JOM
·
2022
·Vol. 74
·期 7
·2742-2749
·
IF 2.597
Zhang Rui-Hua,Hao Zhen-Hua,Shi Lin-Yuan,Chen Hao-Tian,Shu Yong-Chun,He Ji-Lin
In this present study, carbothermic reduction process of MoO 3 to produce MoO 2 has been carried to investigate the influences of reaction temperature and distance between activated carbon and MoO 3 on phase composition of reduction products by controlling carbon diffusion. Results show that the reduction degree increases with the increase of temperature and the decrease of distance between activated carbon and MoO 3 . MoO 3 can be completely reduced to MoO 2 at 680°C with the carbon distance of 1 mm. It is found that the transformation from MoO 3 to MoO 2 is a process of crystal cracking and growth by observing the phase transition and morphological evolution during the reduction. The massive MoO 3 is first decomposed into a platelet-shaped MoO x (2.75 < x < 3), then the platelet-shaped MoO x changes into a needle-like shape or irregular platelet-like Mo 4 O 11 , and finally Mo 4 O 11 changes into irregular granular or irregular platelet-like shaped crystals, which form MoO 2 powders.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2023
·
IF 3.8
Yuhui Chen,Ruihua Zhang,Zhenhua Hao,Yongchun Shu,Jilin He
In this study, MoO 2 was reduced by an unmixed carbon reduction method. Effects of reduction temperature, reduction time and distance between carbon and MoO 2 on the phase composition of reduction products were investigated. Results show that the phase change during the reduction process are MoO 2 →Mo 2 C→Mo with the increase of temperature. The reduced product is Mo 2 C when reduction temperature is 1000 °C and 1050 °C. Pure Mo can be obtained when the reduction temperature increases to 1100 °C. The reduced product changed from nearly spherical Mo particles with fine molybdenum dioxide particles attached on surface to polyhedron Mo particles with smooth surface when the distance between carbon and MoO 2 decreases from 10 mm to 1 mm. The reaction showed a similar change with the changes of the reaction time. The difference is that there will be residual Mo 2 C in reduced product when reduction time was 1 h. This method of carbon reduction can provide low carbon concentration by controlling the carbon distance to avoid the existence of molybdenum carbide in the product of molybdenum preparation.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
·
2021
·Vol. 30
·期 5
·3484-3491
·
IF 1.819
Gao Yong,Zhang Haibo,Xu Zengshi
Molybdenum trioxide holds the promise of high-performance cathodes for lithium-ion batteries. This study introduces a facile one-step method for large-scale synthesizing B, C co-doped α -MoO 3 single crystals by simultaneous decomposition of boric acid, carburization and vapor deposition on a molybdenum substrate. Experimental characterizations indicate that the B and C co-doping promotes the carrier mobility by inducing impurity states near the Fermi level. Additionally, when subjected to the high voltage, the Mo-C and Mo-B bonds become the controlling factors for enhancing the structural stability through the reduced interplanar spacing which facilitates the restriction of transition-metal ion migration. The target material delivers a high discharge capacity of 305 mAh g −1 with initial Coulombic efficiency of 98%, and shows remarkable cycle stability with a specific capacity of 280 mAh g −1 after 80 cycles. This study sheds light on a new strategy for designing and controlling of the doping activity in other transition-metal-oxides for next-generation lithium-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
POLYMER INTERNATIONAL
·
2017
·Vol. 67
·期 4
·445-452
·
IF 2.07
Mengjiao Zhang,Weihong Wu,Shaorui He,Xue Wang,Yunhong Jiao,Hongqiang Qu,Jianzhong Xu
The synergistic effects of activated carbon (AC) and molybdenum oxide (MoO 3 ) in improving the flame retardancy of poly(vinyl chloride) (PVC) were investigated. The effects of AC, MoO 3 and their mixture with a mass ratio of 1:1 on the flame retardancy and smoke suppression properties of PVC were studied using the limiting oxygen index and cone calorimeter tests. It was found that the flame retardancy of the relatively cheaper AC was slightly weaker than that of MoO 3 . In addition, the incorporation of AC and MoO 3 greatly reduced the total heat release and improved smoke suppressant property of PVC composites. When the total content of AC and MoO 3 was 10 phr, PVC/AC/MoO 3 had the lowest peak heat release rate and peak smoke production rate values of 173.80 kW m −2 and 0.1472 m 2 s −1 , which represented reductions of 47.3 and 59.9%, respectively, compared with those of PVC. Furthermore, thermogravimetric analysis and gel content tests were used to analyze the flame retardant mechanism of AC and MoO 3 , with results showing that AC could promote early crosslinking in PVC. Char residue left after heating at 500 °C was analyzed using scanning electron microscopy and Raman spectroscopy, and the results showed that MoO 3 produced the most compact char, with the smallest and most organized carbonaceous microstructures. © 2017 Society of Chemical Industry
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2024
·Vol. 14
·期 14
·1189
·
IF 4.4
Jian Yu,Zhaokang Zheng,Aiwu Wang,Muhammad Humayun,Yasser A. Attia
Molybdenum trioxide (MoO3) is an attractive semiconductor. Thus, bandgap engineering toward photoelectronic applications is appealing yet not well studied. Here, we report the incorporation of sulfur atoms into MoO3, using sulfur powder as a source of sulfur, via a self-developed hydrothermal synthesis approach. The formation of Mo-S bonds in the MoO3material with the synergistic effect of sulfur doping and oxygen vacancies (designated as S-MoO3−x) is confirmed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The bandgap is tuned from 2.68 eV to 2.57 eV upon sulfur doping, as confirmed by UV-VIS DRS spectra. Some MoS2phase is identified with sulfur doping by referring to the photoluminescence (PL) spectra and electrochemical impedance spectroscopy (EIS), allowing significantly improved charge carrier separation and electron transfer efficiency. Therefore, the as-prepared S-MoO3−xdelivers a sensitive photocurrent response and splendid cycling stability. This study on the synergistic effect of sulfur doping and oxygen vacancies provides key insights into the impact of doping strategies on MoO3performance, paving new pathways for its optimization and development in relevant fields.
研究领域:
材料科学
·
半导体物理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2016
·Vol. 4
·期 48
·11449-11456
·
IF 5.066
Xiaolong Lu,Rongguo Wang,Lifeng Hao,Fan Yang,Weicheng Jiao,Jian Zhang,Ping Peng,Wenbo Liu
After UV irradiation of orthorhombic molybdenum trioxide (α-MoO3) nanosheets dispersed in two different solvents including water/ethanol mixed solvents and individual N-methyl-2-pyrrolidinone (NMP), we observed remarkable but distinct morphology changes in combination with different photochromic phenomena. MoO3−x quantum dots (QDs) with both different sizes and oxygen vacancy concentrations could be acquired through this facile and efficient method. The consumption of photoexcited holes played an important role in the morphology changes. In water/ethanol, intercalation of H+ originating from the oxidation of water by photoholes contributes to the acquisition of QDs. While in NMP, we provided a new insight and proved that photocorrosion induced by accumulated holes was responsible for the morphology evolution and acquisition of QDs.
研究领域:
材料科学
·
纳米技术
✓ 已验证
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 5
·493
·
IF 4.501
Gengzhe Song,Qi Wang,Liang Yang,Duohua Liao,Shuang Li
A series of the layered double oxides supported molybdenum oxide catalysts were synthesized and evaluated in the oxidative dehydrogenation of ethane with CO2(CO2-ODHE). The 22.3 wt% Mo/LDO catalyst delivered a 92.3%selectivity to ethylene and a 7.9% ethane conversion at relatively low temperatures. The molybdenum oxide catalysts were fully characterized by XRD, BET, SEM, TEM, UV–vis, Raman TG, and XPS. Isolated [MoO4]2−dominated on the surface of the fresh 12.5 wt% Mo/LDO catalyst. With the increase of the Mo content, the Mo species transformed from [MoO4]2−to [Mo7O24]6−and [Mo8O26]4−on the 22.3 wt% and 30.1 wt% Mo/LDO catalysts, respectively. The redox mechanism was proposed and three Mo species including [MoO4]2−, [Mo7O24]6−, and [Mo8O26]4−showed quite different functions in the CO2-ODHE reaction: [MoO4]2−, with tetrahedral structure, preferred the non-selective pathway; [Mo7O24]6−, with an octahedral construction, promoted the selective pathway; and the existence of [Mo8O26]4−reduced the ability to activate ethane. This work provides detailed insights to further understand the relationship between structure–activity and the role of surface Mo species as well as their aggregation state in CO2-ODHE.Keywords:ethane;oxidative dehydrogenation;molybdenum oxide;CO2;Mo/LDO catalyst
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Composites Science
·
2021
·Vol. 5
·期 8
·207
·
IF 0
Ying Zhou,Cuihuan Song,Zhixiang Chen,Qixin Zhou
In this study, we prepared a novel coating composed of hexagonal molybdenum oxide (h-MoO3) nanofiller and waterborne epoxy resin (WEP) to provide corrosion protection. We optimized the h-MoO3nanorod synthesis methodology first by changing different parameters (pH, temperature, etc.). Furthermore, the as-prepared h-MoO3rods were characterized using a scanning electron microscope (SEM) and X-ray diffraction (XRD). Finally, the electrochemical impedance spectroscopy (EIS) test results verified that the anticorrosive performance of the composite coatings was improved by incorporation of low content of MoO3nanofiller (0.5 wt.%) compared to pure WEP sample. This developed composite will provide a new insight for the design and fabrication of one-dimensional (1D) nanomaterial (e.g., nanorod) reinforced epoxy coating and other polymeric coating processes.Keywords:waterborne epoxy;molybdenum trioxide nanorod;composites
研究领域:
材料科学
·
腐蚀防护
✓ 已验证
产品关联
DOI
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
·
2016
·Vol. 254
·期 4
·1600245
·
IF 1.522
Song Hao,Bingchu Yang,Yongli Gao
Monolayer MoS 2 is an emerging two-dimensional semiconductor with wide-ranging potential applications in novel optoelectronic devices and catalysis. Here, we report the growth of drop-like monolayer MoS 2 /MoO 2 granular films on SiO 2 /Si substrate by chemical vapor deposition method. The as-synthesized films were systematically characterized by various means of optical microscopy, X-ray/ultraviolet photoemission spectroscopy, scanning electron microscopy, atomic/kelvin force microscopy, X-ray diffraction, Raman and photoluminescence techniques. The combined results of atomic force microscopy and scanning electron microscopy clearly present novel drop-like granulars and domain boundaries, ascribed to lower growth temperature. X-ray photoemission spectroscopy results complemented by Raman and X-ray diffraction results confirm the formation of MoS 2 /MoO 2 granular films. The ultraviolet photoemission spectroscopy, along with kelvin force microscopy, reveals a different nature of surface potential of drop-like MoS 2 granular films compared with crystalline MoS 2 , owing to electron transfer from MoS 2 to MoO 2 and drop-like structure. Our study broadens the scope of two-dimensional transition metal dichalcogenides research and reveals the distinct physical properties of drop-like monolayer MoS 2 granular films.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
SOLAR ENERGY
·
2020
·
IF 4.608
Yu Zhang,Ping Su,Linqing Liu,Pengfei Qiu,Li Su,Guangsheng Fu,Wei Yu
Achieving large Fermi energy splitting under illumination is critical for improving the performance of photovoltaic devices. In this work, we conducted the energy band structure modulation of MoS 2 thin films via MoO x doping scheme to realize its photovoltaic operation on n-type c-Si by magnetron sputtering. It is found that, by capping a MoO x overlayer, the MoS 2 electrons density decreased and the Fermi level shifted ~0.4 eV towards valence band, consequently the MoS 2 conductive type changing. With this doped MoS 2 layer, the built-in electric field of fabricated MoS 2 /n-Si heterojunction devices greatly improved and exceeded 400 mV owing to the larger interface energy-level differences. Meanwhile, the defects recombination losses reduced benefiting from the holes-selective behavior of O-deficiencies in MoO x , so that the photo-generated carriers extraction process were promoted. As a result, the doped MoS 2 /n-Si devices showed excellent rectification behavior with rectifying ratio to 10 5 and ideality of 1.12. The TRPL spectrums corroborated the enhanced carrier transport mechanism at MoS 2 /n-Si interface by MoO x modulation doping effect. Correspondingly, the significant improvement of doped MoS 2 /n-Si solar cells performance (V oc of 289 mV, FF of 60.72% and J sc of 31.25 mA/cm 2 ) was achieved, exhibiting an optimized conversion efficiency of 5.47%. The UPS analysis revealed that the doping mechanism of MoO x /MoS 2 stacks lies in energy band overlap and electrons contact transfer between these two materials. This observation of MoO x modulation doping effect on large-area sputtering MoS 2 could help in building a better interface carrier transport in photovoltaic and optoelectronic applications of 2D materials.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 9
·3786-3793
·
IF 3.288
Panpan Zhang,Yibin Tong,Mingyuan Zhu,Bin Dai
MoO2/ZrO2–SiO2 catalysts were successfully synthesized using a facile calcination route, and their performance in the oxidative desulfurization process was studied. Experimental results revealed that 5% MoO2/ZrO2–SiO2 exhibited the highest catalytic activity. The properties of the catalysts were investigated using methods such as X-ray photoelectron spectroscopy, Fourier-transform infrared and Transmission electron microscopies. X-ray diffraction confirmed that MoO2 was present in the ZrO2–SiO2 support. Temperature programmed desorption of NH3 proved that the MoO2/ZrO2–SiO2 catalyst has more acid sites. The reaction conditions were optimized in the oxidative desulfurization process. The sulfur removal rate was 99.96% under the optimum reaction conditions of 0.06 g catalyst, 298 K, and O/S = 4, for 30 min. After eight cycles, the activity of the catalyst decreased to 88.65%.
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Qingqing Jiang,Sha Hu,Lin Wang,Zhengxi Huang,Hai-Jian Yang,Xiaole Han,Yongxiu Li,Chao Lv,Yu-Shi He,Tengfei Zhou,Juncheng Hu
Considering the suitable redox potential, low price, and abundant resource of potassium, potassium-ion batteries (PIBs) have attracted considerable attention as one of the alternatives to lithium-ion batteries (LIBs), however, the larger ionic radius of potassium ions makes it difficult to select suitable electrode materials. Herein, the MoSe 2 @MoO 2 heterojunction in which MoO 2 nanoparticles embedded on MoSe 2 nanosheets was synthesized by hydrothermal method and used as a novel anode material for PIBs. The electrochemical performance of the heterojunction was greatly improved as compared with the pure MoSe 2 and pure MoO 2 . At the current density of 500 mA g −1 after 100 cycle, the heterojunction electrode still maintains a capacity of 255 mA h g −1 and the coulomb efficiency is close to 100%. By introducing metallic MoO 2 can improve the electrical conductivity, furthermore, the MoSe 2 @MoO 2 heterostructures facilitate interfacial electron transport and built-in electric field makes the diffusion of K-ion easier. In addition, the well dispersed MoO 2 nanoparticles prevent the restacking of MoSe 2 nanosheets and maintain the structure stability during the charge/discharge process.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）