JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Zhi Dong,Songhua Chen,Shaocun Liu,Zongqing Ma,Liming Yu
As a promising route to prepare ultrafine-grained or nanocrystalline materials, powder metallurgy has long been used to produce some metal materials with desirable microstructure. However, the challenges of rapid grain growth and torpid densification during this process always frustrate the endeavor. Especially, for the oxide dispersion strengthened (ODS) alloy, although grain growth is suppressed greatly by the traditional oxide addition, the densification of metal matrix is also hindered, especially at low temperature. To overcome such limitation, exploring a kind of oxide that can be used as both grain growth inhibitor and sintering accelerator for metal matrix will be significant. In this work, it is found that accelerated sintering can be achieved in Mo-ZrO 2 system at low temperature. The kinetic simulation results indicate that although the volume diffusion has been found to be the dominant sintering mechanism for Mo-ZrO 2 system, a significant contribution from grain boundary diffusion is also identified, which is the essential mechanism behind the accelerated sintering of this system at low temperature. Besides, the grain boundary migration also can be significantly restricted by the intergranular ZrO 2 particles. After sintering at only 1480 °C in the absence of external pressure assistance and subsequent hot forging , nanocrystalline microstructure with an average grain size of 480 nm can be obtained. The ZrO 2 second-phase particles are uniformly distributed at grain interior and grain boundaries, enhancing the recrystallization temperature and microstructural stability of metal matrix, which renders the prepared Mo-ZrO 2 alloy a stable high-strength performance characteristic even under high temperatures.
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高影响因子
Crystals
·
2022
·Vol. 12
·期 2
·190
·
IF 2.67
Lihong Jia,Wansen Ma,Qianyu Zhuang,Yani Zhang,Jie Dang
Metal ion modification is considered to be an effective way to construct metal oxides with specific physical and chemical properties. In this paper, we prepare a tungsten oxide (WO3) film co-modified by Co-ion and Mo-ion to serve as the electrochromic material through a one-step electrodeposition method. The effect of electrodeposition time on film thickness, surface morphology and electrochromic properties is systematically studied as well. The results show that, compared with pure WO3film, the surface morphology of the tungsten oxide film modified by Co-ion and Mo-ion (WO3: Co, Mo) is significantly different. The Co and Mo co-modified film possesses a higher transmission modulation (58.5% at 600 nm) and rapid switching speed (coloring and bleaching time are 2.7 s and 5.6 s, respectively), low impedance value and excellent cycle stability. The performance enhancement is mainly attributed to the coral-like structure of the membrane, which provides a larger specific surface area, more ion adsorption sites and faster ion diffusion. Therefore, this work provides a fast and low-cost method to prepare tungsten oxide electrochromic films co-modified with cobalt and molybdenum ions. At the same time, it also provides an idea to obtain films with different electrochromic properties by adjusting the film thickness.Keywords:electrochromic;metal ion modification;structure;WO3film
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高影响因子
BIOMASS & BIOENERGY
·
2022
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IF 5.774
Guojun Hao,Hongying Liu,Zhibing Chang,Kechen Song,Xin Yang,Han Ma,Wenjing Wang
In this work, lignin depolymerization was examined over CoMo sulfide catalysts supported on different carriers in supercritical ethanol system. The temperature, time, MoS 2 and carrier effects on the lignin depolymerization were investigated. 95.76% liquefaction yield with negligible char was achieved over Co–Mo–S/ZrO 2 at 340 °C for 150 min. The liquid product was mainly composed of C 4 –C 8 alcohols, C 4 –C 10 esters and C 7 –C 10 aromatic compounds . The synergistic effect of active sites and acid-base sites on support played an important role in lignin depolymerization. Furthermore, the Co–Mo–S/ZrO 2 catalyst is reusable with 8% loss in liquefaction yield after 5 cyclic runs. We believe that acid/base carriers or additives that can promote the medium to generate abundant free radicals or ions to replace external hydrogen pressure are one of the prospects for the design of depolymerization lignin catalysts.
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高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2023
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IF 3.6
Dongyang He,Hailang Liu,Zhuangzhi Wu,Dezhi Wang
The low ductility of refractory Mo-based materials limits their further processing and wide applications. To address this challenge, a composite strengthening and toughening strategy was proposed by the simultaneous addition of WC and La 2 O 3 . And a collaborative improvement of strength and ductility is achieved over the as-sintered Mo-WC-La 2 O 3 , exhibiting a total elongation (TE) of 33.63% and an ultimate tensile strength (UTS) of 611.33 MPa, about 50.27% and 24.76% larger than those of pure Mo, respectively. Furthermore, the corresponding microstructural features and tensile fracture behavior were also discussed to explore the improvement mechanism. And it is found that the enhancement should be attributed to the high relative density, grain refinement, generated substructures and secondary phase particle refinement. Moreover, the additional toughening mechanisms of crack deflection, particles pull-out and crack halt can also prevent crack extension, which helps to give full play to the potential ductility of Mo composites. This work provides a new pathway for manufacturing advanced Mo-based products with excellent strength-ductility balance.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 11
·14966-14975
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IF 2.478
Chen Tian-Yun,Zhang Ya-Qi,Fu Ying-Yan,Qian Min,Dai Hao-Jiang,Ye Bo,Qin Shan,Yang Qing-Hua
Hydrogen energy is regarded as one of the most important clean energy in the twenty-first century, and improving the catalytic efficiency of hydrogen evolution reaction (HER) is the basis for realizing the large-scale hydrogen production. Transition metal phosphides (TMPs) were proved to be efficient electrocatalysts for HER. In this work, we first synthesized the nickel-molybdenum bimetallic precursors, followed by high-temperature calcination in air. Finally, NiMoP/MoP nanorods (Ni–Mo–P NRs) was obtained by chemical vapor deposition (CVD) of phosphating. The target catalyst of Ni–Mo–P NRs was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). For Ni–Mo–P NRs, the electrochemical test in 0.5 M H 2 SO 4 solution for HER showed that the optimal feeding ratio was Ni:Mo = 1:1. And the Ni 1 –Mo 1 –P NRs presented an onset potential of 63.2 mV, and an overpotential of 117.9 mV was required to drive the current density of 10 mA cm −2 . Meanwhile, The Tafel slope, exchange current density ( j 0 ), electrochemical double-layer capacitance ( C dl ) were 58.6 mV dec −1 , 0.10 mA cm −2 , 12.6 mF cm −2 , respectively. Moreover, there was no obvious activity diminish of Ni 1 –Mo 1 –P NRs after a long-term stability and durability test.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
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IF 4.939
Lina Wu,Yujin Ji,Ding Dai,Ting Chen,Dashuai Yang,Yuanyue Liu,Zhijiang Wang
Electroreduction of N 2 to ammonia (NH 3 ) under ambient conditions, driven by renewable electricity, provides a promising alternative to the Haber-Bosch process and can reduce over 90% of CO 2 emissions via NH 3 synthesis. However, this process suffers from the shortage of efficient electrocatalysts . Herein, we report the size-dependent catalytic activity of Mo nanoparticles (NPs) in the size range of 1–10 nm for the electrochemical synthesis of NH 3 from N 2 and H 2 O. Current density drastically increases as Mo size decreases. The mass activity of 1.5 nm Mo NPs reaches 27.6 μg h −1 mg −1 cat. , which is higher than that of the best noble metal catalyst under comparable reaction conditions. Density functional theory (DFT) calculations show that the enhanced activity with a small size is due to an increase in edge sites between (110) and (100) surfaces. This condition weakens the binding of ∗NH 2 and lowers the energy barrier of the second NH 3 desorption at the determining step.
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NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 24
·9652-9657
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IF 3.069
Zhengnan Wang,Xingbo Ge,Zhihao Li,Jing Wu,Zihao Liang,Shuang Wang
Developing a robust earth-abundant metal electrocatalyst for the hydrogen evolution reaction (HER) in both alkaline and acidic electrolytes is essential for pursuing the highly-efficient conversion of sustainable energy resources. The Mo-doped NiCu electrode was fabricated as a HER catalyst via a one-step electrodeposition process. The structure and the chemical state of the deposited catalysts were characterized by X-ray power diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. This Mo-doped NiCu electrode (8 at% Mo-content in solvent) exhibits outstanding electrocatalytic activity for the HER in an alkaline electrolyte as compared to bimetallic NiMo and NiCu catalysts, with a small overpotential of 95 mV at a current density of 10 mA cm−2 and excellent electrochemistry stability.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
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IF 3.014
Lingpu Jia,Yaxin Zhou,Yimin Jiang,Aihua Zhang,Xin Li,Chunming Wang
A novel Mo doped reduced graphene oxide/polyimide (Mo-rGO/PI) composite membrane sensor for dopamine (DA) has been successfully prepared by a simple and effective method. In this work, the rGO was doped into PI to prepare polymer composite membrane . Although rGO has a certain degree of catalytic activity for DA, more important is Mo doped rGO/PI film can enhance its electrocatalytic activity towards the oxidation of DA, and so far there is almost no report that MoO 2 can catalyze DA. In order to find the best film, different doped ratios of Mo powder are further investigated, and the combined characterization by X-ray photoelectron spectra and energy-dispersive X-ray spectroscopy indicate that Mo exist in rGO/PI film in the form of MoO 2 . Under optimal conditions, the Mo doped rGO/PI film exhibits excellent catalytic activity to DA, with a linear response throughout the concentration range from 0.1 to 2000 μM, it also shows long-term stability and good reproducibility, and performs well for detection of DA in human blood serums and injection. These results suggest that the novel Mo-rGO/PI film is a promising candidate for the accurate and reliable detection of DA signals in biological samples.
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ChemNanoMat
·
2024
·
IF 2.6
Delong Yang,Ziting Du,Jinhang Dai,Qingya Cao,Zhaobao Xiang,Gang Chen,Fukun Li
Here, a series of nitrogen-doped carbon (NC) supported transition metal oxide catalysts were prepared by pyrolysis of chitosan-metal salt mixtures for the efficient synthesis 2,5-diformylfuran (DFF) from 5-hydroxymethylfurfural (HMF) and fructose. Among them, supported molybdenum-based species on nitrogen-doped carbon (Mo/NC) exhibited excellent activity and selectivity for selective oxidation of HMF to DFF. The presence of nitrogen species reduces the electron cloud density around the Mo species, thereby improving the catalytic activity. Moreover, the interaction between active MoO2 species on the catalyst surface and NC ensured the stability of the catalyst, resulting in no significant loss of activity after four catalytic cycles. 99.5% and 55.1% yields of DFF with full conversion were obtained from HMF and fructose respectively over Mo/NC-chitosan-600 in DMSO under ambient air. In order to enhance DFF yield from fructose, sulfonate groups were introduced into Mo/NC-chitosan-600 catalyst, leading to the highest DFF yield of 70.2%. In addition, this catalyst also allowed 10.0%, 22.9% and 33.3% DFF yields from glucose, sucrose and inulin, respectively.
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NEW JOURNAL OF CHEMISTRY
·
2025
·
IF 2.5
Ruiping Wei,Mingzhu Yao,Ziqi Wang,Huijun Liu,Rongying Xia,Lei Yang,Guanghui Ma,Lijing Gao,Xiaomei Pan,Guomin Xiao
The properties of support have significant effects on the catalytic performance of supported catalysts. The present study involves the synthesis of a series of Mo-modified NbOPO4 supports, which were subsequently utilized for the preparation of supported NiCu bimetallic catalysts via a hydrothermal method. All catalysts were evaluated in the HDO of oleic acid to long-chain alkanes without carbon loss, an essential procedure for contemporary industrial applications. The effects of acidity and porosity on the dispersity and valence states of the metal components were systematically investigated via BET, XRD, SEM, XPS, NH3-TPD, and H2-TPR. Catalytic performance of the materials for HDO of oleic acid was assessed and it revealed that NiCu supported on Mo-modified NbOPO4 exhibited significantly enhanced selectivity for C18 compared to those supported on NbOPO4 (53.10% VS 84.16%) under the mild reaction condition of 250 °C reaction temperature, 3 MPa initial H2 pressure and 7 h reaction time. The resluts demonstrated the significant potential of Mo-modified NbOPO4 as a support for NiCu bimetallic catalysts, enabling efficient conversion of oleic acid into C18 and highlighted the crucial role of support modification in enhancing catalytic performance.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Ke Huang,Shicheng Yuan,Rongyan Mei,Ge Yang,Peng Bai,Hailing Guo,Chunzheng Wang,Svetlana Mintova
A chlorine-free catalyst consisting of zeolite Y modified with Pd (Pd/NaY) catalyst has been prepared and used in the indirect oxidative carbonylation of methanol to dimethyl carbonate (DMC). The activity and stability of the catalyst were further improved by introducing molybdenum into Pd/NaY using a top-down approach (Pd-Mo/NaY catalyst). The Pd-Mo/NaY catalyst exhibited higher stability compared to the Pd/NaY. A high CO conversion of 97% and DMC selectivity of 80% during a 30-hour catalytic test for the Pd-Mo/NaY were obtained. Furthermore, the incorporation of Mo was found to partially heal the silanols and hinder the aggregation of Pd in the Pd-Mo/NaY catalyst. The interactions between Mo and Pd increased the amount of active Pd 2+ species and enhanced the adsorption of CO reactant on the Pd-Mo/NaY catalyst. The key reaction intermediate of COOCH 3 * was captured by in situ diffuse reflectance infrared Fourier transform spectroscopy . The stabilization of active Pd 2+ species contributed to the enhanced catalytic activity of the Pd-Mo/NaY catalyst in the indirect oxidative carbonylation of methanol to DMC reaction.
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CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Changqu Lin,Lulu Xu,Yue Zhuang,Peipei Ma,Hongli Wu,Haifeng Gan,Fei Cao,Ping Wei
The cleavage of C-C bonds to generate small molecules is a pivotal strategy for integrating shell bio-refinery products into the conventional chemical industry. Herein, we synthesized a novel bifunctional acetylacetone molybdenum-based catalyst with oxygen vacancies and acid sites (Ov-Mo-acac), which catalyze the retro -aldol reaction of N -acetylglucosamine (NAG), consequently the condensation with acetylacetone and dehydration to co-produce furan and pyrrole compounds. Reaction optimization resulted in a remarkable yield of 95 % for N-acetyl-3-acetyl-2-methyl pyrrole (AMAP) and 74 % for 5-(1,2-dihydroxyethyl)-2-methyl-3-acetylfuran (DMAF) from NAG at 90 ℃ for 3 h. XPS, EPR, and Raman confirmed the reduction of molybdenum from the Mo 6+ to Mo 5+ and Mo 4+ , and oxygen vacancies on the surface. Furthermore, the catalyst has Lewis and Brønsted acidic sites, as evidenced by py-FTIR and 1 H MAS NMR. The study offers a new approach to utilizing shellfishery waste and sheds the function of oxygen vacancies on Mo-based catalysts for the retro -aldol reaction of carbohydrates.
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高影响因子
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