MATERIALS CHARACTERIZATION
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2022
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IF 4.537
Z. Sun,X.X. Zhu,H.Z. Chen,L.X. Zhang
To address the excessive formation of brittle compounds when brazing TiAl alloys, a TiZrHfCoNiCu high-entropy brazed filler was developed to realize the brazing of TiAl/Ti 2 AlNb couples. The TiAl/Ti 2 AlNb brazed joints can be divided into 4 zones, i.e., 2 diffusion zones at the TiAl/braze filler, Ti 2 AlNb/braze filler interfaces and 2 zones divided inside the brazed seam. α 2 + γ-TiAl were the main reaction products formed at the TiAl/braze filler interface and α 2 + Ti 0.5 Al 0.12 Nb 0.38 were the main reaction products at the Ti 2 AlNb/braze filler interface. Effects of brazing temperatures on the interfacial microstructure and mechanical properties of the TiAl/Ti 2 AlNb brazed joints were investigated. When brazing at 1100°C/15 min, the highest shear strength can reach 157 MPa (room temperature), and 123 MPa (650°C) respectively. The relationship between the microstructure and the corresponding mechanical response were discussed in detail. This research can offer new insights on developing desirable brazing filler when joining TiAl and TiAl based alloys.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Lei Zuo,Junfeng Wang,Deqing Mei,Derick Adu-Mensah,Yaping Gao
The amounts of methyl stearate (C18:0) and trans-methyl oleate (trans-C18:1) increase during the catalytic transfer hydrogenation (CTH) process of biodiesel. Although it could improve the oxidation stability of biodiesel, its low temperature performance would be worsened. As for it, ultrasonic was introduced in the CTH to control the generation of C18:0 and trans-C18:1. In this study, the ultrasonic-assisted CTH was performed using Raney-Ni as catalyst, isopropanol as hydrogen donor and water as solvent. The effect of operating parameters such as reaction temperature, stirring rate, catalyst dosage, isopropanol amount and water amount on hydrogenation process was investigated. It was revealed that the optimum reaction conditions were determined as reaction temperature 80 °C, stirring rate 600 rpm, catalyst dosage 10 wt%, isopropanol amount 32 g and water amount 100 g in the aspect of the iodine value of bioidesel and the yield of C18:0 and trans-C18:1. The process of the ultrasonic-assisted CTH for biodiesel could be well described by pseudo-first order kinetic model. The conversion rate constants from C18:2 to C18:1 ( k 1 ) and from C18:1 to C18:0 ( k 2 ) were 0.02649 min −1 and 0.00438 min −1 , respectively. Ultrasonic field effectively repressed the selectivity of trans-C18:1 and further decreased the iodine value of biodiesel. On the basis of the same iodine value, the yield of C18:0 and hydrogenation time reduced with ultrasonic. Overall, ultrasonic is an effective intensification method for the CTH of biodiesel in the aspect of product selectivity and reaction rate.
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高影响因子
Nanomaterials
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2022
·Vol. 12
·期 4
·640
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IF 5.719
Lin Bo,Fujin Li,Yangbo Hou,Min Zuo,Degang Zhao
Forming co-alloying solid solutions has long been considered as an effective strategy for improving thermoelectric performance. Herein, the dense Cu2−x(MnFeNi)xSe (x= 0–0.09) with intrinsically low thermal conductivity was prepared by a melting-ball milling-hot pressing process. The influences of nanostructure and compositional gradient on the microstructure and thermoelectric properties of Cu2Se were evaluated. It was found that the thermal conductivity decreased from 1.54 Wm−1K−1to 0.64 Wm−1K−1at 300 K via the phonon scattering mechanisms caused by atomic disorder and nano defects. The maximumzTvalue for the Cu1.91(MnFeNi)0.09Se sample was 1.08 at 750 K, which was about 27% higher than that of a pristine sample.Keywords:thermoelectric material;nanostructured;interfacial engineering;multi-scale scattering centers
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Yang Yu,Xiaoping Cai,Xinyang Jiao,Chengyi Xu,Jinan Niu,Peizhong Feng
Ni-Al-Cr intermetallic compounds are candidate at extreme environment due to their excellent oxidation resistance at high temperature, and the oxidation resistance of Ni-Al-Cr alloy system has been studied extensively. However, the research on oxidation resistance mechanism of porous Ni-Al-Cr intermetallic compounds is still not deep. In our work, porous Ni-Al-Cr intermetallic compounds were synthesized by thermal explosion, and the oxidation resistance of porous Ni-Al-Cr system was mainly investigated. The results indicate that Cr promotes the formation of highly protective continuous Al 2 O 3 layer, increasing the oxidation resistance at 900 °C of porous Ni-Al-Cr. After oxidation at 900 °C for 120 h, the minimum mass gain of Ni-Al-Cr products is only 6.96%.
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高影响因子
POWDER METALLURGY
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2022
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IF 2.228
Ying Zhang,Meng Xiao,Yi-min Zhou,Yi-fu Shen
The eutectic FeNiCoCrTi0.6Nb0.4 high-entropy alloy coating (HEAC) is annealed in Argon at 450°C, 850°C and 1050°C to investigate the thermal stability. The results show that annealed coatings are all composed of BCC solid solution and Laves phase with no production of new phases. The fine eutectic cells can be maintained at a higher temperature in that continuous intracellular coarsening does not occur until annealing at 1050°C. With the increase of annealing temperature, the microhardness and wear resistance of FeNiCoCrTi0.6Nb0.4 coating increase first and then decrease slightly. Especially, the microhardness of FeNiCoCrTi0.6Nb0.4 annealed at 1050°C is only 6.03% lower than that of unannealed one, and the wear rate is only 10.70% higher than that of unannealed one, which strongly indicates that eutectic FeNiCoCrTi0.6Nb0.4 HEAC has excellent thermal stability and can be well applied in high-temperature environments.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Wensen Liu,Hui Su,Jian Zhang,Lina Wang,Yahui Liu,Jie Liang,Zhaowu Zhu
The hydrometallurgical process for the recovery of nickel and cobalt requires a complex and expensive impurity removal process. Solvent extraction is widely used in industry for the separation, purification, and concentration of metals. However, current commercial extractants encounter some difficulties when cobalt and nickel are extracted from solutions containing a large amount of impurities such as manganese and calcium. There is an urgent need to develop new reagents for the selective extraction of Ni and Co. In this study, N-(2-ethylhexyl)-pyridine-4-carboxamide (NEHPCA) was synthesized, and the metal extraction capacity of its synergistic solvent extraction (SSX) system with dinonylnaphthalene sulfonic acid (DNNSA) and tributyl phosphate (TBP) modifier was examined. The experimental results show that the selectivity of the new SSX system has the order Cu > Ni > Co > Zn > Mn > Ca > Al ≈ Cr (III) ≈ Mg ≈ Fe (III), with excellent selectivity for nickel and cobalt. Using an organic phase composed of 0.7 M NEHPCA, 0.35 M DNNSA, and 0.2 M TBP under 1:1O/A operation, after three-stage theoretical extraction, more than 99% of nickel and cobalt can be recovered from a synthetic leaching solution of nickel laterite ore. Mechanistic studies showed that NEHPCA and water molecules participate in the internal coordination of metals, and DNNSA provided coordination anions to achieve charge balance, forming the Ni complex in this SSX system which existed most likely in the form of [Ni(NEHPCA) 2 (H 2 O) 4 ](DNNS) 2 in the organic phase.
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JOURNAL OF CATALYSIS
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2023
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IF 7.3
Ziliang Yuan,Guanghui Wang,Xun Li,Yurong He,Pan Wang,Francesco Mauriello,Zehui Zhang
Earth-abundant metal catalysts, especially Ni, are highly favourable in heterogeneous reactions compared with noble metal ones. Herein, Ni nanoparticle catalysts supported on Vulcan carbon (VCX) support were prepared through a simple impregnation-reduction method and utilized for the acceptorless dehydrogenation of primary amines to secondary amines. The best performance was achieved with Ni (A) /VXC with Ni particle size of 11.9 nm at 150 °C. Smaller or larger particle sizes resulted in a lower TOF, indicating a structure-sensitive activity. This work may serve as inspiration for further investigation into acceptorless dehydrogenation using non-noble metal catalysts.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2023
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IF 7.2
Lingxuan Meng,Lingye Zhang,Suyi Liu,Feng Wang,Huimin Wu
Pollution-free and low-cost bifunctional catalysts are important part for hydrogen production . In this paper, composite catalysts Ni 0.2 Mo 0.8 N/CeO 2 -x/NF (x = n(Ce)/n(Ni)- 0.1, 0.3, 0.5) were synthesized via hydrothermal and calcination methods on foam nickel (NF). Experimental results show that the composites have better properties than CeO 2 /NF, Ni 0.2 Mo 0.8 N/NF and MoN/CeO 2 /NF. The electrochemical properties of the composites depend on the ratio of nickel and cerium . A proper proportion of nickel leads to a larger specific surface area, increased electron capacity, more active sites, and better overall performance. Among the tested composites, Ni 0.2 Mo 0.8 N/CeO 2 -0.3/NF exhibits the best electrochemical performance and is well-suited for catalyzing the hydrogen evolution reaction (HER) and urea oxidation reaction (UOR). For HER, the potential is −120 mV @ 100 mA cm −2 . And for UOR, the UOR potential is only 1.462 V @ 100 mA cm −2 . A two-electrode electrolyzer of Ni 0.2 Mo 0.8 N/CeO 2 -0.3/NF|| Ni 0.2 Mo 0.8 N/CeO 2 -0.3/NF was also built. Overall urea splitting (OUS) is 1.672 V @ 100 mA cm −2 , which is 187 mV smaller than overall water splitting (OWS, 1.859 V). Therefore, Ni 0.2 Mo 0.8 N/CeO 2 has potential application in hydrogen production from urea-rich wastewater electrolysis.
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高影响因子
FUEL
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2021
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IF 6.609
Ao Wang,Wei Xu,Yunjuan Sun,Kang Sun,Jianchun Jiang
High electrical conductivity and excellent pore affinity for electrolyte are the two necessary characteristics for high-rate performance supercapacitors based on activated carbon electrode. Nevertheless, it is fairly challenging to simultaneously improve them due to they are usually in the tug of war relationship in aqueous electrolyte. Herein, based on the different antioxidant abilities of graphitized carbon and amorphous carbon, a well-designed heterogeneous structure activated carbon (HGCAC) with graphitized carbon shell, amorphous carbon inner, and hydrophilic pores has been successfully prepared by a combined procedure of solid phase grinding, catalytic graphitization, and hydrothermal oxidation. Owing to the heterogeneous structure, HGCAC exhibits a joint improvement of electrical conductivity and the pore affinity for aqueous electrolyte, and thus leads to the remarkable enhancement of capacitance and rate capability, in comparison with the commercial coconut shell derived activated carbon (CAC) for supercapacitor. When the current density increases 100 times to 50 A g −1 , the specific capacitance of as-made HGCAC is 203.4 F g −1 , with the capacitance retention of 81.0%, being nearly 2.14 times of CAC’s capacitance (95.2 F g −1 ) and 1.6 times of its capacitance retention (51.0%). Moreover, good rate capability is still maintained when HGCAC is assembled to a coin type supercapacitor, with the capacitance retention of 82.1% at 50 A g −1 .
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
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2023
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IF 19
Xiao-Hui Wang,Rou Yuan,Shi-Bin Yin,Qing-Ling Hong,Quan-Guo Zhai,Yu-Cheng Jiang,Yu Chen,Shu-Ni Li
Nitrite (NO 2 − ) and hydrazine (N 2 H 4 ) are common N-pollutants in groundwater. The electrochemical method can realize the treatment of N-pollutants and the synthesis of energy substance ammonia (NH 3 ). Designing and synthesizing efficient electrocatalysts is of great significance. Herein, ultrathin Co 0.5 NiS nanosheets attached on nickel foam (Co 0.5 NiS-NSs/NF) are synthesized via cyanogel-NaBH 4 hydrolysis process and succedent sulfurization approach. Owing to the ultrathin nanosheet structure and the interaction between Ni and Co, Co 0.5 NiS-NSs/NF exhibits high activity for NO 2 − reduction reaction (NO 2 − RR), in which the Faraday efficiency is 92.2% and the NH 3 yield is 0.25 mmol h −1 cm −2 at −0.15 V potential. Meanwhile, Co 0.5 NiS-NSs/NF also displays remarkable activity for N 2 H 4 oxidation reaction in KOH electrolyte. Therefore, a symmetrical Co 0.5 NiS-NSs/NF||Co 0.5 NiS-NSs/NF electrolyzer is assembled, which only needs the operating voltage of 0.36 V to reach 10 mA cm −2 for NO 2 − -to-NH 3 conversion in the presence of N 2 H 4 . This work reports a promising and efficient strategy for NH 3 production at a small operating voltage and treatment of the N-pollutants.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2026
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IF 9.6
Bing Leng,Feng Gao,Yaozu Jia,Xianbo Yu,Mingyi Zhang,Hong Gao,Junpeng Xiao,Peng Yu,Jing Yao
Corrosion engineering constructs MoO 4 2− -intercalated NiFe-LDH electrocatalyst for stable and efficient seawater splitting. • MoO 4 2− intercalation enhances the M-O covalency. • The MoO 4 2− intercalation promotes the formation of high-valent Ni 3+ and Ni 4+ active species. • The hard Lewis acid MoO 4 2− has strong selectivity toward OH − , avoiding the competitiveness of Cl − in seawater. • The MoO 4 2− -intercalated NiFe-LDH electrocatalyst relies on the synergistic catalytic mechanism of AEM and LOM. Undesirable adverse reactions caused by chloride ions (Cl − ) and the corrosion of active sites are obstacles to the oxygen evolution reaction (OER) in seawater splitting. Herein, we design a molybdate anion (MoO 4 2− )-intercalated NiFe-layered double hydroxide (NiFe-LDH) electrocatalyst and demonstrate that the introduction of MoO 4 2− generates more abundant oxygen vacancies, enhances the M-O covalency, and accelerates the formation of nickel (III) ion (Ni 3+ ) and further oxidation to nickel (IV) ion (Ni 4+ ). Meanwhile, the hard Lewis acid MoO 4 2− exhibits strong selectivity toward OH − , avoiding the competitiveness and corrosiveness of Cl − in seawater. The intercalation of MoO 4 2− modulates the electronic structure of nickel (Ni) and iron (Fe) active sites, optimizing the adsorbate evolution mechanism (AEM) pathway. Simultaneously, moderate activation of lattice oxygen favors the lattice oxygen evolution mechanism (LOM) pathway, facilitating a delicate balance between the AEM and LOM. In a 1.0 M KOH + 0.5 M NaCl electrolyte, the catalyst shows an overpotential of only 224 mV at a current density of 50 mA cm −2 and can operate stably for 1500 h. This work provides a simple and effective method for preparing high-efficiency OER catalysts through corrosion strategies, which can be widely applied to seawater electrolysis. Molybdate anion(MoO 4 2− ) can inhibit the corrosive damage of chloride ions (Cl − ) on the surface of NiFe-LDH catalysts, inducing beneficial surface reconstruction of MoO 4 2− /NiFe-LDH to generate a large number of oxygen evolution active sites,significantly reducing the reaction overpotential, enabling the catalyst to exhibit ultra-long electrocatalytic durability exceeding 1500 h at a high current of 1000 mA cm −2 . Download: Download high-res image (277KB) Download: Download full-size image
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JOURNAL OF ALLOYS AND COMPOUNDS
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2023
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IF 6.2
Tiantian Liu,Xiaomei Yu,Shuang Yu,Huijing Yang,Qimeng Sun,Chengduo Wang,Songjie Li,Jin You Zheng
Alkaline water electrolysis techniques have enormous potential for industrial-scale hydrogen generation, but a lack of effective and low-cost bifunctional electrocatalysts capable of steady high-current density operation has hampered progress. Layered double hydroxides (LDHs) have been considered promising OER electrocatalysts, but their poor electrical conductivity impedes hydrogen evolution reaction (HER) activity. Integrating LDHs with transition metal phosphides (TMPs) can potentially achieve bifunctional capability by overcoming individual limitations. Herein, CoP@NiFe LDH/Ni heterostructured catalyst was rapidly synthesized by a scalable two-step electrodeposition method. The integration of NiFe LDH with CoP enhanced its electrical conductivity. Meanwhile, electron transfer occurred from the metal atoms to the more electronegative phosphorus, facilitating phosphorus to act as a proton acceptor and expedite the HER process. Benefiting from the synergistic integration and optimized electronic structure, CoP@NiFe LDH/Ni exhibited excellent alkaline water-splitting performances with low overpotentials of 260 mV for HER and 351 mV for OER at 400 mA/cm 2 . The CoP@NiFe LDH/Ni two-electrode-based alkaline electrolyzer displayed a cell voltage of 2.13 V and stable operation for 100 h at a high current density of 1000 mA/cm 2 . This work elucidates a strategy to tackle critical challenges impeding the design and preparation of high-current-density tolerant bifunctional electrocatalysts.
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