MICROCHIMICA ACTA
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2019
·Vol. 186
·期 7
·1-8
·
IF 5.479
Cao Yu,Wang Luona,Wang Chengyin,Su Dawei,Liu Yunling,Hu Xiaoya
A photoelectrochemical (PEC) sensor was constructed for the detection of non-electroactive malathion. It is based on the use of a hierarchical CuO material derived from a Cu-BTC metal-organic framework (where BTC stands for benzene-1,3,5-tricarboxylic acid). The modified CuO was obtained by calcination of Cu-BTC at a high temperature (300 °C) and possesses a high photocurrent conversion efficiency. Under irradiation with visible light and in the presence of malathion, the formation of the CuO-malathion complex on the CuO gave rise to an increase in steric hindrance. This results in a decrease in photocurrent. This novel PEC detection method has a lower detection limit of 8.6 × 10 −11 mol L −1 and a wide linear range (1.0 × 10 −10 ~ 1.0 × 10 −5 mol L −1 ).
Schematic presentation of the Cu-BTC MOF derived photoelectrochemical sensor for non-electroactive malathion detection.
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PubMed
高影响因子
CELLULOSE
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2019
·Vol. 26
·期 8
·5051-5063
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IF 3.917
Wang Xue,Jiang Shengjun,Cui Sheng,Tang Yinhan,Pei Zifan,Duan Haoran
Abstract The pore structure of the regenerated cellulose hydrogel was used as a microreactor for generating magnetic MnFe 2 O 4 nanoparticles via in situ co-precipitation technology. Sodium periodate and sodium chlorite were used as oxidants, and the carboxyl modification of magnetic cellulose aerogels was achieved through a two-step oxidation reaction. The method used was convenient and environmental-friendly, and the raw materials were also green and non-toxic. The addition of magnetic nanoparticles promoted the adsorption and enabled the recycling of materials. The results showed that the adsorption equilibrium time was only 120 min and adsorption capacity could be increased by increasing the adsorption temperature. The maximum adsorption capacity of Cu(II) was 73.70 mg/g at 25 °C when the initial concentration of solution was150 mg/L. The adsorption behaviour towards Cu(II) followed the pseudo-secondary reaction kinetics and the Langmuir isotherm adsorption model. According to the results of XPS, carboxyl and hydroxyl groups were the main active adsorption sites for Cu(II). Moreover, all the composite aerogels exhibited good reusability and could be easily separated from the water after adsorption. Graphical abstract The pore structure of the regenerated cellulose hydrogel was used as a microreactor for generating magnetic MnFe 2 O 4 nanoparticles via in situ co-precipitation technology. Sodium periodate and sodium chlorite were used as oxidants, and the carboxyl modification of magnetic cellulose aerogels was achieved through a two-step oxidation reaction. According to the results of XPS, carboxyl and hydroxyl groups were the main adsorption sites for Cu(II). Moreover, all the composite aerogels exhibited good reusability and could be easily separated from the water after adsorption.
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Journal of Materials Chemistry A
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2019
·Vol. 7
·期 10
·5453-5462
·
IF 10.733
Yanling Qiu,Hexiang Zhong,Wenbin Xu,Taotao Zhang,Xianfeng Li,Huamin Zhang
The conversion of CO2 into value-added chemicals by employing renewable energy via an electrochemical process has received increasing attention. However, the low reaction rate and efficiency, as well as poor selectivity, have limited its further development. The low solubility of CO2 in an aqueous solution is one of the main factors that limit the reaction rate and selectivity of the electroreduction of CO2 (ERC) at a high overpotential. In this study, an organic additive containing an –NH2 group (methyl carbamate, MC) was incorporated into the ERC electrolyte for the first time. By utilizing the affinity interaction between a Lewis acid (the –NH3+ group formed by protonation of the –NH2 group) and a Lewis base (CO2), the ERC reaction rate was increased by 17%, and the faradaic efficiency for the production of CH4 reached 81.6%, which represented a large increase of 34% and surpassed that of most reported Cu electrodes. Furthermore, the partial current density for the production of CH4 was 31 mA cm−2 at −2.13 V (vs. RHE), which represents an increase of 30% in comparison with that in the blank system. In addition, the competitive hydrogen evolution reaction was substantially inhibited, and the decline in faradaic efficiency increased from 38.5% to 48.1% when the potential decreased gradually from −1.63 V to −1.98 V (vs. RHE). DFT calculations further indicate that the –NH3+ group can significantly promote the adsorption of CO* and CHO* on the Cu surface and increase the surface coverage of both intermediates. CHO* can be further stabilized by the –NH3+ group via the facilitation of partial electron transfer from Cu to C and the formation of H-bonds, which is favorable for further hydrogenation to form hydrocarbons. These results provide a simple and powerful way to increase the reaction rate and product selectivity of the reduction of CO2.
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高影响因子
CHEMISTRY OF MATERIALS
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2018
·
IF 9.89
Yecan Pi,Jun Guo,Qi Shao,Xiaoqing Huang
The design of efficient Ir-based catalyst for oxygen evolution reaction (OER) in acidic conditions is the key for realizing the commercialization of polymer electrolyte membrane technology. This study reports a class of highly porous Ir–Cu nanocrystals (P-IrCux NCs) through a facile chemical dealloying strategy. Featuring the increased active surface area and plenty of defects, the newly generated P-IrCux NCs are highly active and stable toward OER in acidic conditions. The optimized P-IrCu1.4 NCs exhibit the current density of 12.8 mA cm–2 at the potential of 1.55 V (vs RHE), presenting 3.5-fold improvement in mass activity and 1.8-fold improvement in specific activity over the pristine solid IrCu1.4 NCs (S-IrCu1.4 NCs). Moreover, the obtained P-IrCu1.4 NCs also show excellent OER stability with negligible potential shift after continuous electrolysis in 0.05 M H2SO4 for 10 h. Further analysis reveals that the coordinatively unsaturated atoms at defects result in the higher oxidation state of iridium, which promotes the optimized intrinsic activity of P-IrCux NCs. This work highlights a promising strategy to create three-dimensional porous Ir-based catalysts for enhancing OER electrocatalysis.
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Advanced Energy Materials
·
2019
·Vol. 9
·期 27
·1901396
·
IF 24.884
Hao Yang,Yu-wen Hu,Jun-jie Chen,M.-Sadeeq (Jie Tang) Balogun,Ping-ping Fang,Shanqing Zhang,Jian Chen,Yexiang Tong
The challenge in the artificial CO 2 reduction to fuel is achieving high selective electrocatalysts. Here, a highly selective Cu 2 O/CuO heterostructure electrocatalyst is developed for CO 2 electroreduction. The Cu 2 O/CuO nanowires modified by Ni nanoparticles exhibit superior catalytic performance with high faradic efficiency (95% for CO). Theoretical and experimental analyses show that the hybridization of Cu 2 O/CuO nanowires and Ni nanoparticles can not only adjust the d-band center of electrocatalysts to enhance the intrinsic catalytic activity but also improve the adsorption of COOH* intermediates and suppress the hydrogen evolution reaction to promote the CO conversion efficiency during CO 2 reduction reaction. An in situ Raman spectroscopic study further confirms the existence of COOH* species and the engineering intermediates adsorption. This work offers new insights for facile designing of nonprecious transition metal compound heterostructure for CO 2 reduction reaction through adjusting the reaction pathway.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 37
·21232-21243
·
IF 10.733
Lechen Diao,Tao Yang,Biao Chen,Biao Zhang,Naiqin Zhao,Chunsheng Shi,Enzuo Liu,Liying Ma,Chunnian He
Developing highly efficient and low-cost bifunctional electrocatalysts towards the oxygen reduction reaction (ORR) is important for Zn–air batteries (ZABs) but still a challenge. In this work, electronic reconfiguration and structural optimization are simultaneously conducted to enhance the oxygen reduction reaction (ORR) electrocatalytic activity of Co2P nanoparticles, which were doped with Cu and confined within 2D ultrathin N,P-codoped carbon (NPC) nanosheets. Density functional theory calculations reveal that Cu doping can lead to more positive sites at the neighbouring Co site and weaken the binding force between the surface active sites and the adsorbed intermediates, while the 2D ultrathin nanosheets with Cu doped Co2P nanoparticles tightly anchored can remarkably boost the surface exposure of actives sites endowing such an architecture with efficient mass and charge transport pathways. As expected, the optimized Cu doped Co2P on 2D ultrathin N,P-codoped carbon (Cu-Co2P@2D-NPC) with 7.1% Cu doping exhibits a higher half-wave potential of 0.835 V than Pt/C (0.830 V). Meanwhile, flexible solid state ZABs assembled based on the 7.1%Cu-Co2P@2D-NPC hybrid deliver a high power density of 52.5 mW cm−2 and 32 h stability in the flat and folded states. This promising work holds significant potential to fabricate an efficient electrocatalyst for flexible solid state ZABs and further understand the relationship between the structure and activity.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2018
·Vol. 29
·期 17
·14971-14980
·
IF 2.324
Zhu Jianjun,Ma Lirong,Feng Jin,Geng Tianli,Wei Wei,Xie Jimin
In this paper, the X% Cu–ZrO 2 (X = 0, 1, 5, 10, 15 and 20) xerogel catalysts have been successfully synthesized via a facile two-step approach involving epoxide-driven sol–gel method followed by chemical reduction. The series xerogel catalysts were characterized using XRD, SEM–EDS, TEM, XPS, H 2 -TPR, N 2 adsorption–desorption and FT-IR. The results showed that the morphologies of ZrO 2 partly have changed from bulk to nanorods with the increase in Cu loading from 0 to 20%. The catalysts exerted Cu content-dependent activities towards the catalytic hydrolysis of ammonia borane (AB). Among them, the 15% Cu–ZrO 2 showed the best catalytic activity that the maximum hydrogen generation rate was 0.384 mol min −1 . The hydrolysis reaction towards AB was proved to the first order by the 15% Cu–ZrO 2 xerogel by kinetic studies. The activation energy was calculated to be 22.34 kJ mol −1 . Even after five recycle experiment, the catalysts also showed a good recycle stability in aqueous solution.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2018
·
IF 4.229
Cong Wang,Hongli Wang,Zhili Wang,Xiaoju Li,Yue Chi,Minggang Wang,Dawei Gao,Zhankui Zhao
Ammonia borane (AB) has been identified as one of the most promising candidates for chemical hydrogen storage . However, the practical application of AB for hydrogen production is hindered by the need of efficient and inexpensive catalysts. For the first time, we report that the incorporation of Mo into Cu@Co core-shell structure can significantly improve the catalytic efficiency of hydrogen generation from the hydrolysis of AB. The Cu 0.81 @Mo 0.09 Co 0.10 core-shell catalyst displays high catalytic activity towards the hydrolysis dehydrogenation of AB with a turnover frequency (TOF) value of 49.6 molH 2 mol cat −1 min −1 , which is higher than most of Cu-based catalysts ever reported, and even comparable to those of noble-metal based catalysts. The excellent catalytic performance is attributed to the multi-elements co-deposition effect and electrons transfer effect of Cu, Mo and Co in the tri-metallic core-shell NPs.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2018
·
IF 3.779
Liang Liu,Rui Bao,Jianhong Yi,Dong Fang
Mono-dispersed and homogeneous carbon nanotube (CNT)/copper (Cu) composite powders were fabricated by spraying pyrolysis (SP) method successfully. Subsequently, CNT/Cu composites were obtained by spark plasma sintering (SPS) at sintering temperature ranged from 1023 to 1223 K (70–90% melting point of pure Cu). The mechanical properties , micro-morphology and interface microstructure of CNT/Cu composites were measured and characterized. The results reveal that Cu nano-particles (NPs) coated on the CNT surface are conducive to improving the wettability of CNT within matrix and reducing the interface energy between matrix and CNT, and finally stable interface structure is established. The traditional trade-off tendency between strength and ductility is balanced in the CNT/Cu composites, which are sintered at 1223 K. The ultimate tensile strength (UTS) shows 344 MPa and the elongation is 19.6%, which owing to the improvement of CNT–Cu interface bonding. At last, the role of interfacial bonding extent played in determining the load transfer efficiency of CNT is discussed.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2018
·
IF 5.667
Shiyu Xu,Xuejiao Dong,Siqi Chen,Yangyang Zhao,Guiye Shan,Yingchun Sun,Yanwei Chen,Yichun Liu
Creating high-index facet gold nanorods (Au NRs) is important for catalytic application. The high-index facet exhibits tremendously catalytic activity comparing with low-index facet. Herein, Cu 2+ ions were chosen to induce Au NRs to form high-index {200} facet. Firstly, Au/Cu NRs with high-index facets induce high-density charge distribution at local position, which led to the surface enhanced Raman scattering enhancement. Furthermore, the active electrons transfer from Au/Cu NRs to H 2 O 2 make them show peroxidase-like properties. The catalytic activity of Au/Cu NRs was confirmed by the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB) by H 2 O 2 . According to Michaelis-Menten equation, the catalytic activity of Au/Cu was higher than Au NRs by 4.5 times. Meanwhile, the oxTMB molecules may be deoxidized to TMB molecules by the antioxidant of ascorbic acids. On the basis of this phenomenon, the colorimetric determination of ascorbic acid in real samples (vitamin drink) was developed with a detection limit of 25 μM.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Xingyu Guo,Xiangqing Li,Lixia Qin,Shi-Zhao Kang,Guodong Li
Development of photocatalysts with high activity and durability for hydrogen generation is extremely desired but still remains a great challenge currently. With Cu nanoparticles (Cu NPs) as a linker between TiO 2 microsphere (TiO 2 MS) and 5, 10, 15, 20- meso -tetra(4-carboxyphenyl)porphyrin (TCPP), a novel nano-micro hybrid (TiO 2 MS-Cu-TCPP) was prepared via a facile method. By bridging TiO 2 MS and TCPP with Cu NPs, the absorption and the electron transfer of TiO 2 MS were greatly improved. When the TiO 2 MS-Cu-TCPP was employed as the photocatalyst for hydrogen evolution, it exhibited higher activity and stability than those of the TiO 2 MS, the TiO 2 MS-Cu and the TiO 2 MS-TCPP, TiO 2 MS-Cu-CuTCPP and TiO 2 MS-TCPP-Cu. The photocatalytic activity was enhanced for about 6 times with respect to that of the pristine TiO 2 MS. The excellent performance for the nano-micro hybrid can be attributed to wide light absorption, more reactive sites, and facilitated interfacial electron transfer owing to the strong interaction between TiO 2 and TCPP with Cu NPs as the linker and cocatalyst. Subsequently, a high and stable photocatalytic activity over the TiO 2 MS-Cu-TCPP nano-micro hybrid was achieved, demonstrating the importance of interfacial modification to a semiconductor photocatalyst. This result gives us a new perspective of constructing special structures for efficient light utilization and electron transfer.
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高影响因子
Catalysis Science & Technology
·
2018
·Vol. 8
·期 10
·2624-2635
·
IF 5.365
Jingxia Tian,Wei Chen,Peng Wu,Zhirong Zhu,Xiaohong Li
A Cux–Mgy–Zrz/SiO2 catalyst with a total metal loading of 60 wt% prepared by a deposition–precipitation method was applied for the selective hydrogenation of ethylene carbonate to methanol and ethylene glycol in a fixed-bed reactor. As a result, the Cu8–Mg1–Zr0.47/SiO2 catalyst furnished 99% ethylene carbonate conversion with 85% selectivity to methanol and 99% selectivity to ethylene glycol under the optimized reaction conditions. Moreover, the Cu8–Mg1–Zr0.47/SiO2 catalyst also showed a good lifetime and neither the activity nor the selectivity decreased the during 208 h test. The reaction was found to depend sensitively on the Cu particle size, the surface acidity and the catalyst surface composition. The synergistic effect of balanced Cu0 and Cu+ sites was considered to play a critical role in attaining high yields of methanol and ethylene glycol. Boric oxide also had a positive effect on the hydrogenation of ethylene carbonate, affording higher selectivity to methanol under much milder conditions.
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