INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
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IF 4.939
Shan Yuan,Lili Cui,Xingquan He,Wei Zhang,Tewodros Asefa
Developing highly active, stable and sustainable electrocatalysts for overall water splitting is of great importance to generate renewable H 2 for fuel cells. Herein, we report the synthesis of electrocatalytically active, nickel foam-supported, spherical core-shell Fe-poly(tetraphenylporphyrin)/Ni-poly(tetraphenylporphyrin) microparticles (FeTPP@NiTPP/NF). We also show that FeTPP@NiTPP/NF exhibits efficient bifunctional electrocatalytic properties toward both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Electrochemical tests in KOH solution (1 M) reveal that FeTPP@NiTPP/NF electrocatalyzes the OER with 100 mA cm −2 at an overpotential of 302 mV and the HER with 10 mA cm −2 at an overpotential of 170 mV. Notably also, its catalytic performance for OER is better than that of RuO 2 , the benchmark OER catalyst. Although its catalytic activity for HER is slightly lower than that of Pt/C (the benchmark HER electrocatalyst), it shows greater stability than the latter during the reaction. The material also exhibits electrocatalytic activity for overall water splitting reaction at a current density of 10 mA cm −2 with a cell voltage of 1.58 V, along with a good recovery property. Additionally, the work demonstrates a new synthetic strategy to an efficient, noble metal-free-coordinated covalent organic framework (COF)-based, bifunctional electrocatalyst for water splitting.
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JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
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2020
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IF 2.717
Hengdong Ren,Xiangfeng Shu,Zhenying Liu,Jun Zhou,Jialin Ma,Yin Liu,Ling Bing Kong,Fanfei Min,Xichen Shi,Jinjin Han,Xin Yang
A facile in-situ strategy has been developed to synthesize lightweight ultrathin coal-derived carbon-nickel composites (CDC/Ni) with superior microwave absorption performances using anthracite as raw material for the first time. The phase structure and chemical composition were investigated by X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Field emission scanning electron microscopy (FESEM) images indicate that the surface of the composite is covered with layered stripes and a large number of macropores. Transmission electron microscopy (TEM) images show Ni nanoparticle size from 30 to 80 nm. Since the introduction of magnetic nickel increases the magnetic loss and improves impedance matching, the CDC/Ni magnetic composites exhibit excellent microwave absorption performance. Specifically, a minimum reflection loss of −62.51 dB is observed at 15.76 GHz, with an effective absorption bandwidth of 4.08 GHz, while the thickness is only 1.31 mm. The superior microwave absorption performance is mainly attributed to the suitable conductivity of CDC. The presence of the nickel nanoparticles has enabled to achieve impedance matching. Besides, the special morphology and oxygen-containing functional groups also bring out various loss mechanisms. Therefore, such CDC/Ni composites could be potential lightweight high performance microwave absorbing materials. In addition, our strategy is a cleaner and more efficient process to utilize coals.
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Energy Technology
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2020
·Vol. 8
·期 9
·2000205
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IF 3.404
Qiang Liu,Jiaming Wang,Kang An,Siran Zhang,Guilong Liu,Yuan Liu
In view of the dual active sites mechanism of direct ethanol synthesis and the excellent catalytic performance of bimetallic catalysts, a series of Ni–Fe alloy catalysts with different Ni/Fe molar ratios derived from layered double hydroxides (LDHs) precursors are synthesized. During the calcination and reduction process of LDHs precursors, the Ni–Fe alloy is obtained, and attributed to all the elements being evenly dispersed at the atomic level in the LDHs precursors; meanwhile, a strong interaction between Ni–Fe alloy and MgAl 2 O 4 support exists. As a result, Ni–Fe alloy nanoparticles are highly dispersed on the MgAl 2 O 4 surface. The high CO adsorption ability on the Ni–Fe alloy and synergism catalysis between Ni and Fe result in excellent catalytic activity and high selectivity to ethanol on the bimetallic Ni–Fe alloy. In addition, the strong antisintering ability and stable alloy structure bring about a good catalytic stability. This research proposes a new catalytic system for direct ethanol synthesis from syngas.
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RARE METALS
·
2020
·Vol. 40
·期 2
·374-382
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IF 2.161
He Si-Ru,Zou Jian-Peng,Chen Li-Bao,Chen Yue-Jiao
Abstract In this work, nickel/T-Nb 2 O 5 nanoparticles encapsulated in mesoporous carbon nanofibers (denoted as Ni/T-Nb 2 O 5 @CNFs) are successfully prepared through a simple electrospinning route and succedent heating treatment. The presence of Ni in carbon nanofibers is beneficial for enhancing the electronic conductivity and the initial Coulombic efficiency. Ni/T-Nb 2 O 5 nanoparticles are homogeneously incorporated in carbon nanofibers to form a nanocomposite system, which provides effective buffering during the lithiation/delithiation process for cycling stability. The Ni/T-Nb 2 O 5 @CNFs show high surface area (26.321 m 2 ·g −1 ) and mesoporous microstructure, resulting in higher capacity and excellent rate performance. The Ni/T-Nb 2 O 5 @CNFs exhibit a remarkable capacity of 437 mAh·g −1 at a current density of 0.5 A·g −1 after 230 cycles and a capacity of 173 mAh·g −1 at a current density up to 10.0 A·g −1 after 1400 cycles. This work indicates that nickel/T-Nb 2 O 5 nanoparticles encapsulated in carbon nanofibers can be a promising candidate for anode material in high-power LIBs. Graphic abstract
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JOURNAL OF POWER SOURCES
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2020
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IF 8.247
Zhiyong Huang,Lijun Fan,Nianjun Hou,Tian Gan,Juanjuan Gan,Yicheng Zhao,Yongdan Li
Ni–Ce 0.8 Pr x Sm 0.2-x O 2-δ (x = 0–0.15) is studied as an anode of solid oxide fuel cells. The doping of Pr facilitates the chemical oxidation of CH 3 OH on the ceramic phase because the strength of Pr–O bond is weaker than that of Ce–O bond. With the addition of Pr, the electronic conductivity of the ceramic phase increases in an oxidizing atmosphere but decreases in a reducing atmosphere. The electrochemical conductivity relaxation results indicate that Pr improves oxygen surface exchange coefficient and oxygen chemical diffusion coefficient of Ce 0.8 Sm 0.2 O 2-δ simultaneously. The doping of Pr shows negligible influence on the performance of the cell fed with H 2 due to the high reactivity of H 2 . However, the maximum power density of the cell with methanol as the fuel increases significantly with the addition of Pr in the anode, demonstrating the high importance of the oxygen activity of the anode when a less active fuel is used. A Ce 0.8 Sm 0.2 O 2-δ -carbonate electrolyte-supported single cell with Ni–Ce 0.8 Pr 0.1 Sm 0.1 O 2-δ anode shows a maximum power density of 792 mW cm −2 at 650 °C with methanol as the fuel.
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ELECTROCHIMICA ACTA
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2020
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IF 6.215
Xue Li,Mingli Fan,Dandan Wei,Maoguo Li,Yinling Wang
Pristine metal organic frames (MOFs) have emerged directly as the electrocatalysts for oxygen evolution reaction (OER). However, the OER performance needs further improvement and the real active sites remain exclusive. Herein, the effect of ligands on the performance of MOFs and the real active sites of each MOFs were explored. Specifically, three Ni based metal organic frames (Ni-MOFs) with different ligands including formic acid (FA), 1,4-benzenedicarboxylic acid (BDC) and 1,3,5-benzenetricarboxylic (BTC) were prepared by a solvothermal method . The morphology, specific surface area, porosity, wettability, electrochemically surface area (ECSA) of each Ni-MOFs were tested. However, none of them could be well correlated to the OER performance except the content of Ni(OH) 2 on the surface from XPS test. Moreover, the OER performance of each Ni-MOF could be improved by cyclic voltammetry (CV) and chronopotentiometry (CP). The morphology and composition of each Ni-MOF before and after electrochemical activation further reveal the real active sites of three Ni-MOFs investigated here were Ni(OH) 2 . These results were expected to provide useful information for designing more excellent OER electrocatalysts based on MOFs.
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MATERIALS CHEMISTRY AND PHYSICS
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2020
·
IF 3.408
Yu Chen,Jin Guo,Minyi Lu,Bo Liang
A novel Ni–Fe nanosheets catalyst supported on α-Al 2 O 3 foam ceramic was synthesized by a hydrothermal method and used to obtain multi-walled carbon nanotubes (MWNTs) via the propane partial oxidation . Catalytic performance tests were carried out at 600 °C and atmospheric pressure using a fixed-bed reactor. The synthesized catalysts and carbon materials were analyzed using various characterization methods. According to the field emission scanning electron microscope (FESEM) results, the catalyst morphology was a 3D grid structure consisting of nanosheets 800 nm length and 80 nm width. Additionally, the quantity and quality of the carbon nanotubes were greatly influenced by different oxygen-to-propane molar ratios, defined as the equivalence ratio ϕ (ϕ = 1.5, 1.78, 2). Transmission electron microscope (TEM) images showed that carbon nanotubes over all catalysts were MWNTs. In addition, the thermogravimetric analysis and Raman data showed that a high yield of MWNTs was obtained at ϕ = 1.78, but the accumulated MWNTs at ϕ = 1.5 exhibited a higher degree of graphitization (I D /I G = 0.89) compared with the other two equivalence ratios.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 31
·期 13
·10489-10498
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IF 2.22
Wang Shitong,Wang Jiemei,Ji Xiang,Meng Jiaxi,Sui Yanwei,Wei Fuxiang,Qi Jiqiu,Meng Qingkun,Ren Yaojian,He Yezeng,Zhuang Dongdong
Metal hydroxide serving as a promising electrode material for the supercapacitors, has attracted considerable interests in the area of energy storage. However, the low cycling stability and electrical conductivity restrict its further application. Here, a kind of hollow-cubic Ni(OH) 2 /CuS 2 with excellent electrochemical performance has been prepared via a facile one-step sacrificial template method. The obtained Ni(OH) 2 /CuS 2 shows an outstanding specific capacitance of 1174 F g −1 at 1 A g −1 with 73.9% retention after 2000 charge–discharge cycles. Furthermore, the assembled asymmetric supercapacitors based on hollow-cubic Ni(OH) 2 /CuS 2 nanocomposite and reduced graphene oxide (RGO) exhibits a high specific energy density of 27.8 Wh kg −1 at the power density of 390 W kg −1 .
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ACS Sustainable Chemistry & Engineering
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2020
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IF 7.632
Xuemei Li,Junying Tian,Hailong Liu,Xun Hu,Jia Zhang,Chungu Xia,Jing Chen,Haichao Liu,Zhiwei Huang
The reductive amination (RA) of 2-hydroxytetrahydropyran (2-HTHP) produced from biofurfural-derived dihydropyran provides a new efficient process for the clean synthesis of valuable 5-amino-1-pentanol (5-AP). Among various solid catalysts tested, the inexpensive Ni–Mg3AlOx catalysts derived from hydrotalcite precursors were found to be very active and selective, especially at Ni loadings above 20 wt %. A 85% total yield of 5-AP was obtained from dihydropyran on 40Ni–Mg3AlOx, the catalyst with the highest 2-HTHP RA activity among the Ni–Mg3AlOx catalysts, under mild conditions of 60 °C and 2 MPa H2. Characterization results showed that the reducibility of the calcined NiO-Mg3AlOx samples increased with increasing Ni loading from 5 to 50 wt %, while the Ni0 crystallite sizes exhibited a minimum of 4.8 nm on 40Ni–Mg3AlOx after reduction in H2 at 750 °C. The volcanic changes of 5-AP generation rate/yield with increasing Ni loading of the Ni–Mg3AlOx catalysts and with rising prereduction temperature of 30Ni–Mg3AlOx catalyst in 2-HTHP RA indicate that the balance of the reducibility and Ni0 particle size of the catalysts played an important role in obtaining high 5-AP yields. The 30Ni–Mg3AlOx catalyst showed a good stability in 2-HTHP RA examined in a continuous flow reactor over a 90 h time-on stream.
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Journal of Energy Chemistry
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2020
·
IF 7.216
Jia Sun,Lei Du,Baoyu Sun,Guokang Han,Yulin Ma,Jiajun Wang,Hua Huo,Pengjian Zuo,Chunyu Du,Geping Yin
ABO 3 -type perovskite oxides (e.g., LaCoO 3 ) with flexible and adjustable A- and B-sites are ideal model catalysts to unravel the relationship between the electronic structure and electrocatalytic activity (e.g., oxygen reduction/evolution reactions, ORR/OER). It has been well understood in our recent work that the secondary metal dopant at B-site (e.g., Mn in LaMn x Co 1 −x O 3 ) can regulate the electronic structure and improve the ORR/OER activity. In this work, the Mn-Ni pairs are employed as the dual dopant in LaMn x Ni y Co z O 3 ( x + y + z = 1) catalysts toward bifunctional ORR and OER. The structure–property relationships between the triple metal B-site (Mn, Ni and Co) and the electrochemical performance are particularly investigated. Compared to the individual Mn doping (e.g., LaMnCoO 3 (Mn:Co = 1:3) catalyst), the dual Mn-Ni doping significantly improves the ORR mass activity@0.8 V by 1.54 times; meanwhile, the OER overpotential@10 mA cm −2 is reduced from 420 to 370 mV, and the OER current density at 1.55 V is increased by 2.43 times. Reasonably, the potential gap between E ORR @-1 mA cm −2 and E OER @10 mA cm −2 is achieved as only 0.76 V by using the optimal LaMn x Ni y Co z O 3 ( x : y : z = 1:2:3) catalyst. It is revealed that the dual Mn-Ni dopant efficiently optimizes electron structures of the LaMnNiCoO 3 (1:2:3) catalyst, which not only decreases the e g orbital electron number, but also modulates the O 2p-band closer to the Femi level, accounting for the enhanced bifunctional activity.
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CHINESE CHEMICAL LETTERS
·
2020
·
IF 4.632
Guangmeng Qu,Xixi Zhang,Guotao Xiang,Yunrui Wei,Jiangmei Yin,Zonghua Wang,Xiaoli Zhang,Xijin Xu
Nano-polyhedral NiSe 2 /CoSe 2 (Ni-Co-Se) with hollow architectures are synthesized by selenizing the precursors of Ni-Co bimetallic hydroxides that are directly derived from ZIF-67. The as-fabricated Ni-Co-Se electrodes exhibit high specific capacitance of 1668 F/g at 1 A/g accompanying with outstanding rate capability (about 82.8% retention of the initial capacity at 20 A/g). The corresponding Ni-Co-Se//AC all-solid-state hybrid supercapacitors are assembled by directly using the Ni-Co-Se on carbon fabric as the positive electrode, which deliver high energy density and power density (38.5 Wh/kg at 802.1 W/kg, 32.0 Wh/kg at 8008.8 W/kg), excellent cyclic stability (82.3% retention after 5000 cycle) and robust mechanical flexibility (no obvious attenuation at bending to different angles). This work will provide a new and smart route for constructing transition metal selenides for supercapacitor devices.
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Energy Technology
·
2020
·Vol. 8
·期 5
·1901310
·
IF 3.404
Muhammad Sohail Riaz,Siwei Zhao,Chenlong Dong,Muhammad Javed Iqbal,Yantao Zhao,Fuqiang Huang
Heterostructure transition metal derivatives have been extensively studied in electrocatalysis, but most of the hybrid samples are on nanoscale with low stability and tap density. ZnO microspheres are applied as a sacrificial template, followed by alkaline etching and aluminum reduction to construct Ni/Co 3 O 4 microcubes. The porous hybrid microcubes show stirring performance in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For HER, it exhibits comparable overpotential of 145 mV at 10 mA cm −2 as Pt/C (101 mV) and desirable stability. For OER, it outperforms RuO 2 with lower overpotential when the current exceeds 17.8 mA cm −2 and much smaller Tafel slope of 34 mV dec −1 versus RuO 2 (72 mV dec −1 ). The potential activity is assigned to the charge transfer at the heterointerfaces, and the synergic effects of the Ni/Co 3 O 4 phases, which possibly will cast light on the design of microscale bifunctional electrocatalysts.
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