JOURNAL OF CATALYSIS
·
2017
·
IF 6.844
Tingting Hou,Yehong Wang,Jian Zhang,Mingrun Li,Jianmin Lu,Marc Heggen,Carsten Sievers,Feng Wang
In many catalytic processes, metastable reaction intermediates are more valuable and desirable than final products. Here, we report Ni–Ni δ+ clusters on ceria where the extent of reduction of nickel oxide/ceria in H 2 has been optimized. This catalyst shows high selectivity in reducing nitrobenzene to azoxybenzene, the latter usually being metastable. Due to strong electronic metal–support interactions between Ni and ceria, mixed Ni–Ni δ+ clusters are formed on ceria even after reduction at 500 °C in hydrogen. The Ni–Ni δ+ clusters are highly dispersed on ceria, as observed by high-angle annular dark-field scanning–transmission electron microscopy and energy-dispersive X-ray spectroscopy element mapping. This structural uniqueness is clearly reflected in the inhibition of azoxybenzene hydrogenation to aniline, and therefore the catalyst shows high azoxybenzene selectivity (92%). In comparison, the Ni metal catalyst mostly gives aniline and the NiO catalyst has low activity. This study shows how to steer catalytic reactions toward metastable intermediate products by tuning the extent of reduction of metal oxides deposited on reducible oxides.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Nan Lyu,Jiaheng Wang,Hongjiang Shen,Zhiyong Bao,Yong Zhang,Yucheng Wu
Graphene quantum dots interfacial-decorated hierarchical Ni/PS core/shell nanocapsules were successfully synthesized by three-step liquid chemical method . The morphologies and electromagnetic properties were carefully studied in order to investigate the dielectric shells modulated tunable microwave absorption in 1–18 GHz (L–Ku), based on the anisotropic nanoflakes assembled magnetic core. With different GQDs/PS ratio in the shells, the dielectric attenuation can be flexibly tuned by the interfacial polarizations deriving from the density modulation of interfacial-decorated polar GQDs in the nonpolar insulative PS matrix. The calculated impedance matching maps, microwave absorption efficiencies ( R E ), reflection loss ( RL ) and simulations illustrated the coincident effect with an obvious rise-fall performance in X–Ku band. The tunable RL value in fixed frequency of X band and shifting absorption peaks from Ku to X band were achieved in different absorber thickness with the minimum RL below −42.5 dB and the effective absorption bandwidth ( RL < −10 dB) above 2.04 GHz.
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高影响因子
FUEL PROCESSING TECHNOLOGY
·
2021
·
IF 7.033
Enkang Fu,Yu Qiu,Huaichang Lu,Sijun Wang,Lishan Liu,Hanjun Feng,Yanxin Yang,Zizhan Wu,Yunlong Xie,Feng Gong,Rui Xiao
Ammonia (NH 3 ) has been regarded as an attractive energy source for hydrogen production via catalytic decomposition , especially over non-noble metal catalysts . Owing to the decent performance and low cost, nickel (Ni) based catalysts have been widely studied for catalytic decomposition of NH 3 where the decomposition rates, can be further tailored by adding other metals. Herein, we synthesized bimetallic M(M = Co, Fe, Cu)Ni/Al 2 O 3 catalysts delivering superior catalytic performance at a wide temperature range of 350–750 °C. Co-Ni/Al 2 O 3 demonstrated nearly 100% conversion of NH 3 decomposition to H 2 at 700 °C and the gas hourly space velocity of 30,000 ml g −1 min −1 , which was ~20.85% higher than that of intrinsic Ni/Al 2 O 3 . The structural characterizations indicated that Co could decrease the particle size and enhance the dispersion of active sites. The density functional theory calculations substantiated that the associative decomposition of N to generate N 2 was the rate-determining step of the NH 3 decomposition reactions . NH 3 Temperature Programmed Desorption (TPD) results suggested that the enhanced catalytic performance was predominantly attributed to the Co that decreases the energy barrier for the associative decomposition of N to form N 2 . This study provides new insights in designing diverse catalysts for efficient NH 3 decomposition for controllable H 2 production.
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Frontiers of Chemical Science and Engineering
·
2017
·Vol. 12
·期 1
·24-31
·
IF 1.712
Han Dongxu,Zhang Zhiguo,Bao Zongbi,Xing Huabin,Ren Qilong
We have successfully prepared a series of Pd-Ni/TiO 2 catalysts by a one-step impregnation-reduction method. Among these catalysts with different compositions of Ni and Pd, the one with the Ni:Pd ratio of 2.95 showed the best activity. Small monodispersed Pd-Ni bimetallic nanoparticles were loaded on the surface of titanium oxide nanopowder as confirmed with TEM and EDS mapping. The XPS analysis demonstrated that Pd exists as 31% Pd(II) species and 69% Pd(0) species and all nickel is Ni(II). The prepared Pd-Ni/TiO 2 exhibited enhanced catalytic activity compared to an equal amount of Pd/TiO 2 for Suzuki-Miyaura reactions together with excellent applicability and reusability.
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高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Jinming Li,Lei Zhang
3D pothole-rich hierarchical amorphous carbon network-encapsulated Ni nanoparticles (Ni NPs) electrocatalytic material (3D-Ni@AC) is successfully designed and synthesized via a facile in-situ NaCl template-removal method for electrochemical non-enzymatic cysteine (CySH) detection. 3D-Ni@AC assembled from the carbon nanosheet encapsulated Ni NPs layer-by-layer interlaced possesses interconnected porous network structure, the network structure of carbon nano-layer can effectively prevent the agglomeration of Ni NPs, ensuring full utilization of active materials. Cyclic voltammetric (CV) study showed that 3D-Ni@AC/GCE displayed high electrocatalytic activity toward the oxidation of CySH compared to template-free Ni@AC/GCE. The unique structure, the enlarged specific surface area and the synergistic effects from the excellent conductivity of carbon frame and Ni NPs provide fast electrons/ions transfer and favorable electrocatalytic activity for the electro-oxidation of CySH. In an electrolyte solution of 0.1 M NaOH, the constructed CySH sensor offered a high sensitivity (0.079 mA/cm 2 μM), a low detection limit (0.15 μM) and a wide linear range (from 0.8 to 85 μM). The fabricated high electrocatalytic performance sensor was utilized to monitor the CySH levels in urine and serum, and satisfactory results were gained. Moreover, 3D-Ni@AC electrode showed good reproducibility, stability, and anti-interference ability, indicating that 3D-Ni@AC can be used as a good electrocatalytic material in practical biological applications.
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CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Wenjuan Shen,Bingning Wang,Falong Jia,Zhihui Ai,Lizhi Zhang
In general, the final product of atrazine (ATR) degradation by reactive oxygen species is cyanuric acid bearing a stable s -triazine ring, which is not further oxidized under mild conditions. In this study, we demonstrate that the presence of Ni(II) can increase the aerobic ATR degradation rate of core–shell Fe@Fe 2 O 3 nanowires (CSFN) by 6 times and also achieve the cleavage of recalcitrant s -triazine ring. The cleavage of s -triazine ring in this novel system was confirmed by the measurements of formic acid and nitrite acid. On the basis of experimental results, a feasible mechanism was proposed to account for the promoted aerobic ATR degradation and the facile s -triazine ring cleavage as follows. First, Ni(II) adsorbed on the surface of CSFN was reduced to nickel metal, which favored the generation of active hydrogen (•H). The in-situ generated •H then reduced ATR to 4-ethylamino-6-isopropylamino-1,3,5-triazine intermediate of easy ring opening property, rather than the recalcitrant cyanuric acid. Finally, this ATR degradation pathway change promoted the aerobic ATR degradation and benefited the s -triazine ring cleavage. This study clarifies the importance of degradation pathway on the ring-opening of organic pollutants, and also provides a mild method to remove s -triazine herbicides with molecular oxygen and zero-valent iron.
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NANOTECHNOLOGY
·
2022
·Vol. 33
·期 35
·355401
·
IF 3.953
Qianqian Ding,Yuan Wang,Liang Ma
Transforming levulinic acid (LA) to γ-valerolactone (GVL) is a significant route for converting biomass into valuable chemicals. The development of an efficient and robust heterogeneous catalyst for this reaction has aroused great interest. In this work, nitrogen-doped graphene (NG) supported nickel (Ni) based heterogeneous catalyst with excellent activities was successfully synthesized. The Ni/NG catalyst shows outstanding performance for hydrogenation of LA to GVL at a relatively low temperature of 140 °C, which is superior to most of reported heterogeneous catalysts. Further investigations indicate Ni nanoparticles are the active sites and the NG also plays an indispensable role. The catalytic performance is highly depended on the crystallinity, particles sizes and electronic structure of Ni in Ni/NG catalyst, which can be optimized by nitrogen doping. This work affords a new route for designing robust and excellent heterogeneous catalysts by doping method to optimize the support.
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ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Ran Duan,Yejun Li,Shen Gong,Yonggang Tong,Zhou Li,Weihong Qi
The development of industrial application of water splitting demands simple and effective methods for the preparation of highly efficient electrocatalysts that are inexpensive and robust. Herein, we report a simple activation method to decorate 3D cobalt iron oxyhydroxide (CoFe-OOH) nanosheets on Co 2 P nanoparticles with Ni foams (NF) as substrates. The synthesized catalysts exhibit excellent activity for electrochemical oxygen evolution reaction due to the hierarchical heterostructures and synergistic effects of CoFe-OOH and Co 2 P. The as-prepared catalysts require a low overpotential of 199 mV to deliver 30 mA cm −2 in oxygen evolution reaction in 1 M KOH with a small Tafel slope of 39 mV dec −1 , indicating favorable kinetics during electrolysis. The synthesized catalysts are further used as cathode and anode for overall water splitting, which only requires a cell voltage of 1.60 V at a current density of 30 mA cm −2 . This work provides new insights on the preparation of efficient electrocatalysts for overall water splitting, which may have the potentials for industrial water electrolysis.
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Energies
·
2020
·Vol. 13
·期 4
·846
·
IF 2.702
Changzhou Chen,Peng Liu,Minghao Zhou,Brajendra K. Sharma,Jianchun Jiang
Transfer hydrogenation is a novel and efficient method to realize the hydrogenation in different chemical reactions and exploring a simple heterogeneous catalyst with high activity is crucial. Ni/CNT was synthesized through a traditional impregnation method, and the detailed physicochemical properties were performed by means of XRD, TEM, XPS, BET, and ICP analysis. Through the screening of loading amounts, solvents, reaction temperature, and reaction time, 20% Ni/CNT achieves an almost complete conversion of phenol after 60 min at 220 °C in the absence of external hydrogen. Furthermore, the catalytic system is carried out on a variety of phenol derivatives for the generation of corresponding cyclohexanols with good to excellent results. The mechanism suggests that the hydrogenation of phenol to cyclohexanone is the first step, while the hydrogenation of cyclohexanone for the generation of cyclohexanol takes place in a successive step. Moreover, Ni/CNT catalyst can be magnetically recovered and reused in the next test for succeeding four times.Keywords:phenol;hydrogenation;Ni/CNT;cyclohexanol;transfer hydrogenation
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JOURNAL OF ELECTRONIC MATERIALS
·
2016
·Vol. 45
·期 10
·5133-5139
·
IF 1.491
Ullah Atta,Liu Hanxing,Hao Hua,Iqbal Javed,Yao Zhonghua,Cao Minghe,Xu Qi
The ceramics were prepared using the solid-state reaction method and their phase, microstructure and microwave dielectric properties were investigated. A single-phase clinoenstatite system with monoclinic structure (space group P2 1 /c) was confirmed through x-ray diffraction (XRD) analysis for the compositions with x ≤ 0.1. The compositions with x ≥ 0.15 contain SiO 2 and (Mg 1− x
Ni
x
) 2 SiO 4 phases only as confirmed from the XRD data of their sintered samples. The unit cell volume was decreased while the theoretical density was increased with increase in x from 0 to 0.1. A decrease in dielectric constant ( ε
r ) while an increase in unloaded quality factor multiplying the resonant frequency ( Q
u
f
o ) and temperature coefficient of resonant frequency ( τ
f ) was observed with increase in Ni content from 0 to x = 0.1. In the present study, ε
r ∼ 6.10, Q
u
f
o ∼ 118,702 GHz and τ
f ∼ −10 ppm/°C was achieved for the composition with x = 0.1 sintered at 1425°C for 9 h. The material is a good candidate for millimeter wave applications.
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IONICS
·
2022
·Vol. 28
·期 12
·5571-5580
·
IF 2.961
Wu Meijuan,Wang Liwei,Xu Fugang,Ma Guangran
A Ni-MOF superstructure composed of 2D nanosheet (2D Ni-MOFss) was prepared and further combined with reduce graphene oxide (rGO) for electrochemical detection of acetaminophen (AP). The structure and properties of the 2D Ni-MOFss were characterized by SEM, XRD, XPS, and electrochemical method. The loosened 2D lamella structure endowed the 2D Ni-MOFss with improved electrocatalysis and low charge transfer resistance than bulky Ni-MOF. After integration with rGO, the composite 2D Ni-MOFss/rGO shows significantly enhanced catalysis for redox reaction of AP with high current response and low over-potential. An electrochemical sensor for AP based on the 2D Ni-MOFss/rGO shows a wide linear range of 0.036 to 50 μM, and a low detection limit of 0.012 μM. The sensor with high sensitivity, good selectivity, and stability also show satisfied recovery for detecting AP in real sample. The facile preparation and enhanced catalysis make these 2D MOF composite attractive materials for electrochemical sensors.
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高影响因子
LANGMUIR
·
2021
·
IF 3.882
Yang Wang,Yingying Wei,Qianrui Xu,Shimin Shao,Hong Man,Yingrui Nie,Zhifei Wang,Yong Jiang
Magnetic materials perform well in the purification of histidine-rich proteins (His-proteins). In this work, a facile fabrication of yolk–shell magnetic Fe3O4@NiSiO3/Ni microspheres for the efficient purification of His-proteins has been reported. Yolk–shell Fe3O4@NiSiO3 microspheres were prepared via hydrothermal reaction. Then Ni nanoparticles (NPs) were loaded on Fe3O4@NiSiO3 microspheres after the adsorption and in situ reduction of nickel acetylacetonate. The yolk–shell Fe3O4@NiSiO3/Ni microspheres had a hierarchical flower-like structure and large cavities. The size of the cavity depended on the reaction time. This indicated that the microspheres had a large specific surface area for loading of more Ni NPs, which was crucial to the high His-protein adsorption capacity of Fe3O4@NiSiO3/Ni microspheres. Fe3O4@NiSiO3/Ni microspheres had a high adsorption capacity for bovine hemoglobin (BHb, 2822 mg/g), which was better than the values of other His-protein adsorbents. Fe3O4@NiSiO3/Ni microspheres still had a high BHb separation efficiency after seven separation cycles, indicating its good reusability and stability. Therefore, the as-prepared bifunctional yolk–shell Fe3O4@NiSiO3/Ni microspheres exhibited great practical application value for His-protein purification.
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