KINETICS AND CATALYSIS
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2018
·Vol. 58
·期 6
·800-808
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IF 0.926
Tang Chengli,Liping Lv,Zhang Limei,Tan Luxi,Dong Lichun
Ni@CeO 2 core–shell catalysts were synthesized via a facile surfactant-assisted hydrothermal method and their catalytic performance in the dry reforming of methane (DRM) reaction was evaluated. A variety of techniques including XRD, N 2 adsorption–desorption, SEM, TEM, TPO, TGA were employed to characterize the prepared or spent catalysts. The encapsulation by the CeO 2 shell, on one side, can restrict the sintering and growth of Ni nanoparticles under harsh reaction conditions. On the other side, compared to the conventional shell material of SiO 2 , CeO 2 can provide more lattice oxygens and vacancies, which is helpful to suppress coke deposition. Consequently, the Ni@CeO 2 core–shell catalysts exhibited better catalytic activity and stability in the DRM reaction with respect to the referenced Ni@SiO 2 core–shell catalysts and Ni/CeO 2 supported catalysts.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Zimo Lou,Jiasheng Zhou,Mei Sun,Jiang Xu,Kunlun Yang,Dan Lv,Yaping Zhao,Xinhua Xu
A Pd/MnO 2 /Ni foam electrode with hierarchical structure was synthesized via electrodeposition for efficient electrocatalytic hydrodechlorination. Compared with the ordinary Pd/Ni foam electrode, the introduction of MnO 2 greatly enhanced the catalytic reactivity and reduced the dose of precious metal Pd. Only a quarter of Pd was required for the Pd/MnO 2 /Ni foam compared to the Pd/Ni electrode to achieve complete dechlorination of 2,4-dichlorobenzoic acid (2,4-DCBA) within 120 min. Various characterizations suggested that MnO 2 covered the surface of the Ni foam and increased the specific surface area of the electrode, while Pd nanoparticles were subsequently deposited on MnO 2 . The atomic H ∗ -based indirect dechlorination was the dominant pathway while only approximately 13% of 2,4-DCBA was removed by direct electron transfer. Atomic H ∗ adsorbed on Pd acted as the key active species for the dechlorination of 2,4-DCBA by the Pd/MnO 2 /Ni foam electrode in this study. The introduction of MnO 2 would promote the water dissociation and the hydrogen evolution reaction, and provide Pd with more atomic H ∗ . Pd/MnO 2 /Ni foam exhibited good stability and reusability according to the XPS spectra and consecutive electrocatalytic experiments, which suggested its long-term potential for efficient removal of chlorinated contaminants. This work demonstrated a new strategy to design efficient electrocatalysts with less precious metal.
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高影响因子
GREEN CHEMISTRY
·
2018
·Vol. 20
·期 15
·3634-3642
·
IF 8.586
Bin Zhang,Bin Chen,Mark Douthwaite,Qiang Liu,Chao Zhang,Qifan Wu,Ruhui Shi,Peixuan Wu,Fengyu Zhao,Graham Hutchings
Carbon based materials are some of the most commonly studied catalysts for the conversion of cellulose to polyols. The catalytic performance of these materials, however, is typically limited by the access of the substrate to the active sites, which is governed by the poor solubility of cellulose in aqueous solutions. In an attempt to resolve this, we presented a novel hierarchical carbon material which was synthesized by a dual-templating method. Transmission electron microscopy and porosity measurements confirmed that the resultant materials consisted of both spherical macropores and well-defined mesoporous channels. Additional characterisation of this material revealed that it has an exceptionally high surface area (>1110 m2 g−1) and a high concentration of acidic sites, which are considered to be crucial for the hydrolysis of cellulose. Ni nanoparticles were subsequently immobilised onto this material and some additional carbon supports. It was determined that the high surface area and porosity of the synthesised carbon material assisted with the dispersion of the Ni nanoparticles. This Ni catalyst was found to be highly efficient for the one-pot conversion of cellulose to polyols, which is proposed to be a consequence of both the high number of acid sites and excellent Ni dispersion. This approach to catalyst design, offers a novel method for the valorisation of cellulose.
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CATALYSIS SURVEYS FROM ASIA
·
2018
·Vol. 22
·期 3
·129-135
·
IF 3.081
Zhang Di,Zhao Yun-Peng,Fan Xing,Liu Zhong-Qiu,Wang Rui-Yu,Wei Xian-Yong
A series of Ni/HZSM-5 catalysts with different Ni-loadings and Si/Al ratios were prepared by incipient wetness impregnation and employed for catalytic hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL). Their physicochemical properties were characterized by X-ray diffraction, nitrogen adsorption–desorption, X-ray photoelectron spectrometer, temperature-programmed desorption of ammonia,transmission electron microscopy, temperature-programmed reduction of hydrogen, and pyridine-adsorbed infrared spectroscopy. The diffraction peaks assigned to Ni phase were not observed, implying that nickel particles were small and had a high dispersion on the supports. The catalysts with a strong acidity and the appropriate ratio of Brönsted (B) acid sites to Lewis (L) acid sites (B/L = 4.9) show an excellent activity and selectivity for the hydrogenation of LA to GVL. High conversion of LA and selectivity towards GVL were achieved over 5 wt% Ni/HZSM-5-50. The maximum GVL yield of 100% over 5 wt% Ni/HZSM-5-50 was obtained under the optimized reaction conditions of 210 °C, 2 h, and 3 MPa initial hydrogen pressure.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Baosong Li,Xiao Li,Yuxing Huan,Wenzhe Xia,Weiwei Zhang
Influences of alumina nanoparticles on the microstructure and properties of Ni-B nanocomposite coating prepared by electro-co-deposition were studied. The effects of Al 2 O 3 nanoparticles, current density and electrodeposition time on microstructure, corrosion resistance , hardness and surface electronic state of Ni-B nanocomposite coating were revealed by SEM, EDX , XRD , XPS and electrochemical methods. The results demonstrate that the inclusion of Al 2 O 3 nanoparticles in Ni-B coating could improve the hardness and wear resistance accompanied with the grain refinement of the composite matrix . The incorporation of Al 2 O 3 nanoparticles alters the crystal orientation and then the microstructure of the Ni-B matrix. This enhances the corrosion resistance of Ni-B/Al 2 O 3 which is attributed to the compact structure and the reduction in the active surface area. XPS spectra indicate that the coating contains Ni, B, Al, N, O, and C. Under the influence of the grain refinement, hardening of the nanoparticles and the reduction in the active surface area, Ni-B/Al 2 O 3 composite coating exhibits excellent corrosion resistance and hardness.
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Journal of Energy Chemistry
·
2017
·
IF 2.594
Jinwei Sun,Yujiang Wang,Haikui Zou,Xiaoguang Guo,Zhou-jun Wang
Nanosheet (S) and nanoplate (P) γ-Al 2 O 3 were synthesized by simple hydrothermal methods and employed as supports for Ni catalysts in CO 2 methanation . Both of the nanostructured Ni/Al 2 O 3 catalysts displayed good activity. In comparison, the Ni/Al 2 O 3 -S catalyst showed higher CO 2 conversion than the Ni/Al 2 O 3 -P counterpart at the reaction temperature ranging from 250 to 400 °C. The physical and chemical properties of the catalysts were systematically characterized by N 2 sorption , X-ray diffraction (XRD), high resolution-transmission electron microscopy (HR-TEM), hydrogen temperature-programmed reduction (H 2 -TPR) and CO 2 temperature-programmed desorption (CO 2 -TPD) techniques. Higher specific surface area and stronger metal-support interactions were confirmed on the Ni/Al 2 O 3 -S catalyst, which may lead to smaller particle size of Ni nanoparticles . Moreover, the Ni/Al 2 O 3 -S catalyst possessed more abundant weak and medium basic sites, which would benefit the activation of CO 2 . The smaller Ni size and more suitable basic sites may rationalize the superior activity of the Ni/Al 2 O 3 -S catalyst. Besides, the Ni/Al 2 O 3 -S catalyst exhibited excellent stability at 325 °C for 40 h.
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COMPOSITES COMMUNICATIONS
·
2024
·
IF 6.5
Qixiong Zhang,Yafei Hou,Qi Yang,Jing Cuan,Weiping Li
High energy storage in multilayer composites is pivotal for the progress of advanced electronic and power device systems, however, the uneven distribution of electric fields caused by significant dielectric contrast between adjacent layers limits its potential gaining in energy density. Through incorporating transition layers into multilayer composites to mitigate interlayer dielectric contrast, herein, four-layer matrix gradient-structured composites ( x vol% PMMA/(100- x ) vol% P(VDF-HFP) have been designed and fabricated. The results demonstrate that the transition layers play a crucial role in hindering the breakdown process and homogenizing the electric field distribution. In addition, the linear PMMA as well as horizontally oriented nanoplates are also beneficial in enhancing their energy storage performances. The gradient-structured composite ultimately achieved an energy density of 24.3 J/cm³ and a charge-discharge efficiency of 86.6 % at 676.8 MV/m, significantly surpassing that of traditional multilayer nanocomposites. The strategies proposed here may represent a universal approach to further enhance energy storage performances of multilayer composites.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Bingyuan Dai,Minxuan Wang,Hui Xu,Hongbing Zheng,Yongzheng Zhang,Cheng Ma,Jitong Wang,Wenming Qiao,Licheng Ling
The precise atomic-scale preparation of single-atomic active sites with unique coordination structures in electrocatalysts for the carbon dioxide reduction reaction (CO 2 RR), coupled with the elucidation of their mechanisms at the atomic level, remains a formidable challenge. In this manuscript, a simple one-pot synthesis method was adopted to successfully synthesize an O-doped Ni single-atom catalyst (Ni-NOG), characterized by a distinct Ni-N 2 O 2 symmetric coordination structure. The incorporation of Ni-O bonds alters the electronic configuration of the catalyst’s central atoms within the catalyst, thereby boosting both the catalytic selectivity and efficiency during CO 2 RR. The synthesized electrocatalyst exhibited outstanding performance in the CO 2 RR process, achieving a Faraday efficiency (FE) of 97.4 % at a potential of −0.8315 V versus to reversible hydrogen electrode (vs. RHE). Furthermore, the selectivity remained consistently above 95 % throughout a 98-hour stability test, surpassing the performance of most advanced catalysts currently available. Theoretical simulations demonstrate that the Ni-N 2 O 2 symmetric coordination structure shows a small activation barrier in the rate-limiting step, favoring the swift generation of intermediate species and demonstrating robust catalytic activity. This work not only offers a straightforward and approach method for the preparation of single-atom catalysts but also clarifies the pivotal role of O-element doping within the coordination environment in enhancing catalyst performance.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Guan-Yu Pan,Yu-Long Ma,Xiao-Xia Ma,Yong-Gang Sun,Jun-Min Lv,Jian-Li Zhang
Ni–W/MCM-41 as a non-noble metal catalyst for catalytic conversion of corn stalk pretreated with alkali into polyol was prepared by an impregnation method. The results showed that pretreatment corn stalk with alkali removed 41.79 wt% of hemicellulose and 60.21 wt% of lignin and thereby increased the content of cellulose from 41.13 wt% to 59.29 wt%. Data obtained from X-ray photoelectron spectra exhibited that there was an intense interaction between nickel and tungsten. Meanwhile, the Ni 17 W 3 alloy was evidenced by X-ray diffraction spectra. These were very beneficial to enhance the catalytic conversion of lignocellulose into polyol. The maximum yield of 71.37 wt% polyol was obtained by catalytic hydrogenation of lignocellulose to ethylene glycol and 1,2-propylene glycol utilizing 5%Ni–15%W/MCM-41 catalyst under H 2 pressure of 6 MPa and 250 °C for 2 h.
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高影响因子
FUEL
·
2017
·
IF 4.601
Wei-Tu Li,Xian-Yong Wei,Xue-Ke Li,Xiang-Xue Liu,Zhan-Ku Li,Zhi-Min Zong
Catalysts Ni/γ-Al 2 O 3 , Mg 2 Si/γ-Al 2 O 3 , and Ni-Mg 2 Si/γ-Al 2 O 3 were prepared. Their activities for catalytic hydroconversions (CHCs) of some lignite-related model compounds were examined. For the CHCs of oxydibenzene (ODB), benzyloxybenzene, and oxybis(methylene)dibenzene, the suitable loadings of Ni and Mg 2 Si are 33 and 20% in Ni-Mg 2 Si/γ-Al 2 O 3 , respectively, and the optimal reaction conditions are 4 MPa of initial hydrogen pressure, 240 °C, and 2 h, under which ODB was almost completely converted to cyclohexane. The formation of possible intermediates during the CHC of ODB was discussed. Ni-Mg 2 Si/γ-Al 2 O 3 was proposed to have 3 functions, i.e., activating H 2 to biatomic active hydrogen (H⋯H), releasing H − , and heterolytically splitting H⋯H to release H − as well, resulting in the hydrogenation of aromatic rings and the hydrocracking of C O bonds, respectively.
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Nanoscale
·
2017
·Vol. 9
·期 17
·5583-5588
·
IF 7.367
Xueping Zhang,Liang Huang,Yujie Han,Miao Xu,Shaojun Dong
Developing efficient and earth-abundant oxygen evolution reaction (OER) electrocatalysts is of great importance in renewable energy research. Herein, we report nitrogen-doped carbon encapsulating γ-MoC/Ni heterostructures (γ-MoC/Ni@NC) for the first time as efficient OER electrocatalysts. The composites can be controlled by the addition of a Mo source to form a nanoparticle-assembled hierarchically porous nanostructure, which can enlarge the specific surface area, thus exposing more active sites. Moreover, we demonstrate that the formation of γ-MoC@Ni heterostructures and the resulting synergistic effect between γ-MoC and Ni can facilitate the reaction kinetics, leading to significantly improved OER activity with an onset overpotential of merely 240 mV, and a low overpotential of 310 mV to afford a current density of 10 mA cm−2. This work provides a new insight into the development of highly active and inexpensive OER electrocatalysts.
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PubMed
高影响因子
Journal of Physical Chemistry C
·
2017
·
IF 4.536
JianYi Chen,QiJian Niu,GuangKai Chen,Jun Nie,GuiPing Ma
This paper describes the preparation of Ni/Pt/CNFs via electrospinning technology, carbonization process, and chemical reduction method. The structure and composition of Ni/Pt/CNFs were characterized with X-ray diffraction, Raman spectroscopy, nitrogen adsorption isotherms, and X-ray photoelectron spectroscopy. Meanwhile, the morphology was analyzed with scanning electron microscopy and transmission electron microscopy. The electrochemical performance was evaluated by oxygen reduction reaction (ORR), cyclic voltammetry and chronopotentiometry. The results indicated that Pt and Ni nanoparticles were completely reduced in the experimental process and homogeneously distributed on the nanofibers with the average diameters of 3.8 and 17.8 nm, respectively. In addition, the Ni50/Pt/CNFs catalyst showed excellent electrocatalytic performance for ORR and superior specific and mass activities for methanol oxidation (the maximum current density is ca. 10.9 mA cm–2) and exhibited a slightly slower current decay over time, better than the reference samples which indicated a higher tolerance to CO-like intermediates.
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