APPLIED ORGANOMETALLIC CHEMISTRY
·
2020
·Vol. 34
·期 8
·e5722
·
IF 3.14
Jiadong Wang,Fakhre Alam,Qiqi Chang,Yanhui Chen,Tao Jiang
The methylene spacers and an uncoordinated diphenylphosphine moiety in the scaffold of the CH 3 Si(CH 2 ) n (PPh 2 ) 3 and Si(CH 2 PPh 2 ) 4 -type silylated diphosphine Ni(II) complex systems have a marked impact on their catalytic performance in selective ethylene dimerization. Ni(II)-based precatalyst 1 , bearing two methylene spacers in its framework, exhibited the highest catalytic activity of 1.29 × 10 8 g (mol Ni ) -1 h -1 , while precatalyst 3 , with three methylene spacers, affords the highest product selectivity (88%) toward the C 4 fraction. Crystallographic investigations revealed that the precatalyst 3 adopts the mononuclear bidentate binding mode and the steric constraints of its uncoordinated diphenylphosphine moiety may successfully tailor the catalytic environment of the catalyst. The precatalyst 4 may form a dinuclear complex and exhibits high catalytic activity by changing the ligand/Ni molar ratio. The high C 4 selectivity of precatalyst 3 has been rationalized by density functional theory (DFT) calculations and found to be consistent with the experimental results. The study also revealed that designing new systems of Ni(II)-based complexes and their systematic modifications may further provide potential and industrially viable catalyst systems for selective ethylene oligomerization.
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高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2019
·
IF 1.795
Yong Zhang,Han-xin Mei,Hai-li Gao,Qing-yuan Huo,Xiao-dong Jia,Yang Cao,Shi-wen Wang,Ji Yan,He-wei Luo,Jing Yang,Ai-qin Zhang,Ke-zheng Gao
(NH 4 )(Ni,Co)PO 4 ·0.67H 2 O (NNCP) was successfully synthesized by a simple one-step low-temperature hydrothermal method , and modified by metal oxides CuO , MnO 2 and Co 3 O 4 , so that the composites with different length scales and different energy storage mechanisms could be synergistically integrated. The electrochemical behaviors of NNCP, NNCP/CuO, NNCP/MnO 2 and NNCP/Co 3 O 4 as supercapacitor electrode materials in 3 mol·L −1 KOH electrolyte were studied by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS), and the morphology and structure of the synthesized materials were studied by SEM, XRD and Raman spectrum . Compared with other samples, the optimized NNCP/MnO 2 composites have higher specific capacitance and remarkable rate capability due to the micron flower-like rich interface structure , which provides a more active sites for electrochemical reaction , a shorter transport path for electrolyte ions, and the synergistic effect of NNCP and MnO 2 . The specific capacitances of NNCP/MnO 2 at current densities of 1, 4, 7 and 10 A g −1 are 3626, 3336, 3140 and 3104 F g −1 , respectively. These excellent properties confirm that the composite material has broad application prospects in the field of supercapacitor materials .
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高影响因子
Reaction Chemistry & Engineering
·
2020
·Vol. 5
·期 5
·886-895
·
IF 3.441
Xing-Gang Si,Yun-Peng Zhao,Qing-Lu Song,Jing-Pei Cao,Rui-Yu Wang,Xian-Yong Wei
A highly efficient Ni/N–C catalyst was synthesized by facile pyrolysis of a Ni-containing metal–organic framework (Ni-MOF), and its catalytic hydrogenolysis performance towards C–O bonds in lignin was evaluated in detail using diphenyl ether (DPE) as a model compound. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses show that the flower-like nanosheets of the Ni-MOF shrink, forming a loose and ordered spherical structure during pyrolysis. Under the optimal conditions, DPE was completely converted and the selectivity to monomers (benzene, cyclohexanol and cyclohexane) reached 99.1%. During the catalytic hydrogenolysis conversion (CHC) of DPE, the direct cleavage of the Caromatic–O bond affording benzene and phenol is the major reaction pathway, and a low H2 pressure is crucial to increase the monomer selectivity. Furthermore, Ni/N–C-450 shows high hydrogenolysis activity for other lignin-derived aryl ethers, such as benzyl phenyl ether, dibenzyl ether, dinaphthalene ether, benzyl 2-naphthyl ether and 3-methoxyphenol.
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 112
·111539-111548
·
IF 3.289
Hui Deng,Shi-Xi Zhao,Xia Wu,Lei Wei,Yu-Feng Deng,Ce-Wen Nan
The chief drawback of Li2MnSiO4 cathode materials is structural instability deriving from the transformation of [MnO4] tetrahedra to [MnO6] octahedra during oxidation from Mn(II) to Mn(III) and the Jahn–Teller effect especially from Mn(III) to Mn(IV). Based on the theory that Ni2+ could keep the [NiO4] ligand unchanged and stable during oxidation/reduction, [NiO4] tetrahedra may behave as a regional structural framework to support the total crystal lattice and alleviate structural distortion partially. In this paper we synthesize nano-Li2Mn1−xNixSiO4/C samples with a small amount of Ni as the dopant via a hydrothermal route. Firstly, we discuss the existential state of Ni through XPS spectra, and demonstrate that both Ni2+ and metallic Ni coexist, especially Ni2+ could improve structural stability. The influence of Ni doping on morphology, structural stability, and electrochemical performance is discussed through Raman spectroscopy and electrochemical tests below. It is confirmed that there exists an optimal Ni content under which the optimal performance is displayed. In our work, the optimum Ni content is 5.0%, and the maximal discharge capacity achieved is 235 mA h g−1 for the 5.0% Ni doped sample in the first cycle.
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高影响因子
CARBON
·
2021
·
IF 9.594
Xiao Zhang,Ping Yang,San Ping Jiang
The effect of transition metal particle size and distribution on the catalytic performances of carbon nanotubes (CNTs)-based catalysts has been attracting considerable attention in recent years. In this paper, Ni nanoparticles with a Ni 3 C shell structure were embedded in N-doped CNTs by thermal condensation of dicyandiamide with Ni salts followed by MoS 2 nanosheets deposition. Most interesting, dissolution, redistribution and diffusion of the embedded Ni/Ni 3 C nanoparticles take place during the stage of deposition of MoS 2 nanosheets on the CNTs with the help of excess S precursors. The dissolution, redistribution and diffusion result in the disappearance of Ni nanoparticles and formation of much finer Ni nanoclusters , which significantly facilitates the deposition and formation of vertical MoS 2 nanosheets on CNTs. The homogeneous distribution of Ni nanocluster leads to improved intrinsic conductivity and increased active sites. N-doped CNTs with optimized Ni and MoS 2 loading revealed high activity and stability for electrocatalytic hydrogen evolution reaction (HER). The as-prepared MoNiCNTs electrocatalysts exhibit superior HER activity with low onset potential and small Tafel slope value in both acidic and alkaline electrolyte conditions. The result provides a new platform for rational design and fabrication of high-performance non-precious transition metal based HER electrocatalysts.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Hui Wang,Hao Zhu,Yuelan Zhang,Jianglong Pu
A series of CTAB-templated Ni/Ce catalysts were synthesized by adding CTAB during the hydrothermal synthesis of ceria to improve the pore structure of catalysts. Their catalytic performance was evaluated in the steam reforming of acetic acid and the effects of CTAB concentration on the porous structures , reducibilities , morphology, and activity of catalysts were studied. The catalysts were characterized by BET, XRD , H 2 -TPR, XPS , HRTEM , in-situ DRIFTS , DTG , FTIR , and temperature-programmed reaction to elucidate the structure-activity relationship of the catalyst. The results showed that owing to the CTAB assistance, a high surface area of ceria could be achieved, which induced a better Ni dispersion with a smaller Ni size, strengthened the interaction between Ni and CeO 2 , and promoted the reducibility of Ni, obtaining higher activity and lower methane yield than Ni/Ce. Among these prepared samples, Ni/Ce–C6 showed the highest surface area and the best catalytic performance with a hydrogen yield of up to 82.5% even at a low temperature (550 °C). Owing to the stronger Ni-ceria interaction of Ni/Ce–C6, the lattice oxygen in ceria migrates easily to the Ni surface , interacts with the reaction intermediates, and thus improves the CO 2 /CO ratio in the products. Much more CO and CO 2 and less CH 4 were observed over Ni/Ce–C6 during the temperature-programmed reaction, indicating its high activity. In-situ DRFITS characterization demonstrated that the two types of catalysts had similar reaction intermediates but various adsorption and conversion abilities toward the acetic acid. More reaction intermediates were adsorbed at low temperatures and a higher conversion was obtained over Ni/Ce–C6 owing to its better Ni dispersion. The CTAB assistance inhibited the formation of amorphous carbon but facilitated the formation of graphitic carbon at ∼637 °C which did not induce catalyst deactivation .
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Kuangfu Huang,Ruohao Dong,Chao Wang,Wen Li,Hongxia Sun,Baoyou Geng
Design and synthesis of highly efficient, stable, and low-cost catalysts have a crucial role in the study of electrolytic water. In this work, a novel Fe–Ni layered double hydroxide (LDH) material with homogeneous heterostructures is successfully synthesized by a two-step hydrothermal method. Compared with the ordinary Fe–Ni LDH arrays prepared by one step, this structure has a rougher surface, so it has a more extensive active area, thus providing more active sites. Due to the synergistic effect of different elements and more exposure of active sites, the catalytic effect of this material for water splitting is outstanding. The post-optimized FeNi@FeNi electrode exhibits extraordinary OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) performance with OER overpotentials of 193, 231, and 306 mV and HER overpotentials of 127, 173, and 253 mV when the current density is 10, 20, and 50 mA·cm–2, respectively. The improved electrolytic water performance reveals that the design of homogeneous heterostructures is maybe an alternative route to exploit high-efficiency catalysts and promote the application of nonprecious metal catalytic materials.
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高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2021
·Vol. 26
·期 2
·481-490
·
IF 2.647
Jiang Li-Li,Zeng Min,Wang Chao-Yang,Luo Zhi-Hui,Li Hai-Yang,Yi Yong
Carbon-supported platinum-nickel alloy catalysts have become one of the main choices of proton exchange membrane fuel cells (PEMFCs) due to the high catalytic activity toward oxygen reduction reaction (ORR). In this work, carbon aerogel supported platinum-nickel solid solution alloy catalysts (Pt 3 Ni/CA) with small particles (~ 3.5 nm) and uniform distribution were prepared via a simple one-step rapid reduction method during which no structure guide or stabilizer is added. In rotating disk electrode (RDE), the mass activity (MA, 0.25 A mg Pt −1 ) and specific activity (SA, 4.69 A m −2 ) of the optimized Pt 3 Ni/CA catalysts for ORR are nearly 3.8 times and 6.5 times that of the state-of-the-art commercial carbon-supported platinum catalysts (Pt/C, 0.07 A mg Pt −1 and 0.72 A m −2 ), respectively. After the accelerated durability test (ADT), the as-prepared Pt 3 Ni/CA catalysts still keep a satisfactory MA and SA which are more than 3.4 and 8.9 times as high as that of Pt/C. The Koutecký-Levich (K-L) equation shows that the electrochemical reaction conforms to be a 4e − process.
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高影响因子
Journal of Nanostructure in Chemistry
·
2022
·Vol. 13
·期 6
·577-589
·
IF 8
Tian Ruonan,Gao Zeyuan,Lang Ruifeng,Li Na,Gu Huilin,Chen Gang,Guan Hongtao,Comini Elisabetta,Dong Chengjun
Lately novel strategies to enhance the sensing properties on iron oxide have been proposed to achieve high performance gas sensors for acetone detection. In this working report, the synthesis of iron-glycerate (Fe-Gly) using glycerol to combine with Fe 3+ is first presented. Depending on the thermal treatment, this compound can evolve into γ-Fe 2 O 3 , α/γ-Fe 2 O 3 and α-Fe 2 O 3 . α/γ-Fe 2 O 3 shows better sensing performance as far as acetone detection is concerned. Using the dual phases of α/γ-Fe 2 O 3 as a fundamental building block, their sensing properties were further improved using Ni doping and Ru nanoparticles functionalization. The high response and selectivity to acetone detection was ascribed to the synergistic effects of unique nanosheets, mixed phases, rich oxygen vacancies and excellent catalytic activity of Ru nanoparticles. Graphical abstract
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Fengdong Qu,Wenan Shang,Dongting Wang,Shiyu Du,Tiju Thomas,Shengping Ruan,Minghui Yang
Multishell, stable, porous metal-oxide microspheres (Ni–Co oxides, Co3O4 and NiO) have been synthesized through the amorphous coordination polymer-based self-templated method. Both oxides of Ni and Co show poor selectivity to xylene, but the composite phase has substantial selectivity (e.g., Sxylene/Sethanol = 2.69) and remarkable sensitivity (11.5–5 ppm xylene at 255 °C). The short response and recovery times (6 and 9 s), excellent humidity-resistance performance (with coefficient of variation = 11.4%), good cyclability, and long-term stability (sensitivity attenuation of ∼9.5% after 30 days and stable sensitivity thereafter) all show that this composite is a competitive solution to the problem of xylene sensing. The sensing performances are evidently due to the high specific surface area and the nano-heterostructure in the composite phase.
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PubMed
高影响因子
ELECTROCHEMISTRY
·
2021
·Vol. 89
·期 5
·461-466
·
IF 1.381
Zunzhi WANG,Shengxian SHE,Mengyao LV,Xujun YUAN,Hui SUN,Jun ZHAO,Jian YU,Xufeng YAN
The properties exhibited by Ni-rich cathode materials were enhanced through the mixed coating layers of Li3PO4 and boric acid. The scanning electron microscopy (SEM), the transmission electron microscope (TEM), the differential scanning calorimetry (DSC), the Electrochemical Impedance Spectroscopy (EIS), as well as the half-cell and full-cell charge-discharge tests were adopted for characterizing the structure and electrochemical properties exhibited by the cathode materials. As revealed by results, the Li3PO4 and boric mixed coating layers can effectively reduce the surface area and protect the direct contact between cathode material particle surface and electrolyte, meanwhile improving the structural stability and cycle performance. The coating of fast ionic conductor contributes to enhance the specific capacity possessed by the Ni-rich cathode materials accordingly.
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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2014
·Vol. 161
·期 6
·H375
·
IF 2.859
Zhuoyuan Yang,Yuqing Miao,Tianrui Wang,Xiaocai Liang,Mingshu Xiao,Weiwei Li,Yang Yang
The Ni ultrathin layer was obtained by the simple self-adsorption of Ni2+ on the surface of glassy carbon electrode. Through a consecutive potential scan in alkali solution, the adsorbed Ni2+ was transformed to the ultrathin layer of Ni(OH)2/NiOOH which exhibits good electrocatalysis toward the oxidation of glucose. Only a little of Ni2+ was consumed to obtain such an ultrathin layer of Ni with excellent electrochemical performance. Due to the low diffusion hindrance and the good electrocatalytic property of Ni(OH)2/NiOOH ultrathin structure, the electrode response toward glucose reaches a steady-state level within only 4 s, demonstrating a rapid and sensitive response. The calibration plot is linear over the wide concentration range of 0∼7 mM with a slope of 1.01 μA/mM (sensitivity) and a correlation coefficient of 0.9996. The detection limit of the electrode was found to be 10.9 μM at a signal-to-noise ratio of 3. The adsorption method is very simple and the ultrathin layer of Ni was formed in a controllable manner with the size lower than nanoscale, which will find the potential applications in nanofabrication for the nanodevices of fuel cell or electrochemical sensor in the future.
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高影响因子
危险品化学品经营许可证（带存储）