Nanomaterials
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2022
·Vol. 12
·期 13
·2287
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IF 5.719
Jiabei Wang,Hong Zhang,Wenjing Hu,Jiusheng Li
Nanomaterials exhibit intriguing tribological performance and have received particular attention in the lubrication field. However, little research has been found that surveyed the application of nanometer Ni in lithium grease. In this study, nanometer Ni with an average size of 100 nm was synthesized by the direct reduction method and dispersed in lithium grease. The feasibility of nanometer Ni as a grease additive in different lubrication scenarios was evaluated by a four-ball friction tester and a TE77 reciprocating friction tester. The lubrication mechanism was analyzed based on the evaluated physical properties of lithium grease and the characterization of the wear surface. The tribology test results showed the tribological properties of lithium grease were enhanced after introducing nanometer Ni. When the dosage was 0.2 wt%, the friction-reducing and anti-wear properties of point-to-point contact increased by 34.8% and 35.2%, respectively, while those of the point-to-flat contact increased by 28.8% and 38.7%, respectively. Our work not only provides theoretical guidance and practical reference for the utilization of nanometer Ni in grease, but also explains several possible lubrication mechanisms of nanomaterials in grease.Keywords:nano-lubrication;lithium grease;additives;nanometer Ni;tribological performance
研究领域:
材料科学
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机械工程
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产品关联
DOI
PubMed
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2022
·Vol. 30
·期 1
·54-62
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IF 3.85
Xu Nuo,Yuan Zirui,Ma Zhihong,Guo Xinli,Zhu Yunfeng,Zou Yongjin,Zhang Yao
MgH 2 with a large hydrogen capacity is regarded as a promising hydrogen storage material. However, it still suffers from high thermal stability and sluggish kinetics. In this paper, highly dispersed nano-Ni has been successfully prepared by using the polyol reduction method with an average size of 2.14 nm, which significantly improves the de/rehydrogenation properties of MgH 2 . The MgH 2 —10wt% nano-Ni sample starts releasing H 2 at 497 K, and roughly 6.2wt% H 2 has been liberated at 583 K. The rehydrogenation kinetics of the sample are also greatly improved, and the adsorption capacity reaches 5.3wt% H 2 in 1000 s at 482 K and under 3 MPa hydrogen pressure. Moreover, the activation energies of de/rehydrogenation of the MgH 2 —10wt% nano-Ni sample are reduced to (88 ± 2) and (87 ± 1) kJ·mol −1 , respectively. In addition, the thermal stability of the MgH 2 —10wt% nano-Ni system is reduced by 5.5 kJ per mol H 2 from that of pristine MgH 2 . This finding indicates that nano-Ni significantly improves both the thermodynamic and kinetic performances of the de/rehydrogenation of MgH 2 , serving as a bi-functional additive of both reagent and catalyst.
研究领域:
材料科学
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化学工程
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能源存储
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2023
·
IF 4.2
Zongpeng Zou,Tao Zhang,Li Lv,Wenxiang Tang,Guoquan Zhang,Raju Kumar Gupta,Yan Wang,Shengwei Tang
Dry reforming of methane (DRM) presents a sustainable approach to convert greenhouse gases CO2 and CH4 into syngas. However, the industrialization of DRM is hindered by the short catalyst lifespan due to carbon deposition. Carbon deposition on Ni-catalysts is attributed to Ni step edges, which serve as carbon nucleation centers. We propose an innovative strategy to prevent carbon nucleation by modulating Ni size to eliminate Ni step edges. Ni was loaded on MCM-41, SBA-15, and DFNS (dendritic fibrous nanosilica) to prepare three distinct Ni catalysts. By altering the precursor concentration using the proposed microemulsion antisolvent coprecipitation method, we successfully adjusted the Ni size on DFNS. Ni particles with a diameter of ∼5 nm were obtained on DFNS, exhibiting excellent Ni dispersion and a physical spacing effect due to the specific preparation method and porous structure. Carbon deposition rates on Ni/MCM-41 and Ni/SBA-15 were 30.23 mgc·gcat·–1·h–1 and 16.33 mgc·gcat·–1·h–1, respectively. Remarkably, the carbon deposition rate on Ni/DFNS was only 0.15 mgc·gcat·–1·h–1. The gasification rate of deposited C to CO on the 5 nm Ni particles loaded on Ni/DFNS was five times that of the polyhedral Ni particles of Ni/MCM-41. This was attributed to the elimination of Ni step edges, which weakened C adsorption strength and enhanced the reaction of deposited C with O* to form CO. Our proposed catalyst preparation strategy is based on designing the catalyst microstructure to eliminate carbon nucleation sites. This research provides guidance for designing or preparing Ni-based catalysts for DRM with reduced carbon deposition.
研究领域:
催化化学
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材料科学
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环境科学
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产品关联
DOI
高影响因子
ACS Applied Energy Materials
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2018
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IF 0
Zhongliang Ma,Jiguang Zhang,Yunfeng Zhu,Huaijun Lin,Yana Liu,Yao Zhang,Delong Zhu,Liquan Li
Metal nanocatalysis is an effective method to enhance the hydrogen storage properties of magnesium hydride (MgH2), and the catalytic effect can be further improved by a matrix material supported nanometal. In this work, carbon supported nano-Ni (Ni@C) was synthesized by calcination of dimethylglyoxime dinickel chelate, and then it was doped into MgH2 to improve the de/rehydrogenation kinetics. This shows that the homogeneously distributed Ni with refined particle size in carbon base leads to superior catalytic effects on hydrogen absorption/desorption of MgH2-5 wt % Ni@C. The MgH2-5 wt % Ni@C starts to desorb hydrogen at 187 °C, which is 113 °C lower than that of as-milled MgH2. Moreover, it takes only 500 s to thoroughly desorb hydrogen at 300 °C, which is 3000 s faster than as-milled MgH2 under the same dehydrogenation conditions. According to the Kissinger’s method, the apparent activation energy for desorption of the MgH2-5 wt % Ni@C is 66.5 ± 1.8 kJ mol–1, which is about 79.9 kJ mol–1 lower than that of as-milled MgH2. Cycling experiments show that the capacity retentions of hydrogen absorption and desorption after 10 cycles at 275 °C are 91% and 93%, respectively. Transmission electron microscope analysis shows that part of Ni transformed to Mg2NiH4/Mg2Ni during hydrogen absorption/desorption cycles.
研究领域:
材料科学
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化学工程
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产品关联
DOI
GREEN CHEMISTRY
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2017
·Vol. 19
·期 17
·4157-4168
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IF 9.125
Shiyou Xing,Pengmei Lv,Haoran Yuan,Lingmei Yang,Zhongming Wang,Zhenhong Yuan,Yong Chen
A new vision of using carbon dioxide (CO2) catalytic processing of oleic acid into C8–C15 alkanes over a nano-nickel/zeolite catalyst is reported in this paper. The inherent and essential reasons which make this achievable are clearly resolved by using totally new catalytic reaction pathways of oleic acid transformation in a CO2 atmosphere. The yield of C8–C15 ingredients reaches 73.10 mol% in a CO2 atmosphere, which is much higher than the 49.67 mol% yield obtained in a hydrogen (H2) atmosphere. In the absence of an external H2 source, products which are similar to aviation fuel are generated where aromatization of propene (C3H6) oxidative dehydrogenation (ODH) involving CO2 and propane (C3H8) and hydrogen transfer reactions are found to account for hydrogen liberation in oleic acid and achieve its re-arrangement in the final alkane products. The reaction pathway in the CO2 atmosphere is significantly different from that in the H2 atmosphere, as shown by the presence of 8-heptadecene, γ-stearolactone, and 3-heptadecene as reaction intermediates, as well as a CO formation pathway. Because of the highly dispersed Ni metal center on the zeolite support, H2 spillover is observed in the H2 atmosphere, which inhibits the production of short-chain alkanes and reveals the inherent disadvantage of using H2. The CO2 processing of oleic acid described in this paper will significantly contribute to future CO2 utilization chemistry and provide an economical and promising approach for the production of sustainable alkane products which are similar to aviation fuel.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
RSC Advances
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2021
·Vol. 11
·期 33
·20580-20590
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IF 3.361
Lingxing Zhang,Rui Zhang,Wenna Wang,Shuang Han,Pengfei Xiao
In this study, nano-nickel ferrite (NiFe2O4) was successfully prepared by hydrothermal synthesis and applied to the oxidative removal of chlortetracycline hydrochloride (CTH) in the presence of ultraviolet radiation (UV) and peroxymonosulfate (PMS). Several characterization methods were used to reveal the morphology and surface properties of nano-NiFe2O4, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared absorption (FTIR) spectroscopy. The removal efficiency of CTH, the factors affecting the reaction process and the reaction mechanism of PMS activated by UV combined with nano-NiFe2O4 (UV + nano-NiFe2O4/PMS) in aqueous solution were systematically studied. The results showed that the UV + nano-NiFe2O4/PMS system led to a higher removal efficiency of CTH than other parallel systems. The results also showed that the CTH removal efficiency was enhanced under optimal conditions ([nano-NiFe2O4] = 1 g L−1, [PMS] = 1 g L−1, [UV wavelength] = 254 nm and [pH] = 11) and that a removal efficiency of 96.98% could be achieved after 60 min. In addition, the influence of the PMS concentration, CTH concentration, dosage of added nano-NiFe2O4 and pH on the PMS activation efficiency and CTH oxidative degradation effect was studied. Inorganic anions such as Cl−, HCO3−, CO32− and NO3− increased the removal efficiency of CTH by 21.29%, 27.17%, 25.32% and 5.96% respectively, while H2PO4− inhibited CTH removal, and the removal efficiency of CTH decreased 6.08% after 60 min. Free radical identification tests detected SO4−˙, OH˙ and 1O2 and showed that these species participated in the degradation reaction of CTH. The results of LC-MS and TOC analysis showed that CTH was degraded in the UV + nano-NiFe2O4/PMS system through hydroxylation, demethylation, deamination, and dehydration reaction and finally mineralized into CO2. These findings confirmed that nano-NiFe2O4 is a green and efficient heterogeneous catalyst for activation of PMS and demonstrates potential applicability in the treatment of antibiotic wastewater.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Research and Technology-JMR&T
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2023
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IF 6.4
Jin Yun,Chiyu Zhou,Borui Guo,Fangping Wang,Yingjie Zhou,Zhonglei Ma,Jianbin Qin
With the development of highly integrated electronic equipment, electromagnetic pollution and heat congregation have become serious problems. Electromagnetic interference (EMI) shielding materials with high thermal conductivity and mechanical properties are highly desirable. Herein, the reduced graphene oxide/Ni nanowire aerogels (GNiA) were firstly prepared via hydrothermal reducing process and freeze-drying. Subsequently, using epoxy (EP) as a polymer matrix, the GNiA/EP composites with high compression strength of 147 MPa were fabricated by vacuum filtration and curing. The GNiA endows the composites with great electromagnetic wave loss, as well as improved phonon propagation efficiency, resulting in the super high EMI SE. With the GNiA content of 12.14 wt%, the EMI SE and thermal conductivity of GNiA/EP composites can reach as high as 85 dB and 1.69 W/(m·K) respectively. The obtained GNiA/EP composites provide a strategy to meet the demand for electronic equipment for new-generation EMI shielding materials.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
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2020
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IF 8.758
Xue Zhao,Ziqiong Yang,Artem V. Kuklin,Glib V. Baryshnikov,Hans Ågren,Wenjing Liu,Haibo Zhang,Xiaohai Zhou
The electricity provided by solar or wind power can drive nitrogen in the atmosphere, combining with ubiquitous water to form ammonia, and distributed production methods can alleviate the irreversible damage to the environment caused by the energy-intensive Haber–Bosch process. Here, we have designed a novel Ni-doped BCN heterojunction (S/M-BOPs-1) as a catalyst for the electrochemical nitrogen reduction reaction (NRR). The ammonia yield rate and Faraday efficiency in NRR driven by S/M-BOPs-1 reach up to 16.72 μg–1 h–1 cm–2 and 13.06%, respectively. Moreover, S/M-BOPs-1 still maintains high NRR activity and excellent stability after recycling for eight times and long-time operation of 12 h. Using density functional theory calculations, we reveal a possible NRR path for N2 to NH3 on Ni, BCN, and the S/M-BOPs-1 composite surfaces. The interaction between the BCN matrix and Ni nanoparticles promotes a synergetic effect for the electrochemical NRR efficiency due to the partial electron transfer from the Ni particles to BCN that inhibits hydrogen evolution reaction and decreases the rate-determining step on Ni surfaces toward NRR by ∼1.5 times. Therefore, efficient NRR performance can be achieved by tuning the electronic properties of non-noble metals via the formation of a heterointerface.
研究领域:
化学
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材料科学
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环境科学
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电化学
✓ 已验证
DOI
PubMed
高影响因子
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