Catalysts
·
2019
·Vol. 9
·期 11
·944
·
IF 3.444
Jun Zhou,Yue Zhang,Song Li,Jing Chen
Heterogeneous catalysis often involves charge transfer between adsorbed molecules and the surface of catalyst, and thus their activity depends on the surface charge density. The efficiency of charge transfer could be optimized by adjusting the concentration of oxygen vacancies (Ov). In this work, hexagonal Ni(OH)2nanoparticles were initially synthesized by a hydrothermal process using aluminum powder as the sacrificial agent, and were then converted into 2D Ni/NiO nanocomposites through in situ reduction in hydrogen flow. The oxygen vacancy concentration in the NiO nanosheet could be well-controlled by adjusting the reduction temperature. This resulted in strikingly high activities for hydrogenation of nitrophenol. The Ni/NiO nanocomposite could easily be recovered by a magnetic field for reuse. The present finding is beneficial for producing better hydrogenation catalysts and paves the way for the design of highly efficient catalysts.Keywords:metal-oxide interaction;oxygen vacancy;hydrogenation;catalyst
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Shoujuan Lai,Chunxiao Lv,Shuai Chen,Ping Lu,Xilin She,Li Wan,Hongwei Wang,Jin Sun,Dongjiang Yang,Xiaoliang Zhao
Transition metal phosphides (TMPs) have been regarded as an alternative to Pt-based catalysts for hydrogen evolution reaction (HER) on account of their high performance and low cost. The ultrathin two-dimensional (2D) nanosheets of TMPs can expose abundant active sites and facilitate the transfer of mass/charge to enhance HER performance. However, the synthesis of ultrathin 2D nanosheets of TMPs is still a great challenge. Herein, we reported a novel and scalable strategy to prepare 2D ultrathin nickel phosphide nanosheets (∼2.5 nm) by using alginate as precursor through ice-templating process. The role of ice-templating is that the growth of the ice crystals would squeeze Ni-alginate into 2D nanosheets, and then forming Ni-alginate aerogels . The three-dimensional (3D) interconnected porous network of aerogels was advantageous to reduce the lattice strains of subsequent oxidation and phosphorization process. It is the key step to prepare 2D ultrathin nickel phosphides (Ni 2 P and Ni 5 P 4 ) nanosheets. As expected, all the prepared Ni 5 P 4 nanosheet aerogels displayed remarkable HER performance in 1 M KOH electrolyte. Especially, due to their ultrathin 2D nanosheets and high P percentage, the Ni 5 P 4 -500-350 sample with excellent long-term stability exhibits a low overpotential of 147 mV at current density of 10 mA cm −2 and a low Tafel slope of 57 mV dec −1 .
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FUEL
·
2022
·
IF 8.035
Han-Bing Gao,Le-Le Qiu,Fa-Peng Wu,Jian Xiao,Yun-Peng Zhao,Jing Liang,Yong-Hui Bai,Fang-Jing Liu,Jing-Pei Cao
Catalytic hydrogenolysis of C O bonds in lignin provides a promising route to produce high value-added biofuels and chemicals. However, designing highly active and stable catalysts for this process is still a challenge. Herein, a series of Ni/Al 2 O 3 catalysts were synthesized by calcination and reduction of layered double hydroxide precursors, and their activities were evaluated in the catalytic conversion of lignin-derived compounds. Diphenyl ether was completely converted with a 100% monomeric selectivity (cyclohexane and cyclohexanol) over the optimized Ni/Al 2 O 3 -500 under the optimal conditions of 200 ℃, 0.5 MPa H 2 and 1.5 h, indicating the excellent catalytic activity in the cleavage of C O bonds of the catalyst. The excellent catalytic performances of Ni/Al 2 O 3 -500 were originated from its relatively large specific surface area, well-developed porosity, small crystallite size, high Ni 0 concentration and strong interaction between the active metal and support. The reusability experiments show that Ni/Al 2 O 3 -500 possesses a relatively high stability for six reuses. Moreover, various lignin model compounds can be completely converted to corresponding monomeric products over Ni/Al 2 O 3 -500, indicating the applicability of this ingenious catalyst. The application of the hydrotalcite-derived Ni-based catalysts with high activity and stability provides a promising approach for the efficient hydrogenolysis of lignin derivatives.
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Journal of Energy Storage
·
2026
·
IF 10.7
Jiatai Wang,Siyu Dong,Yan Wang,Chengting Du,Dongming Chen,Cairang Zhouxian,Meng Li,Zhifeng Yan,Xingyu Zhao,Mingzhi Xiang,Cheng Qing
Nickel-rich layered ternary cathode materials have attracted extensive attention due to the high specific capacity and excellent cost-effectiveness. However, severe issues including irreversible phase transitions and progressive lattice expansion are observed during cycling. These issues lead to rapid capacity fading and limited cycling lifespan, severely restricting their large-scale commercial application. In this study, high-valent tantalum (Ta 5+ ) was employed as a dopant to simultaneously enhance Li + diffusion kinetics and structural stability. The Ta 5+ -doped LiNi 0.9 Co 0.05 Mn 0.05 O 2 cathode material was successfully synthesized via a combination of uniform co-precipitation and high-temperature solid-state methods. The results demonstrate that Ta 5+ doping can effectively suppress irreversible phase transitions and lattice distortion during cycling, thus improving the reversible specific discharge capacity and capacity retention. Electrochemical measurements indicate that the 0.3%Ta-NCM exhibits the outstanding performance. The specific discharge capacity of 219.32 mAh/g is obtained for the 0.3%Ta-NCM at 0.1C, which is 24.83 mAh/g higher than that of the NCM (194.49 mAh/g). The 0.3%Ta-NCM delivers a capacity retention of 89.35% after 100 cycles at 0.2C, which is significantly higher than the 85.97% of the pristine NCM. The retention rate surpasses that of the pristine NCM (66.74%) by 23.52% after 100 cycles at 1C. This work provides a feasible modification strategy for the structural regulation and performance optimization of nickel-rich ternary cathode materials.
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Catalysts
·
2023
·Vol. 13
·期 12
·1474
·
IF 3.9
Yuhang Cai,Anping Yin,Jianxiang Zhang,Jiatai Wang,Xiaofei Qin,Yibo Yang,Gaolei Qin,Xiaodong Sun,Peng He,Yong Yang
This study focuses on the synthesis and evaluation of carbon−coated Ni−Fe alloy catalysts (NiFex@C, x = 0, 0.3, 0.7, 1.1) for the hydrogenation of cinnamaldehyde. The catalysts were characterized using Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Raman spectroscopy, and X-ray Photoelectron Spectroscopy (XPS). The introduction of Fe was found to increase the average particle size of the bimetallic catalysts compared to the monometallic Ni@C. Ni existed in both metallic and oxide states, while Fe exhibited multiple oxidation states in the bimetallic catalysts. The carbon layer, approximately 2–3 nm thick, was confirmed to envelop the alloy particles. The catalytic performance of carbon−coated Ni−Fe alloy catalysts indicated that the addition of Fe to Ni@C enhanced the selectivity towards hydrocinnamaldehyde (HCAL), with NiFe0.7@C showing the highest selectivity (~88.6%) but at a reduced conversion rate. The carbon layer played a pivotal role in the stability and reusability of the catalysts. NiFe0.7@C maintained consistent performance over multiple reaction cycles, while NiFe0.7NPs (without a carbon layer) exhibited significant deactivation. Both catalysts displayed strong magnetism, facilitating easy separation from the reaction mixture. This study sheds light on the significance of the carbon layer in bimetallic catalysts and provides valuable insights for designing efficient catalysts for hydrogenation processes.Keywords:cinnamaldehyde hydrogenation;bimetallic catalysts;carbon−coated nanoparticles;Ni−Fe alloy;catalyst reusability
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Runqian Yang,Rui Xiong,Kunpeng Wang,Yining Jiang,Qian Chen,Liping Ruan
The problem of microwave pollution becomes more serious with the widespread popularity of electronic equipment; the development of microwave absorption materials has assumed critical importance. However, most reported carbon-based microwave absorption materials have no obvious absorption performance in 2–4 GHz (S band), which seriously limits their application. In this work, Ni(OH)2-coated peach pit carbon [Ni(OH)2/C1] is prepared by simple precipitation to achieve a minimum reflection loss (RL) value of −46.2 dB (5.6 mm, at 2.9 GHz) and absorption band cover 2.54–4 GHz in the thickness range of 3.7–6 mm in the S-band. In addition, Ni(OH)2/C1 achieved an RLmin value of −58.05 dB (2.7 mm, at 7.68 GHz) and maximum effective absorption bandwidth (EAB) of 3.95 GHz in the range 2–18 GHz. Our work provides new insights into the microwave absorption in low frequencies and expands the application range and scenarios of carbon-based materials.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2023
·
IF 6.2
Ling-Xin Kong,Yi Fang,Meng-Meng Wang,Hui-Hao Li,Shan Huang,Ji-Sen Li,Qi Xiao
Industrial-scale hydrogen energy deployment requires the design of highly efficient catalysts with low overpotential and excellent stability, particularly at high current densities. We report a novel method for fabricating an N-doped carbon coated self-supporting Ni-NiWO 4 heterojunction on a nickel foam (NF) catalyst (Ni-NiWO 4 @NC/NF) using a facile combination of hydrothermal and chemical vapor deposition techniques. The Ni-NiWO 4 @NC's plentiful catalytic active sites and their seamless contact with NF, along with the synergistic coupling of N-doped carbon, contribute to a decrease in charge transfer resistance and an improvement in catalyst stability. Impressively, when evaluated as an electrocatalyst in alkaline media, the overpotentials of Ni-NiWO 4 @NC/NF at a current density of 100 mA·cm −2 are only 125.6 mV for hydrogen evolution reaction (HER), and 308.8 mV for oxygen evolution reaction (OER), respectively. The catalyst also demonstrates exceptional stability for HER, OER, and water splitting at high current densities. In addition, the two-electrode electrolyzer using Ni-NiWO 4 @NC/NF as both cathode and anode need a cell voltage of 1.72 V to deliver 100 mA·cm −2 . These findings offer valuable insights into the design and advancement of self-supported non-noble transition metal electrocatalysts for large-scale hydrogen production in industrial applications.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Ruo-Ding Mao,Xing Zhang,Yi-Lei Li,Mu Lan,Wen-Ning Ren,Sheng-Jiang Huang,Xin Chang,Bing-Jie Wang,Yan Jiao,Le-Zhong Li,Xiao-Hui Wu
A solid-phase synthesis method was utilized to create a range of ferrite samples, specifically Sr 1- x Dy x Fe 12- x Ni x O 19 , where x values varied (0, 0.01, 0.02, 0.03, and 0.05). Through X-ray diffraction (XRD) analysis, it was found that up to x ≤ 0.03, the XRD pattern showed no discernible impurity phases. However, at x = 0.05, an observable impurity peak attributed to α-Fe 2 O 3 emerged. Room temperature hysteresis loop measurements revealed consistent hard magnetic behavior across all samples. Notably, changes in coercive force directly correlated with magnetocrystalline anisotropy. As substitution increased, the initial saturation magnetization ( M S ) of 59.68 emu/g (at x = 0.00) moderately reduced to 57.79 emu/g (at x = 0.05), representing a modest decline of 3.17 %. A clear trend was observed: decreasing grain size led to diminishing dielectric constants. Moreover, a strong link between the Nyquist diagram's semicircle diameter and sample resistivity was evident, showing distinctive metal-semiconductor behavior. These findings shed light on the structural and magnetic characteristics of Dy and Ni co-substituted SrFe 12 O 19 ferrites, suggesting potential for enhanced performance in advanced magnetic and electronic devices. This study significantly contributes to the field of ferrite materials, deepening our insights and paving the way for innovative applications in diverse technological domains.
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INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2023
·Vol. 24
·期 19
·14859
·
IF 5.6
Yan Xiao,Jie Li,Yuan Tan,Xingkun Chen,Fenghua Bai,Wenhao Luo,Yunjie Ding
Catalytic conversion of biomass-derived ethanol into n-butanol through Guerbet coupling reaction has become one of the key reactions in biomass valorization, thus attracting significant attention recently. Herein, a series of supported Cu catalysts derived from Ni-based hydrotalcite (HT) were prepared and performed in the continuous catalytic conversion of ethanol into butanol. Among the prepared catalysts, Cu/NiAlOxshows the best performance in terms of butanol selectivity and catalyst stability, with a sustained ethanol conversion of ~35% and butanol selectivity of 25% in a time-on-stream (TOS) of 110 h at 280 °C. While for the Cu/NiFeOxand Cu/NiCoOx, obvious catalyst deactivation and/or low butanol selectivity were obtained. Extensive characterization studies of the fresh and spent catalysts, i.e., X-ray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Hydrogen temperature-programmed reduction (H2-TPR), reveal that the catalysts’ deactivation is mainly caused by the support deconstruction during catalysis, which is highly dependent on the reducibility. Additionally, an appropriate acid–base property is pivotal for enhancing the product selectivity, which is beneficial for the key process of aldol-condensation to produce butanol.Keywords:Ni-based hydrotalcite;biomass conversion;support effect;selectivity;stability
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PubMed
高影响因子
FUEL
·
2023
·
IF 7.4
Deshi Yang,Jianpeng Huang,Zhipeng Hu,Yuanyuan Miao,Fengqiang Wang,Zhijun Zhang,Yanjun Xie,Shouxin Liu,Qingwen Wang,Charles U. Pittman
Lignin is the most abundant aromatic biopolymer. Thus, preparation of BTX (benzene, toluene and xylenes) by catalytic fast pyrolysis (CFP) of lignin is attractive. Ni-Al mixed metal oxide (MMO) catalysts, derived from pyrolyzing Ni-Al layered double hydroxides (LDH), were prepared for the catalytic fast pyrolysis of lignin. The effects of catalyst Ni/Al ratio, catalyst dosage and pyrolysis temperature on the liquid products were investigated by Py-GC/MS. The Ni 3 Al 3 -MMO produced the best liquid product distribution from lignin at 700 ℃. The selectivity of Ni 3 Al 3 -MMO for aliphatic hydrocarbons and monocyclic aromatic hydrocarbons (MAHs) was 18.0% and 78.2%, respectively. The selectivity to polyaromatic hydrocarbons (PAHs) was 3.8%. No phenols and phenolic derivatives were produced. This is related to the mesoporous catalytic structure (pore size of 14.37 nm), large external surface area (134.74 m 2 /g) and strong acidity (4.92 mmol NH3 /g) of Ni 3 Al 3 -MMO. In addition, a mechanistic study was performed with the lignin model compound (guaiacol) showing that Ni 3 Al 3 -MMO exhibits strong deoxygenation activity for aromatic C–O bond cleavage of lignin.
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ChemSusChem
·
2023
·
IF 8.4
Pu Zhang,Haihua Zeng,Decai Wen,Xiaoyu Sui,Zhuan Wang,Ying Wang,Hailong Chen,Yuxiang Weng,Jinlin Long
Graphical With the combination of surface organometallic chemistry and post-synthetic ligand exchange or calcination, the coordination environments of Ni sites were precisely manipulated to achieve a splendid improvement in hydrogen evolution reaction (HER) under visible-light irradiation. Thereinto, the 2,2′-bipyridine bonded Ni catalyst showed the optimum HER ability, 260 folds as Ni without ligand and 2.5 folds as 2-phenylpyridine bonded Ni catalyst. Solar hydrogen production at a high efficiency holds the significant importance in the age of energy crisis, while the micro-environment manipulation of active sites on photocatalysts plays a profound role in enhancing the catalytic performance. In this work, a series of well-defined single-site Ni-grafted TiO 2 photocatalysts with unique and specific coordination environments, 2,2′-bipyridine-Ni−O−TiO 2 (T−Ni Bpy) and 2-Phenylpyridine-Ni−O−TiO 2 (T−Ni Phpy), were constructed with the methods of surface organometallic chemistry combined with surface ligand exchange for visible-light-induced photocatalytic hydrogen evolution reaction (HER). A prominent rate of 33.82 μmol ⋅ g −1 ⋅ h −1 and a turnover frequency of 0.451 h −1 for Ni are achieved over the optimal catalyst T−Ni Bpy for HER, 260-fold higher than those of Ni−O−TiO 2 . Fewer electrons trapped oxygen vacancies and a larger portion of long-lived photogenerated electrons (>3 ns, ~52.9 %), which were demonstrated by the electron paramagnetic resonance and femtosecond transient IR absorption, correspond to the photocatalytic HER activity over the T−Ni Bpy. The number of long-lived free electrons injected from the Ni photoabsorber to the conduction band of TiO 2 is one of the determining factors for achieving the excellent HER activity.
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高影响因子
Analytical Methods
·
2016
·Vol. 9
·期 1
·163-169
·
IF 1.915
Qinglin Sheng,Yu Shen,Jian Zhang,Jianbin Zheng
In this work, attractive core–shell structured nanomaterials consisting of Ni doped Ag@C were synthesized. Further, a hydrogen peroxide (H2O2) sensor was fabricated by modifying the Ni doped Ag@C (Ni/Ag@C) nanocomposites onto the surface of a glassy carbon electrode (GCE). The composition and morphology of the Ni/Ag@C nanocomposites were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The results indicated that the nanocomposites were synthesized successfully and showed similar grain sizes and favorable dispersity. The electrochemical and electrocatalytic properties of the Ni/Ag@C nanocomposites were studied by cyclic voltammetry. An electrochemical investigation showed that the Ni/Ag@C nanocomposite modified GCE exhibited a good electrocatalytic ability for H2O2 reduction and it was used for the determination of H2O2. The linear range for H2O2 determination was from 0.03 mM to 17.0 mM with a detection limit of 0.01 mM (S/N = 3). The sensitivity was 22.94 μA mM−1 cm−2. It is expected that the application of the Ni/Ag@C nanocomposites could be extended to the construction of other sensors and applications in various sensing fields.
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