Energy Technology
·
2020
·Vol. 8
·期 7
·1901392
·
IF 3.404
Jing Tong,Yanan Xue,Jianzhi Wang,Miao Wang,Weimin Chen,Qifeng Tian,Faquan Yu
The development of highly efficient, economical, and sustainable electrocatalysts based on non-noble metals for hydrogen evolution reaction (HER) is of vital significance for large-scale renewable energy storage. Herein, an effective synthetic strategy for the construction of MoO 2 nanoflowers decorated with metallic Cu/Cu 2 O nanoparticles (NPs) on Ni foam (NF) (Cu 2 O/MoO 2 @Cu/NF) with a simple two-step method is reported. The prepared Cu 2 O/MoO 2 @Cu/NF as an electrocatalyst exhibits outstanding reactivity and remarkable stability in alkaline solution. The onset overpotential of Cu 2 O/MoO 2 @Cu/NF approaches 0 V. An overpotential as low as 32 mV is obtained to afford a current density of 10 mA cm −2 , comparable with Pt/C catalysts. The Tafel slope is low at 40 mV dec −1 as well. The involvement of zero-valent Cu greatly reduces the resistance. The well-dispersed Cu/Cu 2 O NPs on the sphere-like MoO 2 nanoflowers exaggerate the surface area. The ringent channels provide the fast release of evolved bubbles. Furthermore, the enhanced conductivity and large surface area lead to significant activity in HER. Herein, a novel design and facile synthesis of a highly efficient electrocatalyst with catalytic activity that is comparable to a Pt/C catalyst is provided.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 41
·19790-19801
·
IF 3.925
Chaofei Guo,Yaomeng Yao,YingNan Cao,Qin Feng,Yifan Zhang,Yong Wang
Molybdenum disulfide (MoS2), with its unique two-dimensional nanostructure and high theoretical capacity, is considered a promising electrode for lithium-ion batteries (LIBs). However, the disadvantages of MoS2 electrodes include low electronic conductivity, sluggish cation kinetics, serious volume change, poor cycle stability, and inefficient rate performance of lithium storage. Herein, oxygen vacancy and heterostructure engineering are rationally involved in revealing the moderate oxygen vacancy in the hierarchical tubular heterostructure material (MoS2@MoO2) via a self-template method as a highly active LIB electrode. Due to the presence of the moderate oxygen vacancies and heterojunction structure of MoS2@MoO2-4, the diffusion pathway and barrier for lithium ions can be significantly reduced, accelerating the ionic diffusion rate and further promoting the reaction kinetics. The electrode achieves a high reversible capacity of 1200.1 mA h g−1 at 100 mA g−1 after 100 cycles with the optimum regulation of the sulfur contents and the moderate oxygen vacancy (MoS2@MoO2-4). Additionally, good rate capability is obtained at stepwise current densities due to the merits of MoS2@MoO2. A series of measurements such as EPR, XPS, in situ XRD, and in situ Raman are also employed to reveal the synergistic effect in the midst of oxygen vacancies and heterostructures for lithium storage. All results prove that the moderate oxygen vacancy and tubular heterostructure can implement faster Li+ transport and lower the diffusion barrier of lithium ions, resulting in enhanced lithium storage performance of MoS2@MoO2.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Zeting Deng,Xiangbowen Du,Kaicheng Qian,Leilei Du,Zheng Fang,Jiayang Zhu,Jia Hong,Feng Wang,Tongtong Li,Tong Wei,Renhong Li
The conventional anodic oxygen evolution reaction (OER) can be ideally replaced by the urea oxidation reaction (UOR) to achieve efficient hydrogen generation due to the superior thermodynamics. However, the UOR involves a slow 6-electron transfer dynamic, necessitating the utilization of high-performance catalysts to enhance catalytic efficiency. In this work, a bifunctional transition metal-based catalysts, namely, MoO 2 –NiO/NF heterostructure, is effectively synthesized using two-step hydrothermal methods and calcination. Benefiting from the heterogeneous interface, the nanoflower-like structure as well as the electron density redistribution, the MoO 2 –NiO/NF catalyst demonstrates remarkable durability and performance, with an overpotential of 139 mV to achieve 10 mA cm −2 for UOR. In addition, the bifunctional catalyst is used in a two-electrode electrolyzer, where a current density of 10 mA cm −2 is attained at a potential of 1.317 V, which is 261 mV smaller than that of the conventional water splitting system. Based on the density functional theory (DFT) calculations, the MoO 2 –NiO/NF heterostructure exhibits a higher density cloud in the vicinity of the Fermi level, revealing that it has faster electron transfer and higher electrical conductivity. Besides, the Mo sites and Ni sites are favorable for adsorption of CO(NH 2 ) 2 and H 2 O, respectively, which might optimize the reaction intermediates adsorption/desorption for UOR/HER, ultimately leading to the high electrocatalytic performance of MoO 2 –NiO/NF. This research opens a new window for the development of advanced heterojunction electrocatalysts assisted by urea electrocatalysis for cost-effective hydrogen production.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2016
·Vol. 26
·期 46
·8537-8544
·
IF 11.382
Xiaoshuang Chen,Guangbo Liu,Wei Zheng,Wei Feng,Wenwu Cao,Wenping Hu,PingAn Hu
Electrochemical water splitting is very attractive for green fuel energy production, but the development of active, stable, and earth-abundant catalysts for the hydrogen evolution reaction (HER) remains a major challenge. Here, core–shell nanostructured architectures are used to design and fabricate efficient and stable HER catalysts from earth-abundant components. Vertically oriented quasi-2D core–shell MoO 2 /MoSe 2 nanosheet arrays are grown onto insulating (SiO 2 /Si wafer) or conductive (carbon cloth) substrates. This core–shell nanostructure array architecture exhibits synergistic properties to create superior HER performance, where high density structural defects and disorders on the shell generated by a large crystalline mismatch of MoO 2 and MoSe 2 act as multiple active sites for HER, and the metallic MoO 2 core facilitates charge transport for proton reduction while the vertical nanosheet arrays ensure fully exposed active sites toward electrolytes. As a HER catalyst, this electrode exhibits a low Tafel slope of 49.1 mV dec −1 , a small onset potential of 63 mV, and an ultralow charge transfer resistance ( R ct ) of 16.6 Ω at an overpotential of 300 mV with a long cycling durability for up to 8 h. This work suggests that a quasi 2D core–shell nanostructure combined with a vertical array microstructure is a promising strategy for efficient water splitting electrocatalysts with scale-up potential.
研究领域:
材料科学
·
电化学
·
能量转换
·
纳米技术
·
催化
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Wanli Liang,Mengyan Zhou,Xiulan Li,Lijie Zhu,Zhixin Li,Yifan Zhou,Jian Chen,Fangyan Xie,Hao-Fan Wang,Nan Wang,Yanshuo Jin,Hui Meng
Hydrogen energy is the most suitable solution for long-term, large-scale energy storage, and the design of efficient, economical, and stable electrocatalysts for hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is of great significance for its commercial development. Herein, Ni nanocluster supported on oxygen-vacancy-rich MoO 2 (Ni/MoO 2−x ) is designed which contains a large number of oxygen vacancies and Ni–O–Mo bonds. According to X-ray photoelectron spectroscopy, the formation of oxygen vacancies and Ni–O–Mo bonds facilitates the transfer of electrons from Ni to O. The prepared Ni/MoO 2−x @NF shows excellent hydrogen electrocatalytic activity, which is proved by a Tafel slope of only 26 mV dec −1 for HER and an exchange current density of 3.64 mA cm −2 for HOR. Theoretical calculations showed optimized free energy of hydrogen adsorption and hydroxide adsorption on Ni/MoO 2−x , which can explain the origin of the high activity of the catalyst. This work provides a feasible strategy for designing non-precious metal hydrogen electrocatalytic materials in energy storage.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 20
·17571-17579
·
IF 2.324
Zhong Canyu,Lai Qi,Liao Xianjie,Li Yufeng,Wu Jinggao
Porous Ti-doped MoO 2 was successfully synthesized through one-pot hydrothermal method and used as an anode material for lithium ion batteries (LIBs). It delivers an initial discharge capacity of 1290 and 410 mAh/g at current density of 20 and 1000 mA/g, respectively. Electrochemical cycle test shows that the discharge capacity of 740 mAh/g can be obtained after 80 cycles at current density of 200 mA/g, with 78.06% capacity retention and almost 100% columbic efficiency. The electrochemical performances are much better than that of other MoO 2 -based materials. This could be assigned to the porous structure that increased contact areas between electrode materials and electrolytes, much faster electron transport confirmed via electrochemical impedance spectroscopy (EIS) analysis and Density functional theory (DFT) calculations.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2015
·Vol. 2
·期 9
·095502
·
IF 0
Jipeng Guan,Liping Zhao,Chenyang Xing,Yongjin Li
In this work, a novel flexible MWCNTs@MoO2-C nanocable composite for lithium ion battery anodes was fabricated by the electrospinning of homogeneously dispersed MWCNTs in a PVA/ammonium molybdate tetrahydrate solution and subsequent thermal treatment of the electrospun nanofibers. In the resulting MWCNTs@MoO2-C nanocable composite, the MoO2 nanoparticles were uniformly dispersed in amorphous carbon nanofibers that contained well-embedded MWCNTs as their cores. Compared with samples without MWCNTs, the unique nanocable composite exhibited not only a high specific capacity but also excellent cycling performance and good flexibility. It delivered a high reversible capacity of 832 mAh g−1 at a current density of 50 mA g−1 after 30 cycles. The enhanced electrochemical performance of the MWCNTs@MoO2-C nanocable composite was attributed to its novel nanocable structure ensuring not only effective contact between MoO2 and the liquid electrolyte, but also high conductivity for Li+ and e– transfer.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
产品关联
DOI
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 46
·17235-17240
·
IF 4.39
Liujun Deng,Yu Zou,Jiang Jiang
Plasmonic hybrid catalysts have attracted great interest for the reduction of nitrobenzene waste to valuable aminobenzene, because they can use renewable solar energy to accelerate the catalytic reaction. However, the economical synthesis of non-precious plasmonic hybrid catalysts remains a big challenge. Herein we report the synthesis of plasmonic MoO2-embedded MoNi4 nanosheets (MoNi4–MoO2) by thermal annealing of NiMoO4 at 600 °C under a hydrogen atmosphere. The MoNi4–MoO2 hybrid catalysts retain strong plasmon absorption from MoO2 and demonstrate good catalytic activity from MoNi4 for 4-nitrophenol reduction in the dark. Under visible light irradiation, the excitation of MoO2 plasmon promotes the catalytic reaction further due to hot electron-induced increase of catalytic activity of MoNi4. In addition, the hybrid catalysts are relatively stable even under illumination reaction conditions.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Chao Liu,Peng-kai Fan,Xiao-qi Xie,Ying-jie Sun,Yan Li,Xiao-jing Wang
Generally, it is important to ameliorate the co-catalyst used in photocatalytic hydrogen evolution reactions (PHERs) to achieve efficient transfer and separation of photogenerated carriers, decrease the surface reaction energy barrier, and hence improve the photocatalytic activity . In this study, N-doped graphite carbon (GC) was introduced in situ to MoO 2 to ensure the presence of well-dispersed active sites, lower the overpotential of hydrogen evolution, and further achieve high conductivity. Then, the MoO 2 /GC composite obtained was used as a co-catalyst of ZnIn 2 S 4 (ZIS) in a PHER, resulting in a great improvement in the photocatalytic activity. Given the metallicity and large work function of MoO 2 /GC, a Schottky interface can form between MoO 2 /GC and ZIS, which accelerates the transmission of photogenerated electrons. As a result, the separation efficiency of photogenerated carriers improves, whereas the surface overpotential of PHERs clearly decreases for ZIS. This study proposes a new idea for exploiting efficient co-catalysts and promotes the wide and heavy use of carbon materials in the field of solar energy conversion .
研究领域:
材料科学
·
太阳能转换
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Aming Xie,Jiajia Wang,Cheng Zhang,Siyao Cheng
In this work, the dielectric loss behavior and electromagnetic wave absorption (EMA) property of MoO 2 ceramic from single crystal to polycrystal have been in-depth investigated. It is found that polycrystal MoO 2 shows better dielectric loss ability than single crystal MoO 2 , leading to greatly enhanced EMA performance. It is determined that polarization loss occupies the dominant position in the dielectric loss of MoO 2 ceramic. This research provides new insights in understanding of dielectric loss behavior and EMA mechanism for dielectric MoO 2 crystals.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2023
·Vol. 33
·期 51
·2308191
·
IF 19
Jianxi Lu,Songbo Chen,Yuling Zhuo,Xinya Mao,Dong Liu,Zhenbo Wang
Hydrogen production through seawater electrolysis faces several challenges, one of which involves the development of electrocatalysts with high catalytic performance. Here, surface amorphization and morphology engineering are combined to design a novel electrocatalyst for highly-efficient hydrogen evolution reaction (HER). The surface-amorphized MoO 2 /Ni 3 (PO 4 ) 2 microcolumns supported on nickel foam (SA-MoO 2 /Ni 3 (PO 4 ) 2 /NF) display remarkable performance with low overpotentials of 34 and 46 mV at a current density of 10 mA cm −2 in 1 m KOH and alkaline seawater, respectively. In addition, the alkaline electrolysis cell (AEC) integrated with SA-MoO 2 /Ni 3 (PO 4 ) 2 /NF as the cathode and Ni foam as the anode achieves a current density of 100 mA cm −2 at 1.87 V in 6 m KOH seawater at 60 °C, superior to that of industrial NiMo electrode as cathode (2.05 V). DFT calculations demonstrate that the surface amorphous layer (MoO x ) improves the hydrogen adsorption energy of sample and reduces the energy barrier of water dissociation. It is found that substantial improvement in catalytic performance stems from the synergistic effect between surface amorphization and unique microcolumn morphology. These findings may provide insights into combining surface amorphization and morphology engineering strategies to enhance catalytic performance and pave the way for the development of highly efficient seawater HER electrocatalysts.
研究领域:
材料科学
·
能源化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2023
·Vol. 42
·期 8
·2592-2600
·
IF 8.8
Chen Jing,Chen Xuan-Le,Lu Rou,Li Yong,Pan An-Qiang
Molybdenum dioxide has aroused a wide concern as anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and high density. However, it still faces the problems of large volume changes and low electronic conductivities, which limits its practical application. Herein, necklace-like N-doped carbon nanofibers encapsulating MoO 2 nanospheres (MoO 2 @NCNFs) with Mo–C bonding have been designed to address these issues. The rational design carbon coating structure can not only enhance the electron transfer, but also markedly strengthen structural stability. As expected, the as-prepared electrode showed superior lithium storage capacity, including a high specific capacity of 1120 mAh·g −1 at 0.1 A·g −1 , and good rate performance of 502 mAh·g −1 at 4.0 A·g −1 and a prolonged cycling stability of 490 mAh·g −1 capacity retention over 3000 cycles at 4.0 A·g −1 . Graphical abstract
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）