytic reaction. Therefore, it is critical to study the influence of different Cu modifications to the improvement of photocatalytic reactivity and selectivity of Cu 3 O/Cu 1 Cr–Cu 2 /SB–LDH material. In addition, the intermediates, pathway and photoreaction mechanism of TCP degradation were also investigated in detail.
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iScience
·
2022
·
IF 6.107
Tongyang Song,Yuanyuan Qi,Chen Zhao,Peng Wu,Xiaohong Li
Summary An ultrastable and efficient Cu@C/SiO 2 nanocatalyst was fabricated for the hydrogenation of ethylene carbonate, in which Cu nanoparticles are encapsulated by sorbitol-derived graphitized carbon overlayers. During the calcination of Cu-sorbitol/SiO 2 precursors under N 2 atmosphere, sorbitol decomposed to CO and CO 2 . The in situ generated CO not only reduced Cu 2+ to Cu 0 /Cu + , but also formed graphitized carbon overlayers on the Cu surface via the disproportionation of CO. The Cu@C/SiO 2 catalyst exhibited superior catalytic performance (91% MeOH yield and 43.6 h −1 TOF) at a H 2 /EC molar ratio of 20. Of particular note, the Cu@C/SiO 2 catalyst showed remarkable long-term stability during 736 h time-on-stream test without any deactivation. The graphitized carbon overlayers on the surface of Cu nanoparticles not only functioned synergistically with the surface Cu 0 /Cu + sites to promote the EC hydrogenation but also suppressed the sintering of Cu nanoparticles. Furthermore, the interaction of Cu nanoparticles and graphitized carbon overlayers stabilized the surface Cu + /(Cu 0 +Cu + ) ratio.
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Nanoscale
·
2015
·Vol. 7
·期 40
·16874-16879
·
IF 7.394
Jianyu Chen,Jun Chen,Yi Li,Weixin Zhou,Xiaomiao Feng,Qingli Huang,Jian-Guo Zheng,Ruiqing Liu,Yanwen Ma,Wei Huang
Coating nickel onto copper nanowires (Cu NWs) by one-pot synthesis is an efficient approach to improving the oxidation resistance of the nanowires. Because Ni is much less conductive than Cu, it is of great importance to understand the relationship between the thickness of the Ni coating layer and the properties of NWs. Here we demonstrate one-pot synthesis of Cu–Ni core–shell NWs with a tunable Ni thickness by simply varying the Cu and Ni mole ratio in the precursor. We have observed that an increase in Ni thickness decreases the aspect ratio, surface smoothness and network conductivity of the resulting NWs. However, Cu–Ni NWs with a thicker Ni layer display higher oxidation temperature. The optimal Cu–Ni NWs, which were prepared using a Cu2+/Ni2+ molar ratio of 1/1, have a Ni-layer thickness of about 10 nm and the onset oxidation temperature of 270 °C. The derived transparent conductive films present a transmittance of 76% and a sheet resistance of 300 Ω sq−1. The flexible heater constructed from such high quality Cu–Ni NW films demonstrates effective performance in heating and defrosting.
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Inorganic and Nano-Metal Chemistry
·
2021
·
IF 1.716
Weiqiang Xu,KaiKai Hu,Shouwen Jin,Yuting Zhang,Daqi Wang
Transition metal carboxylates with O- and N-donor ligands are interesting for their structural features. Seven novel isonicotinamide(inic)-based metal complexes of [Cd(inic)2(L1)2(H2O)2] · 2H2O (1) (L1 = 2-chloronicotinate), [Cd(inic)2(L2)2(H2O)2] (2) (L2 = 2,4-dichlorobenzoate), [Cu(inic)2(L3)2] (3) (L3 = 4-chlorophenoxyacetate), [Cu3(inic)6(L4)2(HL4)2(H2O)2] · 2H2O (4) (L4 = azelate), [Zn(inic)2(L1)2(H2O)2] · (inic) · H2O (5), [Zn(inic)(L5)(H2O)4] (6) (L5 = 3-nitrophthalate) and [Zn2(inic)2(L6)2] · 5H2O (7) (L6 = 1,4-cyclohexanedicarboxylate) have been obtained by the introduction of the carboxylates by the common solution method and are structurally featured by different techniques of EA, IR spectra, TG and SCXRD analysis. The X-ray studies told that these complexes display mononuclear to trinuclear structures with octahedral/square-pyramidal geometry around the Zn2+, trigonal bipyramidal/octahedral at the Cu2+ and octahedral for the Cd2+. The inic in 1–7 are coordinated only in monodentate fashion with its ring N, while 5 has the lattice inic. The carboxylates coordinated to the metal in monodentate, chelating bidentate and bridging bidentate fashions. The pair of complementary N-H···O H-bonds from the CONH2 of the inic were found in all compounds except 7. Except 1 and 2, all other compounds bear the CH-O contacts from the pyridine CH of the inic. The intricate intra- and intermolecular classical H-bonds, CH-N, CH-O, CH-Cl, CH2-O, O-N, O-O, Cl-O, Cl-Cl, CH-π, CH2-π, C-π, N-π, Cl-π and π-π associations are elucidated by the X-ray crystallographic studies, which push the discrete complexes into high-dimensional ordered supramolecular structures.
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ENERGY & FUELS
·
2018
·
IF 3.024
Shaobo Liu,Bo Zhang,Zhanqi Bai,Feifan Chen,Fang Xie,Jinbing Zhou,Yongkang Lu,Guangwu Miao,Jiamin Jin,Zekai Zhang
Cu2O-SiO2 composite aerogel-like adsorbents with different n(Si/Cu) were synthesized by a sol–gel method, followed by drying under atmospheric pressure, and characterized by BET, XRD, SEM, H2-TPR, XRF, and FTIR means. Their adsorption performance for thiophene and benzothiophene in model fuels was investigated with equilibrium and breakthrough adsorption experiments, respectively. The results showed that Cu2O-SiO2 composite aerogel-like adsorbents exhibited an excellent desulfurization performance based on π-complexation between Cu(I) and thiophenics. The n(Si/Cu) of Cu2O-SiO2 had an obvious effect on their physical properties and consequently desulfurization performance. The BET surface area, pore size, and pore volume decreased with the decrease of n(Si/Cu) (increase of Cu content). Only a part of Cu was incorporated into the materials. The more the Cu(I) and the higher the specific surface area, the larger the adsorption capacity was. Cu2O-SiO2-50 performed the best, and breakthrough adsorption capacities for benzothiophene and thiophene were 5.78 mg S/gads (0.90 mmol-S/mmol-Cu) and 4.76 mg S/gads (0.74 mmol-S/mmol-Cu), respectively. The adsorption data can be well fitted by both the Langmuir and Freundlich adsorption isotherms. The effect of competitive adsorption of olefins or aromatics on the desulfurization performance of adsorbents was obviously weaker compared with the result in the literature. The spent Cu2O-SiO2 adsorbents can be well regenerated by benzene–n-heptane washing. The breakthrough adsorption capacity of thiophene on the first regenerated Cu2O-SiO2-50 was 71% of that on fresh adsorbent.
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