Science China-Materials
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2023
·Vol. 66
·期 7
·2803-2811
·
IF 8.1
Cheng Haoran,Pan Yamin,Wang Tiecheng,Zhou Yang,Qin Yijing,Liu Chuntai,Shen Changyu,Liu Xianhu
Ingenious microstructural design and suitable multicomponent strategy remain challenging for efficient absorption-dominated electromagnetic interference (EMI) shielding materials with light weight, low filling levels and thin sample thickness. Herein, a flexible waterborne polyurethane (WPU)/dielectric carbon nanotube (CNT)/magnetic anisotropic Ni (chain or flower) EMI shielding composite sponge based on the unique shielding capsule structure was constructed by a dip-coating process. The results show that increasing the Ni (flower or chain) filler content significantly improves the electrical conductivity and EMI shielding properties of composites. The EMI shielding performances of WPU/CNT/8 wt% Ni flower-melamine foam (MF) and WPU/CNT/8 wt% Ni chain-MF are 42.8 and 46.7 dB, respectively, which exceed those of the composite sponge with only CNTs. The synergistic effect between CNTs and Ni (flower or chain) means that the main EMI shielding mechanism of the composite sponge comes from the absorption process. Importantly, owing to the protection of the WPU layer, the composites exhibit excellent EMI shielding effectiveness (SE) even under severe physical and chemical degradation. This research provides a simple synergistic approach for the design of novel, lightweight, and efficient EMI shielding composites, which show great promise for applications in portable and wearable electronic devices.
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ACS Applied Energy Materials
·
2023
·
IF 6.4
Hua Yang,Yi Duan,Huiling Gu,Lihua Liu,Hongtao Guan,Chengjun Dong,Gang Chen
Metal–organic frameworks (MOFs) with porous structures are beneficial for electrochemical energy storage. Herein, the in-situ growth of the S-doped Ni-MOF nanosheet (S-NMN) on the surfaces of nickel foams was prepared via a facile solvothermal process. Owing to the rich active sites, small transport barrier, and excellent mechanical stability, the fabricated S-NMN-2 electrode displays a high specific capacity (1952 mF cm–2 at 1 mA cm–2), satisfactory rate performance, and remarkable cyclic stability. For practical application, the assembled S-NMN-2//AC device achieves a high energy density of 0.189 mWh cm–2 at the power density of 1.600 mW cm–2 with prominent cycling stability (93.27% capacity retention after 4000 cycles). The facile strategy of etching nickel foam demonstrates a new idea for developing high-performance supercapacitor materials.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Xin Ning,Heming Wang,Ganghua Zhou,Longyun Zhang,Yanju Yang,Jingya Sun,Xiaozhi Wang
Ni catalysts decorated with trace Rh supported on γ-Al2O3 were prepared by the co-impregnation method. To obtain the Ni–Rh nanoparticles with different nanostructures and chemical compositions, bimetallic catalysts with varied Ni/Rh molar ratios were prepared. For comparison, monometallic Ni/γ-Al2O3 and Rh/γ-Al2O3 catalysts were also prepared by the impregnation method. The selective gas phase catalytic hydrodechlorination of 1,2-dichloroethane to ethylene was used to evaluate catalytic performances of the catalysts. The catalysts were characterized by X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, transmission electron microscopy–energy-dispersive X-ray, and CO chemisorption. It was found that the introduction of Rh to Ni catalyst facilitated the generation of spillover hydrogen which could enhance the ability of the Ni catalyst for H2 activation. In bimetallic catalysts, there was an intimate interaction between Ni and Rh, and isolated Rh sites were formed due to the dilution effect of Ni. Accordingly, compared with the monometallic Ni catalyst for gas phase catalytic hydrodechlorination of 1,2-dichloroethane, the bimetallic Ni–Rh(800)/γ-Al2O3 catalyst exhibited markedly higher 1,2-dichloroethane conversion (37%) and comparable selectivity to ethylene (95%). The findings in this study indicate that Ni–Rh/γ-Al2O3 with trace Rh can be used as a promising catalyst for highly effective and selective catalytic hydrodechlorination of chlorinated hydrocarbons.
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Small
·
2023
·Vol. 19
·期 12
·2207197
·
IF 13.3
Bei Li,Ziqian Ma,Xiao Zhang,Jia Xu,Yujin Chen,Xitian Zhang,Chunling Zhu
Hollow carbon spheres are potential candidates for lightweight microwave absorbers. However, the skin effect of pure carbon-based materials frequently induces a terrible impedance mismatching issue. Herein, small-sized NiO/Ni particles with heterojunctions on the N-doped hollow carbon spheres (NHCS@NiO/Ni) are constructed using SiO 2 as a sacrificing template. The fabricated NHCS@NiO/Ni displayed excellent microwave absorbability with a minimum reflection loss of −44.04 dB with the matching thickness of 2 mm and a wider efficient absorption bandwidth of 4.38 GHz with the thickness of 1.7 mm, superior to most previously reported hollow absorbers. Experimental results demonstrated that the excellent microwave absorption property of the NHCS@NiO/Ni are attributed to balanced dielectric loss and optimized impedance matching characteristic due to the presence of NiO/Ni heterojunctions. Theoretical calculations suggested that the redistribution of charge at the interfaces and formation of dipoles induced by N dopants and defects are responsible for the enhanced conduction and polarization losses of NHCS@NiO/Ni. The simulations for the surface current and power loss densities reveal that the NHCS@NiO/Ni has‑ applicable attenuation ability toward microwave under the practical application scenario. This work paves an efficient way for the reasonable design of small-sized particles with well-defined heterojunctions on hollow nanostructures for high-efficiency microwave absorption.
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PubMed
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CATALYSIS COMMUNICATIONS
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2019
·
IF 3.674
Wei Wang,Feng Xu,Wenqiao Du,Long Zhang
A facile and efficient one-pot synthesis of methyl carbamate (MC) by urea and methanol was studied using metal modified fluorapatite as a catalyst. M 5 Ca 5 (PO 4 ) 6 F 2 (M 5 FAP, M = Co, Ni, Cu, Zn) was synthesized by co-precipitation. Among the catalysts, Zn 5 Ca 5 (PO 4 ) 6 F 2 (Zn 5 FAP) displayed the higher activity, selectivity and excellent stability after five times of reuse. A possible synthesis reaction mechanism over Zn 5 FAP catalyst was discussed.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Jianshuo Zhang,Kun Hou,Qianqian Yao,Chuxin Wu,Meihua Huang,Lunhui Guan
Transition metal phosphides represent a class of promising electrocatalysts for electrochemical water oxidization and other energy conversion reactions. In this work, we report a novel seal strategy, followed by a second step phosphorization treatment, produces Ni-Fe-P heterostructure directly grown on nickel foam that shows highly catalytic activity for electrochemical water oxidation . The as-prepared catalyst exhibits an excellent electrocatalytic activity , manifested by a current density of 20 mA cm −2 with a very low overpotential (260 mV) for oxygen evolution reaction along with an extremely small Tafel slope of 27 mV decade −1 and a very excellent durability of 120 h in alkaline solution. The excellent performance with exceptional durability owe much to the synergistic effect between the Ni-Fe-P heterostructure and the outer oxidized layer. Remarkably, a current density of 10 mA cm −2 was reached at a low cell voltage of 1.63 V when the original electrode and surface oxidized electrode are used as cathode and anode , respectively.
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ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Jingwei Li,Peiman Xu,Rongfu Zhou,Ruchun Li,Lijun Qiu,San Ping Jiang,Dingsheng Yuan
Large-scale commercialization of water splitting is still challenging due to the lack of efficient, cost-effective and robust electrodes. In this work, Co 9 S 8 –Ni 3 S 2 heterointerfaced nanotubes on Ni foam (Co 9 S 8 –Ni 3 S 2 HNTs/Ni) have been successfully developed via a two-step hydrothermal method as a highly efficient, robust and flexible bifunctional electrodes for water splitting. Co 9 S 8 –Ni 3 S 2 HNTs are composed of inner 1D Co 9 S 8 nanotubes surrounded by outer 2D Ni 3 S 2 nanosheets . Co 9 S 8 –Ni 3 S 2 HNTs/Ni electrode achieves 10 mA cm −2 at overpotentials of 85 mV for H 2 evolution reaction (HER) and 50 mA cm −2 at overpotential of 281 mV for O 2 evolution reaction (OER) in 1 M KOH solution, substantially better than that on single-phased Co 9 S 8 nanotubes and Ni 3 S 2 nanosheets on Ni foam. The reason is most likely due to formation of defect-rich heterointerfaces between Co 9 S 8 nanotubes and Ni 3 S 2 nanosheets, and the significant change of binding energies of Co 2p and Ni 2p level between the Co 9 S 8 and Ni 3 S 2 , leading to the synergistic effect on the enhanced catalytic activity for HER and OER. The robust and flexibility of Co 9 S 8 –Ni 3 S 2 HNTs/Ni electrodes are demonstrated in an alkaline electrolyzer, delivering 10 mA cm −2 electrolysis current at a cell voltage of 1.59 V, one of the best bifunctional electrodes for water splitting. Owing to the fact that reaction occurs at the defects-rich heterointerfaces, the Co 9 S 8 -Ni 3 S 2 HNTs/Ni electrodes are structurally very stable.
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NANO
·
2019
·
IF 1.293
Yanwei Sui,Man Zhang,Haihua Hu,Yuanming Zhang,Jiqiu Qi,Fuxiang Wei,Qingkun Meng,Yezeng He,Yaojian Ren,Zhi Sun
The interconnected three-dimensional Ni–Co–S nanosheets were successfully deposited on ZnO nanorods by a one-step potentiostatic electrodeposition. The Ni–Co–S nanosheets provide a large electrode/electrolyte interfacial area which has adequate electroactive sites for redox reactions. Electrochemical characterization of the ZnO@Ni–Co–S core–shell nanorods presents high specifc capacitance (1302.5 F/g and 1085 F/g at a current density of 1 A/g and 20 A/g), excellent rate capabilities (83.3% retention at 20 A/g) and great cycling stability (65% retention after 5000 cycles at a current density of 30 A/g). The outstanding electrochemical performance of the as-prepared electrode material also can be ascribed to these reasons that the special structure improved electrical conductivity and allowed the fast diffusion of electrolyte ions.
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ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Aijuan Xie,Jie Zhang,Xiang Tao,Jianghui Zhang,Bingyan Wei,Wenhao Peng,Yuwei Tao,Shiping Luo
Nickel-based metal organic framework materials were first prepared by hydrothermal method and used as the precursor. Ni/nitrogen-carbon (Ni–N–C), Ni@NiO–N–C and NiO–N–C mixtures derived from metal organic skeleton were successfully prepared by controlling the heat treatment conditions and applied in the electrocatalytic oxygen evolution reaction (OER). Through a series of research of OER catalytic performance, OER process kinetics, and stability, the as-prepared Ni @ NiO/N–C nanowires (NW) (250 °C) with core-shell structure showed the most prominent activity. Compared with other derived mixed materials, the oxygen evolution overpotential was 390 mV at the current density of 10 mA cm −2 , and the Tafel slope was 100 mV dec −1 . Moreover, the material showed excellent stability without significant decrease of activity after a long time of testing. The detail study regarding the formation and evolution of Ni/NiO NWs is of considerable value and may offer prospects for developing highly active electrocatalysts in electrochemical energy devices.
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NANOTECHNOLOGY
·
2019
·Vol. 30
·期 41
·415602
·
IF 3.399
Na Wang,Min Zhang,Libin Liu,Jing Zheng,Jingli Xu,Tasawar Hayat,Njud S. Alharbi
A unique nanostructure of Fe3O4 nanoparticles (NPs)-in/carbon layer/out-Ni NPs was developed and proved to be an efficient catalyst and protein adsorbent. This kind of nanostructure was formed through a space-confined pyrolysis procedure using polydopamine-Ni2+ coated Fe-NTA nanowires as the precursor. A N-doped carbon interlayer derived from polydopamine (PDA) supported a large amount of Ni NPs and entrapped well-defined Fe3O4 NPs, which were obtained through reduction of Ni2+, Fe3+ by carbonized NTA groups and a PDA layer. The contributions of the unique configuration along with the high density of Ni NPs in Fe3O4@C-Ni are significant for improving catalysis and protein adsorption performance, which is expected to be a promising alternative to other conventional catalysts and protein adsorbents. Due to the unique novel nanostructure, this nanocomposite possesses a wide range of applications, not only for catalytic reactions but also for other inhomogeneous reactions.
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Catalysts
·
2019
·Vol. 9
·期 8
·632
·
IF 3.444
Kirill Alferov,Shuanjin Wang,Tianhao Li,Min Xiao,Shanyue Guan,Yuezhong Meng
Synthesis of copolymers from carbon dioxide (CO2) and epoxides is an important research direction as such processes utilize the abundant greenhouse gas and deliver useful products. Specifically, cooligomers of CO2and propylene oxide (PO) with a non-alternating structure can be used for polyurethane preparation. They are synthesized by employing Zn-Co cyanide catalysts. The application of alternative metal cyanide complexes is interesting from scientific and practical points of view. The purpose of this work was to study the copolymerization of CO2and PO in the presence of Co-Ni cyanide catalysts and chain transfer agents (CTAs) in order to obtain low molecular weight products. Three Co-Ni catalysts with different contents of complexing agents were synthesized, characterized by several analytical methods and applied for this reaction. The complex without complexing agents was chosen for detailed investigation. 1,6-Hexanediol proved to be a more preferred CTA than poly(propylene glycol) and adipic acid. An oligo(ethercarbonate) (Mn= 2560, PDI = 2.5, CO2= 20 mol.%) capped with OH groups was synthesized with relatively high productivity (1320 gPO+CO2/gcatin 24 h) and characterized by matrix-assisted laser desorption/ionization (MALDI) MS and NMR methods. The main chain transfer routes during the cooligomerization were suggested on the basis of the research results.Keywords:metal cyanide catalyst;cobalt;nickel;carbon dioxide;propylene oxide;copolymerization;chain transfer agent;oligo(ethercarbonate);polyurethanes
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Green Energy & Environment
·
2019
·
IF 0
Xiaolan Deng,Yuqi Jiang,Zengxi Wei,Minglei Mao,Ramyakrishna Pothu,Hongxia Wang,Caiyun Wang,Jinping Liu,Jianmin Ma
Increasing the energy density, power density as well as widening the operation voltage are essential to electrochemical capacitors to meet the practical energy demands. Herein, a novel flexible quasi-solid-state dual-ion asymmetric supercapacitor (ASC) with Ni(OH) 2 and Nb 2 O 5 nanosheets directly grown on stainless steel mesh is developed. In the dual-ion ASC, Nb 2 O 5 negative and Ni(OH) 2 positive electrodes react with Li + and OH − respectively in alkaline gel electrolyte to store energy, which is quite different from conventional alkali metal ion SCs and alkaline SCs. The as-assembled flexible device has an extended working voltage of 1.7 V and delivers a capacity of 5.37 mAh cm −2 , a maximum energy density and power density of 0.52 mWh cm −3 and 170 mW cm −3 , respectively. The device maintains around 60% capacity retention after long cycling up to 1000 cycles. Moreover, our device can light up a LED light efficiently upon fast charging. The proposed quasi-solid-state dual-ion ASC has potential applications in future portable electronics and flexible energy storage devices.
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