Materials
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2018
·Vol. 11
·期 8
·1323
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IF 2.467
Yanlin Pan,Daoping Xiang,Ning Wang,Hui Li,Zhishuai Fan
Fine-grained W-6Ni-4Mn alloys were fabricated by spark plasma sintering (SPS) using mechanical milling W, Ni and Mn composite powders. The relative density of W-6Ni-4Mn alloy increases from 71.56% to 99.60% when it is sintered at a low temperature range of 1000–1200 °C for 3 min. The spark plasma sintering process of the alloy can be divided into three stages, which clarify the densification process of powder compacts. As the sintering temperature increases, the average W grain size increases but remains at less than 7 µm and the distribution of the binding phase is uniform. Transmission electron microscopy (TEM) observation reveals that the W-6Ni-4Mn alloy consists of the tungsten phase and the γ-(Ni, Mn, W) binding phase. As the sintering temperature increases, the Rockwell hardness and bending strength of alloys initially increases and then decreases. The optimum comprehensive hardness and bending strength of the alloy are obtained at 1150 °C. The main fracture mode of the alloys is W/W interface fracture.
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CHEMICAL ENGINEERING JOURNAL
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2022
·
IF 16.744
Fuzeyu Zhong,Xiaohu Ge,Weixiao Sun,Wei Du,Keng Sang,Chang Yao,Yueqiang Cao,Wenyao Chen,Gang Qian,Xuezhi Duan,Zhirong Yang,Xinggui Zhou,Jing Zhang
Total hydrogenation of hydroxymethylfurfural (HMF) (including hydrogenation of both furan ring and carbonyl group) produces 2,5-bis-(hydroxymethyl) tetrahydrofuran (BHTF), which can be used as rigid polymer monomer, green solvent, or precursor of high-value chemicals and has great market potential. Although Ni is regarded as the most selective metal for the total hydrogenation of HMF, Ni catalysts often suffer sintering and leaching under hydrothermal conditions. In this regard, development of hydrothermally stable Ni catalysts is highly desirable. Here, Ni on well mixed oxides (Ni/Mg a Al 10- a O x ) derived from layered double hydroxide (LDH) precursors was successfully synthesized via co-precipitation. The Ni/Mg a Al 10- a O x showed superior hydrothermal stability during the aqueous phase total hydrogenation of HMF, without noticeable activity loss, leaching and sintering after multiple reuse. In contrast, significant activity loss, leaching and sintering was observed for impregnated Ni counterparts. Catalyst characterization revealed the formation of highly dispersed Ni and well mixed porous oxides after the thermal reduction of the NiMgAl-LDH precursors as well as the stronger metal-support interactions of the NiMgAl-LDH as compared to impregnated Ni catalysts with similar Ni particle size. The markedly improved hydrothermal stability was due to enhanced metal support interactions derived from the LDH precursors, which prevents the undesired agglomeration and leaching of Ni in the hydrothermal environment. Moreover, a high BTHF yield of 99.0% was obtained using the Ni/Mg a Al 10- a O x under optimal reaction conditions. Density functional theory calculations suggest that the total hydrogenation of HMF over the Ni catalysts proceeds through the alkoxy pathway via “flat-lying” adsorption.
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Lubricants
·
2022
·Vol. 10
·期 12
·367
·
IF 3.584
Jiabei Wang,Hong Zhang,Wenjing Hu,Jiusheng Li
China’s rapid industrial development requires more energy consumption based on non-renewable energy resources. The energy consumption caused by unnecessary friction accounts for about 4.5% of the GDP in China. Although grease effectively lubricates machines, lubrication failure may occur under severe conditions. Nanomaterials exhibit intriguing tribological performances and have received much attention regarding lubrication. In this study, oleylamine-modified Ni nanoparticles (OA-Ni) were synthesized and used as lubricant additive in four kinds of commonly used greases: lithium, calcium, composite calcium, and polyurea grease. The OA-Ni were uniformly dispersed in the greases through electromagnetic stirring, ultrasonic vibration, and three-roll grinding. The physicochemical properties and the structure of OA-Ni-doped grease were investigated, while the feasibility of OA-Ni as various grease additives at different contact modes was evaluated by a four-ball friction tester and a UMT-tribolab tester. Tribological tests results revealed that the friction-reducing and anti-wear properties of point-to-point contact were increased by 56.7% and 70.3% in lithium grease, respectively, while those of the point-to-face contact were increased by 59.5% and 68.9% in polyurea grease, respectively. The present work provides not only theoretical guidance of nano nickel modification but also a practical reference for the application of modified nanomaterials to various greases.Keywords:nano-lubrication;modified nanomaterial;multiple greases;tribological properties
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Molecular Catalysis
·
2022
·
IF 5.089
Guangbo Xia,Zhiwei Zhou,Juan Qin,Binbin He,Yangyang Liu,Peiyong Sun,Wenliang Wu
In this paper, a modified facile one-pot AcHE method was adopted to prepare the nickel nanoparticles embedded into the tungsten and niobium metal oxides with binuclear acidities. Their physical and chemical properties were characterized by XRD, liquid N 2 sorption, Py-IR, NH 3 -TPD, Raman, H 2 -TPR, XPS and SEM-EDX and TEM techniques, and their catalytic performances were investigated in the hydrogenolysis of glycerol. The characterization results showed that both nickel nanoparticles can be uniformly doped into the Ni-Nb x W 10-x samples with ordered mesoporous structures and strong interaction between tungsten and niobium species would be formed resulting in the promotion of acidity amount and intensity. The 10 Ni-Nb 3 W 7 sample by synergistic effect has higher catalytic performance in the hydrogenolysis of glycerol than other samples owing to the larger acidities with appropriate ratio of Brønsted to Lewis acidity, whose 1, 3-PDO yield of 28.3% and the molar ratio of 1, 3-PDO to 1, 2-PDO of 2.13 would be obtained. The correlations between the ratio of Brønsted to Lewis acidity and the molar ratio of 1, 3-PDO to 1, 2-PDO and Brønsted acidity and 1, 3-PDO yield can be concluded as y = 2.608x-1.502 (R 2 =0.9831) and y = 1.035x-31.579 (R 2 =0.9730), respectively. Compared to the 10 Ni/Nb 3 W 7 sample prepared by impregnation method, the 10 Ni-Nb 3 W 7 sample shows good stability with slight decrease, where the glycerol conversion of 63.2% and 1,3-PDO selectivity of 42.1% can be obtained even though after repeated use for 6 times. The catalytic performance of 10 Ni-Nb 3 W 7 sample was also higher than other previously reported nickel-based catalysts, which can further prove a valuable reference for the preparation of effective catalysts in the glycerol hydrogenolysis with high selective production for 1, 3-PDO.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2022
·
IF 7.139
Yang Xu,Yingying Zhu,Pengfei Shen,Geng Chen,Xinbao Li
An improved method for hydrogen production by the steam reforming of phenol over novel fly ash-based catalysts is investigated. The Ni/Al 2 O 3 -ash catalysts are prepared by an equal-volume impregnation method and characterized by XRD , FESEM , BET and H 2 -TPR techniques. The effects of various process parameters including mixing ratio of fly ash, temperature, support, gas hourly space velocity (GHSV) and steam-to-carbon molar ratio (S/C) on the catalytic activity are investigated. The results show that fly ash mixing at 50 wt% and choosing γ-Al 2 O 3 as the support own the best performance. A maximum hydrogen yield of 83.8% is achieved at 450 °C with a S/C of 10 and a GHSV of 4968 h −1 with a maximum phenol conversion of 98.6%. The stability of the Ni-ash1-γA1 catalyst is further investigated and it is shown to continuously and stably react for more than 20 h at 450 °C with excellent catalytic reaction stability.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
·
IF 4.326
Wei Guo,Huanhao Chen
Nonthermal plasma (NTP)-assisted CO2 methanation can activate and convert stable CO2 molecules under ambient conditions as compared to conventional thermal catalysis (normal operation temperature up to 450 °C), which is a good technique to reduce CO2 emissions and simultaneously utilize the renewable energies like solar and wind. It is critical to develop a robust catalyst with good catalytic performance in order to make NTP catalytic CO2 methanation more competitive. Herein, we present a simple yet efficient synthesis of CeO2-supported Ni catalysts with yttrium (Y) as the promoter (i.e., Ni–Y/CeO2) via mechanochemical synthesis for efficient NTP catalytic CO2 methanation. The developed 7.5Ni–1Y/CeO2 catalyst demonstrated the highest energy efficiency values for CO2 conversion and CH4 yield, i.e., ∼57 gCO2 kWh–1 and ∼17 gCH4 kWh–1, respectively. The CO2-TPD and HRTEM results confirmed that the doped Y positively enhanced the basicity of the catalysts and also decreased the particle size of Ni nanoparticles, thus promoting the NTP catalytic activity of CO2 methanation. The catalyst displayed excellent short-term stability for plasma catalytic CO2 methanation over a 12 h on-stream evaluation, showing a CO2 conversion of 84.2 ± 1.8% and a CH4 selectivity of 83.3 ± 1.9%.
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JOURNAL OF SOLID STATE CHEMISTRY
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2022
·
IF 3.656
Jia-Wei Wang,Ying-Xia Ma,Xiao-Ya Kang,Hai-Jun Yang,Bing-Lu Liu,Shu-Shu Li,Xiao-Dan Zhang,Fen Ran
Metal-organic framework (MOF) has great potential in the field of supercapacitors as electrode material due to its high specific surface area and unique structure. Herein, a series of nickel MOFs (Ni-MOFs) were fabricated by one-pot solvothermal method at different experimental conditions. The electrochemical properties of the Ni-MOFs as electrode materials can be tuned by adjusting the experimental conditions to regulate the structures. The result indicates that a novel moss-like three-dimensional (3D) Ni-MOF had the maximum specific capacity of 638 C g -1 at a current density of 0.5 A g -1 . The asymmetric supercapacitor (ASC) assembled by using moss-like 3D Ni-MOF as the positive electrode and active carbon as the negative electrode exhibited a high energy density of 30.4 Wh kg -1 at power density of 407.4 W kg -1 .
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LANGMUIR
·
2022
·
IF 4.331
Junjie Si,Shuai Zhang,Xiuming Liu,Kuanjun Fang
Reactive dyes are widely used in textile industry, but their excessive use has caused several water pollution problems. In order to reasonably treat printing and dyeing wastewater, the highly efficient adsorbent for reactive dyes employed in this study is a new type metal–organic framework (MOF) material. Ni/Co MOF (NCM) was synthesized using the solvothermal method; then, the materials were analyzed by a series of characterization methods. This study mainly investigated the adsorption properties of NCM toward reactive dyes, and the adsorption capacities of NCM toward reactive red 218 were up to 200 mg·g–1. The results were found to conform to the Langmuir isotherm model, and the pseudo-second-order kinetic model by performing kinetic and isotherm studies on the adsorption process of reactive red 218 on NCM. The results of the intraparticle diffusion model suggest that the binding of reactive red 218 to NCM was mainly divided into three steps: adsorption, diffusion, and saturation. Moreover, it was concluded by thermodynamic fitting of the adsorption process that the adsorption of reactive red 218 by NCM proceeded spontaneously and was accompanied by an endothermic reaction, in which the adsorption of both occurred mainly by electrostatic attraction. The NCM has good reusability and still has good adsorption performance after being reused 5 times. Therefore, NCM is a very promising and excellent adsorbent for the treatment of dye wastewater because of its high efficiency and reusability.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Qingyu Wang,Xiaorui Liu,Haozhi Wang,Yuanhao Shen,Zequan Zhao,Cheng Zhong,Wenbin Hu
Zn–Ni battery is prospective green energy storage device. However, Zn(OH) 4 2– , the dissolved product of ZnO in the electrolyte, redistributes during the cycle, leading to the shape changing of the anode. This issue severely limits the lifespan of zinc anodes. Despite the success in improving the electrochemical performances of zinc anode via adding Ti 4 O 7 additive, the important mechanism of such modified anode has not been well understood. In addition, the aluminothermic reduction is facile and energy-saving. But the application of Ti 4 O 7 synthesized by this method in Zn–Ni batteries has not been studied. Herein, Ti 4 O 7 synthesized by facile and rapid aluminothermic reduction was applied to alkaline zinc anode. In subsequent electrochemical tests, the discharge capacity and cyclic performance of the zinc-nickel battery was significantly improved by adding as-prepared Ti 4 O 7 particles. At a high discharge current of 2.5 A (34.54 mA cm −2 ), the anode modified by Ti 4 O 7 delivered higher discharge capacity of 364 mAh g −1 , in contrast to the 283 mAh g −1 of pristine anode. Even at ultra-high discharge current of 10 A (138.16 mA cm −2 ), the battery operated stably for 480 cycles. Besides, the mechanism of Ti 4 O 7 modifying anode was studied in-depth by a variety of characterizations and density functional theory (DFT) calculations. We discovered that Ti 4 O 7 simultaneously regulates the distribution of electrons on the anode and Zn(OH) 4 2– in the electrolyte, contributing to forming uniform zinc anode during cycling.
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JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Feng Lin,Yudan Zhong,Yulong Ma,Yonggang Sun,Xiuqin Men,Yingbo Zhu
Hydrodeoxygenation (HDO) of renewable lignin-derived biomass in aqueous-phase to produce high value-added products is of great significance. However, developing new catalysts with high activity and excellent stability in an aqueous phase faces considerable challenges. Rare earth doping can effectively regulate the water exchange rate constant (WERC) value of the catalyst and play an important role in promoting the hydrolysis of ether bonds. Therefore, in this paper the bimetallic supported catalyst Ni–La 2 O 3 /H-ZSM-5 doped with rare earth metal La 2 O 3 was prepared, and used to catalyze the conversion of the lignin model compound guaiacol to cyclohexanol in the aqueous phase. The conversion of guaiacol catalyzed by 10Ni–3La 2 O 3 /H-ZSM-5 reaches 100%, and the selectivity of the product cyclohexanol is 85%. A series of characterizations illustrate that the doping of La 2 O 3 causes the electron transfer between La 2 O 3 –Ni and changes the distribution of Ni, and a strong metal carrier interaction occurs between the bimetallic Ni–La 2 O 3 and H-ZSM-5. This can effectively promote the hydrolysis of the C–O ether bond in guaiacol and significantly improve the activity of the catalyst. The possible catalytic reaction mechanism of Ni–La 2 O 3 /H-ZSM-5 catalytic conversion of guaiacol was proposed.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
·
IF 9.965
Chen Liang,Keyu Wang,Fang Xu,Yixing Wang,Shiyi Li,Kai Qu,Linfeng Lei,Linzhou Zhuang,Zhi Xu
Rational design of low-cost and efficient electrocatalyst for the anodic oxygen evolution reaction (OER) to replace noble-metal-based catalysts is greatly desired for the large-scale application of water electrocatalysis. And compared with the conventional powdery catalysts, the freestanding electrode architecture is more attractive owing to the enhanced kinetics and stability. In this work, we report an electrospinning-carbonization-post oxidation strategy to develop the freestanding N -doped carbon nanofibers anchored with Ni/NiO nanoparticles (denoted as Ni/NiO-NCNFs) as efficient OER electrocatalyst. In the synthesized Ni/NiO-NCNFs, the conductive ultrathin carbon layer could promote electron transfer and thus improve the electrocatalytic activity. Meanwhile, the ratio between Ni and NiO could be regulated by tuning the oxidation duration, so as to optimize the adsorption energy of intermediates and improve the OER activity. The Ni/NiO-NCNFs prepared with the oxidation time of 3 h exhibit a promising OER activity and long-term operation durability in 0.1 M KOH solution, requiring an overpotential as small as 153 mV to achieve a current density of 10 mA cm −2 . Its overpotential is far lower than that of the reported OER catalysts. This work offers an efficient pathway to develop low-cost and highly active freestanding transitional metal-based OER electrocatalyst for potential renewable electrochemical energy conversion.
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ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Fan Liu,Yang Tang,Jiaming Zhao,Yu Bai,Jiucun Chen,Liangliang Tian,Syed Shoaib Ahmad Shah,Shu-juan Bao
The insufficient intrinsic activity and electrical conductivity of transition metal-based catalysts still inhibits their practical application. In this work, carbon-coated nano-Ni-armed Mo 2 N nanosheets (Ni@C-Mo 2 N) assembled on Ni Foam (NF) by using CDs-NH 2 as reaction inducing and welding reagent. In-depth experiments reveal that the functional groups of (CDs) play a decisive role in regulating the phase composition and hierarchical structure of the final hybrid material. As electrocatalysts for hydrogen evolution reaction (HER), the optimized hierarchical Ni@C-Mo 2 N/NF achieved a very low overpotential of 38 mV at 10 mA cm −2 and outstanding stability of over 60 h, which should from the synergistic interfacial effect among the Ni, Mo 2 N and graphitic carbon optimized the electronic structure of catalyst with enhanced active sites, and improved electrical conductivity. This work provides novel insights for constructing more hierarchical multicomponent materials with the help of variable functional groups of CDs for further electrochemical applications.
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