RENEWABLE ENERGY
·
2021
·
IF 8.001
Jianmei Cen,Enjun Jiang,Yuqing Zhu,Zhenyu Chen,Panagiotis Tsiakaras,Pei Kang Shen
Herein, two novel electrocatalysts are simultaneously grown on Ni foam (NF) through a one-step hydrothermal method . The as-prepared Ru–MoO 3- x NF exhibits good performance for HER with low overpotentials of 12 mV at 10 mA cm −2 and 49 mV at 100 mA cm −2 , a low Tafel slope of 32.96 mV dec −1 , as well as an excellent durability at least lasting 17 h in alkaline media . The Fe 3 O 4 –NiFe LDH NF (layered double hydroxide nickel foam) ultrathin nanosheets electrode shows a low OER overpotential of 216 mV at 10 mA cm −2 and a small Tafel slope of 42.42 mV dec −1 . Moreover, a two-electrode water splitting device is fabricated with Ru–MoO 3- x NF as cathode and Fe 3 O 4 –NiFe LDH NF as anode, it only requires 1.46 V at 10 mA cm −2 and exhibits a long term durability without obvious loss of activity after continuously operating for 180 h. The superior catalytic behavior should be originated from the open heterostructure and oxygen vacancies with high intrinsic activity, abundant exposed active sites, and fast charge transfer. This work provides a new strategy to design heterostructure and transition metal oxides catalysts with improved catalytic activity and durability by a facile route for overall water splitting or other applications.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 9
·3031
·
IF 3.748
Shijing Zhao,Wenju Zhou,Xiaojun Xiang,Xuyan Cao,Ning Chen,Weifeng Chen,Xiaohui Yu,Bingmin Yan,Huiyang Gou
The precise determination of atomic position of materials is critical for understanding the relationship between structure and properties, especially for compounds with light elements of boron and single or multiple transition metals. In this work, the single crystal X-ray diffraction is employed to analyze the atomic positions of Co2MoB4and Fe2MoB4with a Ta3B4-type structure, and it is found that the lengths of B-B bonds connecting the two zig-zag boron chains are 1.86 Å and 1.87 Å, but previously unreported 1.4 Å. Co and Fe atoms occupy the same crystallographic position in lattice for the doped samples and the valence is close to the metal itself, and Co/Fe K-edge X-ray Absorption Fine Structure(XAFS) spectra of borides with different ratios of Co to Fe are collected to detect the local environment and chemical valence of Co and Fe. Vickers hardness and nano indentation measurements are performed, together with the Density Functional Theory (DFT) calculations. Finally, Co2MoB4possess better thermal stability than Fe2MoB4evaluated by Thermogravimetric Differential Thermal Analysis (TG-DTA) results.Keywords:transition metal boride;hardness;XAFS;thermal stability
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
PubMed
高影响因子
Nanomaterials
·
2020
·Vol. 10
·期 11
·2115
·
IF 4.324
Yuan Gao,Ka Wang,Zixia Lin,Haizeng Song,Xiaomeng Duan,Zehui Peng,Shancheng Yan
Transition metal sulfides are cheap and efficient catalysts for water splitting to produce hydrogen; these compounds have attracted wide attention. Nickel sulfide (NiS2) has been studied in depth because of its simple preparation process, excellent performance and good stability. Here, we propose a modification to the hydrothermal synthesis method for the fabrication of a highly efficient and stable NiS2electrocatalyst prepared by two different sulfur sources, i.e., sulfur powder and C3H7NaO3S2(MPS), for application in hydrogen evolution reactions. The obtained NiS2demonstrated excellent HER performance with an overpotential of 131 mV to drive -10 mA cm−1in 0.5 M H2SO4solution with 5mV performance change after 1000 cycles of stability testing. We believe that this discovery will promote the industrial development of nonprecious metal catalysts.Keywords:transition metal sulfide;hydrogen evolution reaction;electrocatalyst
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Tianping Huang,Jianxin Zou,Huabing Liu,Wenjiang Ding
Three kinds of transition metal fluorides TMF x (TM = Nb, Co, Ti) were introduced into the 3NaBH 4 -GdF 3 hydrogen storage system via mechanical milling. Their effects on the hydrogen storage behaviors of 3NaBH 4 -GdF 3 were systematically investigated by means of DSC and volumetric methods. All TMF x exhibited promoting effect on hydrogen desorption properties of 3NaBH 4 -GdF 3 to different degrees, especially when NbF 5 or TiF 3 was added. For example, the hydrogen desorption peak temperature was decreased by 17 °C with doping 3 mol% of NbF 5 . Besides, TiF 3 improved also the hydrogen absorption capacity and reversibility of 3NaBH 4 -GdF 3 . Based on XRD analyses, the role of TMF x on the dehydrogenation and the promoting effect of TiF 3 on the reversibility of 3NaBH 4 -GdF 3 were clarified. This work helped to understand the combination effect of rare earth metal fluoride (GdF 3 ) and transition metal fluorides on the reversible hydrogen storage properties of NaBH 4 .
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2016
·Vol. 3
·期 8
·1048-1057
·
IF 4.532
Hao Zhang,Xiaofeng Wang,Chengcheng Chen,Cuihua An,Yanan Xu,Yanying Dong,Qiuyu Zhang,Yijing Wang,Lifang Jiao,Huatang Yuan
We herein report a facile method for synthesizing a series of metal oxides from the mixture of oleylamine and metal nitrates with heating at 180 °C. Several diverse nanoparticles with various morphologies are gained expectedly: 16.5 nm Mn3O4 nano-capsules, 22 nm CoO nano-cubes, 35 nm NiO nano-flowers and 4 nm Fe3O4 quantum dots. This method is convenient for preparing the dispersed nanoparticles at mild reaction temperature with low-cost metal sources. As-prepared CoO nano-cubes are employed as the electrode material of a pseudocapacitor in terms of implementation. The specific capacitance reaches a stable level of 750 F g−1. This material also exhibits a superior performance in high rate capability and maintains an excellent stability during 9000 recycles. The asymmetric supercapacitor device with a maximum voltage of 1.7 V is fabricated using CoO nano-cubes as the positive and activated carbon as the negative electrode.
研究领域:
材料科学
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纳米技术
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电化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Kaixuan Feng,Ruixiang Lin,Tingyu Chen,Yuyan Hu,Yuheng Feng,Dezhen Chen,Mudassir Hussain Tahir,Tongcheng Cao
In this study, a catalytic system for N 2 O reduction by H 2 onto char decorated with transition metals is proposed, which have excellent reduction efficiency at low temperatures below 200 °C and efficiently utilizes pyrolysis char and hydrogen. Density functional theory (DFT) is used to reveal the reaction mechanism and found that transition metal decoration can significantly promote reaction rate and decrease the activation energy required for N 2 O reduction by H 2 on char, from 383.7 kJ/mol to 50–160 kJ/mol. Furthermore, transition states in the process of reducing N 2 O by H 2 over metal-char were observed, including reduction of N 2 O and the removal of the surface oxygen complex. Through kinetic analysis , the activation energy and reaction rate order was found as Ni-char (50.0 kJ/mol)>Co-char (95.1 kJ/mol)>Fe-char (151.0 kJ/mol)>Cu-char (158.8 kJ/mol). According to experiments phenomenon, the sequence of reduction efficiency over different metal-char was consistent with the simulation results and it was even possible to convert N 2 O to N 2 below 200 ℃. This research contributes to a more mechanistic understanding of the N 2 O-H 2 reaction over char and provides new insights for improving the design of catalysts for N 2 O abatement at low temperatures.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
Asian Journal of Organic Chemistry
·
2023
·Vol. 12
·期 5
·e202300015
·
IF 2.7
Yu-Tong Duan,Zhong-Xia Wang
Graphical Transition-metal-free reaction of oxindoles with primary or secondary alcohols in the presence of LiO t Bu affords α-C-alkylated oxindoles. Transition-metal-free α-C-alkylation of oxindoles with alcohols was performed. The reaction requires the presence of LiO t Bu and proceeds under thermal conditions. The method exhibits a wide scope of substrates. Both primary and secondary aliphatic and aromatic alcohols can be employed as the alkylating reagents. Oxindole and various 1-alkyl- or 1-aryl-substituted oxindoles can be alkylated. The mechanistic studies show that the reaction may involve both free radical and aldol condensation/MPV processes.
研究领域:
有机化学
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合成化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2023
·
IF 3.7
Lirong Lv,Zhongguo Zhang,Sheng Wang,Yue Shan,Liangliang Wang,Tongzhou Xu,Peiran He
A series of Y Ce catalysts were prepared using Y-loaded (Y = Cu, Co, Mn) Ce-based metal–organic framework as a precursor. Mn-loaded CeO 2 exhibited significantly better catalytic activity in the catalytic oxidation of ethyl acetate (EA) than noble metal catalyst. The relationship between the physicochemical properties of Y Ce catalysts and catalytic activity was studied by different characterization methods. The enhanced catalytic activity was attributed to the strong interaction between the transition metals and Ce, high specific surface area, abundant lattice defects, more oxygen vacacies and higher O latt /(O latt + O ads + O w ) molar ratios. The main intermediates in the oxidation of EA were ethanol, acetic acid, acetone, acetaldehyde and diethyl ether.
研究领域:
化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2016
·
IF 1.272
Xiang Li,Qian Deng,Zaili Zhang,Xiaoshan Jia
In this study, remediation of tetrabromobisphenol-A (TBBPA) from aqueous solution by sorption using transition metals-modified inorganic–organic montmorillonite (IOMt) was demonstrated. The adsorbents were prepared in two steps: (1) intercalation of surfactants into Al13-pillared montmorillonite for synthesizing two types of IOMt; (2) incorporation of transition metals (Cu2+, Ni2+, or Co2+) onto those IOMts. Firstly, these materials were characterized by XRD, FTIR, TGA, SEM-EDS, and BET analyses. Then, experiments were conducted on the sorption isotherms, kinetics, and thermodynamics of TBBPA. In general, sorption process with Cu- and Ni-modified IOMt achieved higher TBBPA removal efficiency than sorption process with original IOMt. The modified IOMt displayed the sorption capacity that varied depending on TBBPA initial concentration, pH, and metals loading. However, the type of surfactants did not influence TBBPA sorption on metals-modified IOMt. This probably indicated that complex interaction between TBBPA and metals rather than hydrophobicity plays a key factor in TBBPA sorption process. Equilibrium data could be well interpreted by the Freundlich model, and the rate of sorption was adjusted to a pseudo-second-order kinetic model. The negative values of Gibbs energy change (∆G) and positive values of enthalpy change (∆H) indicated the spontaneous and endothermic nature of process.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Yong-Jie Geng,Jie Wang,Zhi-Hong Liu
Two transition metal borates with microporous structures for Na 2 Co 2 B 12 O 21 and Na 2 Cu 2 B 12 O 21 have been synthesized and characterized by XRD, FT-IR, and elemental analysis. The molar enthalpies of solution of Na 2 Co 2 B 12 O 21 (s) and Na 2 Cu 2 B 12 O 21 (s) in 1 mol dm −3 HCl(aq) were measured by microcalorimeter at T = 298.15 K, respectively. The molar enthalpies of solution of CoCl 2 ·6H 2 O(s) and CuCl 2 ·2H 2 O(s) in the mixture solvent of 2.00 cm 3 of 1 mol dm −3 HCl(aq) in which 5.30 mg of H 3 BO 3 and 0.84 mg of NaCl being added were also measured, respectively. With the incorporation of the previously determined enthalpy of solution of H 3 BO 3 (s) in 1 mol dm −3 HCl(aq), together with the standard molar enthalpies of formation for CoCl 2 ·6H 2 O(s)/CuCl 2 ·2H 2 O(s), NaCl(s), H 3 BO 3 (s), HCl(aq) and H 2 O(l), the standard molar enthalpies of formation of – (9072.4 ± 9.7) kJ mol −1 for Na 2 Co 2 B 12 O 21 (s) and – (8887.5 ± 9.7) kJ mol −1 for Na 2 Cu 2 B 12 O 21 (s) at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycles. It is obvious that Na 2 Co 2 B 12 O 21 (s) is more thermal stable than that of Na 2 Cu 2 B 12 O 21 (s).
研究领域:
材料科学
·
热化学
✓ 已验证
DOI
高影响因子
Greenhouse Gases-Science and Technology
·
2024
·
IF 2.7
Fa-Ping Liu,Ai-Rong Li,Cheng Wang,Yu-Ling Ma
CO 2 hydrate technology can be applied to seawater desalination. However, the kinetics of CO 2 hydrate formation were inhibited in the aqueous solution with inorganic salts, and the kinetic mechanism of CO 2 hydrate formation for inorganic salts with different metal cations and anions was still unclear. In this work, CO 2 hydrate nucleation and growth were studied in aqueous solutions of metal chlorides. Instead of Na + and K + ions, CO 2 hydrate nucleation was promoted in the presence of Ni 2+ , Mn 2+ , Zn 2+ and Fe 3+ ions due to the co-ordination bonds between transition metal ions and water molecules to enhance the formation of the critical crystal nuclei. The induction time was increased by 61.1% in aqueous solution with 0.32 mol/L NaCl, while it was shortened by 55.6% in FeCl 3 aqueous solution at the same concentration of Cl − anions. In the process of CO 2 hydrate growth, Cl − ions played a more important role than the metal ions in affecting the stability of CO 2 hydrate cages. The gas storage capacity was reduced by 10.3% in the presence of NaCl, and was lower than that of other metal chlorides. Cl − anions were absorbed on the hydrate surface and involved in hydrate cages to inhibit the hydrate growth due to the hydrogen bonds between the Cl − ions and water molecules of the hydrate cages. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Energy Technology
·
2020
·Vol. 8
·期 5
·2000008
·
IF 3.404
Chengrui Wang,Lei Zhang,Yuhai Dou,Luke Hencz,Lixue Jiang,Mohammad Al-Mamun,Porun Liu,Shanqing Zhang,Dan Wang,Huijun Zhao
Further commercial application of low-cost NiO-based anodes is hindered by their large volume expansion after full lithiation and relatively poor theoretical capacity. To improve these issues, transition metal (Fe, Co, or Mn)-modified triple-shelled NiO microspheres (TS-NiO) are successfully synthesized by using a hard template double-adsorption method. Among them, the Fe-modified TS-NiO (TS-NFO) exhibits an extraordinary lithium storage ability with high reversible capacity and outstanding cycling stability (2061.1 mAh g −1 after 800 cycles at 0.5 A g −1 ), which is the highest performing nickel oxide-based anode reported to date. The outstanding electrochemical performance of TS-NFO can be ascribed to its unique triple-shelled structure. The inner core of TS-NFO is composed of NiO and is encapsulated by two outer shells which are composed of a mixture of α-Fe 2 O 3 and NiFe 2 O 4 , resulting in a unique hollow triple-shelled structure (NiO@α-Fe 2 O 3 /NiFe 2 O 4 ). The void space between the triple shells leaves room for their volume changes during lithiation/delithiation, which improves the cycling stability. In addition, the introduced α-Fe 2 O 3 /NiFe 2 O 4 outer shells increase the energy density and reversible capacity due to a synergistically interactive effect.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）