DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 35
·14767-14778
·
IF 3.5
Xuan Liao,Hang Yang,Xiaolong Hou,Caini Yi,Ying Yang,Guimao Wang,Shuo Wang,Yuping Liu,Changguo Chen,Danmei Yu,Xiaoyuan Zhou
To overcome the disadvantages of poor intrinsic conductivity and stability of ZnCo2O4, a ZnCo2O4@MnMoO4 composite as an emerging pseudocapacitor electrode material with high specific capacitance, environmental friendliness, morphological diversity, and unique hierarchical structure was synthesized via a simple two-step hydrothermal method. The research results indicate that the ZnCo2O4@MnMoO4 composite can present a high specific capacity of 1628 F g−1 at a current density of 1 A g−1 and good cycling stability with 69% capacity retention after 10 000 cycles at 10 A g−1. Hybrid supercapacitors (HSCs) assembled with the ZnCo2O4@MnMoO4 cathode and activated carbon anode can deliver an energy density of 48 W h kg−1 at a power density of 695 W kg−1, and their capacity retention reached 61% after 8000 charge–discharge cycles at a current density of 10 A g−1. This could be attributed to the synergistic effect of the specific surface area and electrical conductivity enhanced by compositing ZnCo2O4 with MnMoO4. As a result, the excellent electrochemical properties show that the ZnCo2O4@MnMoO4 composite has strong application potential for high-performance supercapacitors.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Jin Wang,Zhenjun Qing,Xin Zhou,Huapeng Zou,Haiyan Li,An Liu,Shumin Duan,Yingxiang Li
MnMoO 4 ceramic was prepared using solid-state reaction method. XRD and Rietveld refinement results confirmed the formation of a single phase of MnMoO 4 with monoclinic structure of C 2/ m space group. Excellent microwave dielectric properties , including ε r = 9.32, Q × f = 56,230 GHz, and τ f = −62.32 ppm/°C, were achieved for the resulting MnMoO 4 ceramic at 925 °C, which had a relative density of 97%. The dielectric polarization and packing fraction were closely related to the dielectric constant and quality factor of MnMoO 4 ceramics, respectively. Furthermore, our P–V-L analysis demonstrated that the ionicity, lattice energy, and bond energy of chemical bonds were all dominated by the Mo–O bond, which had a greater influence on microwave dielectric properties than the Mn–O bond. This finding was confirmed using Raman spectroscopy , which revealed that [MoO 4 ] tetrahedron vibrations predominated Raman vibrations, supporting the P–V-L theory. Additionally, the chemical compatibility of the MnMoO 4 ceramic with Ag co-firing was explored to investigate potential technological applications.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Cuilian Sun,Huhu Yin,Xiujing Xing,Yaokang Lv,Wei Xiong,Hao Li
In recent years, a variety of catalysts have been applied to electrocatalytic nitrogen reduction (NRR). Previous research has shown that in bimetallic catalysis the synergistic effect between the bimetals results in catalytic properties superior to those of monometallic catalysts. In this work, bimetallic oxide MnMoO4 nanomaterials with different particle sizes were prepared by a solvothermal method, and the effects of different ratios of the solvents (water/ethylene glycol) on the particle sizes of MnMoO4 and their influence on the NRR performance were systematically investigated. The results showed that as the proportion of ethylene glycol solvent increased, scanning electron microscopy (SEM) characterization showed a transformation of morphology from micrometer-scale rods to nanoscale particles, and the smallest MnMoO4 particle size was obtained at a water/ethylene glycol ratio of 0:1. Under this condition, the formed MnMoO4 exhibited excellent NRR properties at −0.40 V vs RHE with an NH3 yield as high as 21.89 μg h–1 mgcat–1 and a Faraday efficiency (FE) of 15.12%, with the best stability among all catalysts synthesized in this work. This may be attributed to the increased viscosity of the ethylene glycol environment, leading to a deceleration of the precursor reactions. This leads to the production of materials with smaller particle sizes, exposing more active sites and improving catalytic performance. In addition, we explored the effect of other solvents (n-butanol and glycerol) on the morphology of the materials. This work indicates that changing the solvent to regulate the morphology and size of the bimetallic oxide MnMoO4 can improve the catalytic efficiency of the catalyst, providing a promising electrocatalyst for nitrogen reduction reactions.
研究领域:
材料科学
·
催化化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 45
·16670-16679
·
IF 4
Huhu Yin,Xiujing Xing,Wei Zhang,Jin Li,Wei Xiong,Hao Li
Electrocatalytic nitrogen reduction (NRR) for artificial ammonia synthesis under ambient conditions is considered a promising alternative to the traditional Haber–Bosch process. However, it still faces multiple challenges such as the difficulty of N2 adsorption and activation and limited Faraday efficiency. In this work, a bimetallic oxide MnMoO4 was prepared by a hydrothermal method and low temperature calcination. The influence of the sintering temperature on the microstructure (crystallinity and oxygen vacancies) of the oxide and its NRR properties were systematically explored. The results showed that MnMoO4 sintered at 500 °C had the highest concentration of OVs and showed excellent NRR performance, with the highest NH3 yield (up to 12.28 μg h−1 mgcat−1), high Faraday efficiency (23.04% at −0.30 V vs. RHE), and good stability at −0.40 V vs. RHE, and the catalytic performance was about two times higher than that of Mn2O3 and MoO3. It is also superior to other bimetallic oxide NRR electrocatalysts reported in some cases. In addition, we also explored the ratio between Mn and Mo metals, and the catalytic effect was the best when Mn : Mo = 1 : 1. Due to the synergistic effect between Mn and Mo metals and the large number of OVs present internally, the catalytic activity for the NRR was largely improved. This study suggests that the bimetallic oxide MnMoO4 may be a promising NRR electrocatalyst.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SOLAR ENERGY
·
2021
·
IF 5.742
Xiaobo Chen,Yang Zhang,Jianghao Cai,Jiangyue Zhu
Carbon cloth (CC) supported core–shell NiCo 2 O 4 @MnMoO 4 nanoarrays composite is successfully synthesized by two-step hydrothermal method, and used as binder-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). In comparison with the NiCo 2 O 4 /CC, MnMoO 4 /CC, CC and Pt CEs, the NiCo 2 O 4 @MnMoO 4 /CC CE exhibits the significantly improved electrochemical performance. And the improved electrochemical performance can be attributed to the contribution from CC combination outer-sphere MnMoO 4 nanosheet and inner-sphere NiCo 2 O 4 nanowires array, which offer a large electrochemical surface area, good electrochemical activity to iodide/triiodide couple, and lower charge-transfer and series resistances. The DSSCs device assembled with core–shell composite NiCo 2 O 4 @MnMoO 4 /CC CE achieved excellent power conversion efficiency of 11.87%, which is higher than that of counter parts of NiCo 2 O 4 /CC (10.97%), MnMoO 4 /CC (11.08%), CC (4.84%) and Pt (8.55%) CEs. Also, the NiCo 2 O 4 @MnMoO 4 /CC based device remains 90.9% efficiency up to 10 days under ambient conditions. Therefore, the NiCo 2 O 4 @MnMoO 4 /CC composite with unique structure can be further developed as an efficient and cost-effective metal oxides electrocatalysts in DSSCs and other related fields.
研究领域:
材料科学
·
电化学
·
可再生能源
·
太阳能电池
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Chunyu Cui,Jiantie Xu,Lei Wang,Di Guo,Minglei Mao,Jianmin Ma,Taihong Wang
Three-dimensional heterostructured NiCo2O4@MnMoO4 nanocolumn arrays (NCAs) on Ni foam were first fabricated through an improved two-step hydrothermal process associated with a successive annealing treatment. The hybrid NiCo2O4@MnMoO4 electrode exhibited remarkable pseudocapacitor property with high initial mass specific capacitance of 1705.3 F g–1 at 5 mA cm–2, and retained 92.6% after 5000 cycles, compared to the bare NiCo2O4 electrode with 839.1 F g–1 and 90.9%. The excellent capacitive property of the NiCo2O4@MnMoO4 hydrid was attributed to its high-electron/ion-transfer rate, large electrolyte infiltrate area, and more electroactive reaction sites.
研究领域:
材料科学
·
电化学
·
纳米材料
·
储能
✓ 已验证
DOI
高影响因子
ChemElectroChem
·
2017
·Vol. 4
·期 10
·2634-2642
·
IF 4.136
Xijun Wei,Yanhong Li,Huarong Peng,Chunli Liu,Yunhuai Zhang,Peng Xiao
Hierarchical NiCo 2 S 4 @MnMoO 4 core-shell structure composites are first designed and fabricated through a three-step hydrothermal process. NiCo 2 S 4 microspheres consisting of nanotubes are utilized as ideal conductive scaffolds, whereas ultrathin MnMoO 4 nanosheets are controllably deposited. This particular structure is beneficial to the migration and diffusion of ions, meaning that the redox reactions of the active materials can be carried out quickly and completely. The NiCo 2 S 4 @MnMoO 4 hybrid electrode shows an ultrahigh specific capacitance of 1186.44 F g −1 at a current density of 1 A g −1 (3.6 F cm −2 at 3 mA cm −2 ). It exhibits good cycling stability with 90.1 % capacitance retention over 5000 cycles at 10 A g −1 . Moreover, an electrochemical energy-storage device is fabricated, where the as-prepared NiCo 2 S 4 @MnMoO 4 is employed as both the cathode and anode. The device achieves a high energy density of 47.8 Wh kg −1 at a power density of 699.9 W kg −1 , as well as excellent cycling stability (88.3 % capacitance retention over 5000 cycles at 10 A g −1 ). The outstanding performance demonstrates that the NiCo 2 S 4 @MnMoO 4 core−shell composite is a promising electrode material for electrochemical energy storage, which may inspire researchers to continue investigating heterostructured materials as energy-storage materials. Graphical Structure is key : A NiCo 2 S 4 @MnMoO 4 core-shell structure is first fabricated by using a three-step hydrothermal process. The composite exhibits improved performance compared to pure NiCo 2 S 4 , owing to the porous structure, rich faradic reaction, and synergistic effect. Moreover, an electrochemical energy-storage device with this material achieves a high energy density and excellent cycling stability in 3 M KOH.
研究领域:
材料科学
·
电化学
·
能量存储与转换
·
纳米材料
·
应用物理
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Qiwei Zhang,Zhenlu Zhao
Transition metal disulfide compounds (TMDs) catalysts exhibit excellent catalytic ability in hydrogen evolution reaction (HER), but they are susceptible to OH- poisoning under strong alkali conditions leading to active site inactivation, thus affecting their catalytic activity and stability. In this regard, we propose a catalyst “self-protection” strategy against OH - attack. Specifically, we synthesized a composite heterojunction MnMoO 4 @CoS 2 /MoS 2 on carbon cloth (CC) by a hydrothermal and calcination process. The experimental results show that MnMoO 4 undergoes reconfiguration during the HER process, and its MoO 4 2- takes the lead in dissolving in the electrolyte before being re-adsorbed on the surface of the electrocatalyst to form a protective layer, which greatly inhibits the erosion of OH - on the catalyst and effectively prevents the oxidation of the Mo 4+ and the edge S sites, which is beneficial to the long-term stability of the catalyst. The CoS 2 /MoS 2 heterojunction provides more active sites and higher conductivity to enhance its catalytic activity. The products exhibit overpotentials of only 71 and 171 mV at current densities of 10 and 100 mA cm −2 , and have long-term stability of over 100 h. In comparison, the samples after base hydrolysis treatment (deprotection) showed a significant performance decay. This study provides a novel approach for the rational design of efficient and stable TMDs catalysts.
研究领域:
催化
·
材料科学
·
电化学
·
纳米技术
·
能量转换
·
表面科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Qinhan Wu,Longyan Chen,Dong-Hau Kuo,Ping Li,Adugna Boke Abdeta,Osman Ahmed Zelekew,Jinguo Lin,Xiaoyun Chen
A novel and nonstoichiometric Mn1–xMo(S,O)4–y oxysulfide catalyst with oxygen vacancies and a partial Mo6+-to-Mo4+ transition after the substitution of sulfur was synthesized for an efficient photocatalytic hydrogen evolution reaction (PHER). With appropriate sulfur substitution, a MnMoO4 semiconductor with a wide band gap was converted to Mn1–xMo(S,O)4–y with a narrow gap and a suitable band position for PHER. MnMo oxysulfide of 50 mg achieved a high PHER rate of 415.8 μmol/h under visible light, an apparent quantum efficiency (AQE) of 4.31% at 420 nm, and a solar-to-hydrogen (STH) conversion efficiency of 1.28%. Oxygen vacancies (VO) surrounded by low coordination metal atoms act as active reaction sites, which strengthen water adsorption and activation. Here, we demonstrate that sulfur substitution of MnMoO4 for lowering its wide band gap can not only disturb the strict periodicity of the lattice but also the valence states of Mn and Mo for enhancing PHER via material design.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Energy Storage
·
2022
·
IF 8.907
Ying Xue,Zhengjie Xie,Xilong Liu,Liangyu Liu,Yixin Li,Yingjie Hua,Xudong Zhao,Xiaoyang Liu
Hierarchical core-shell heterostructured NiCo 2 O 4 @MnMoO 4 nanosheet hybrid arrays were successfully synthesized on nickel foam via a facile two-step hydrothermal reaction followed by a calcination process. The highly porous hierarchical core-shell heterostructure was fabricated by preforming a NiCo 2 O 4 nanosheet “core” as a substrate and then guiding the ultrathin MnMoO 4 nanosheet “shell” onto its surface. The growth thickness of ultrathin MnMoO 4 nanosheets was controlled by adjusting the hydrothermal reaction time. The optimized core-shell heterostructured NiCo 2 O 4 @MnMoO 4 electrode exhibited a specific capacity of 1205.75 C g −1 at a current density of 1 mA cm −2 in 2 M KOH solution and displayed outstanding cycling stability with a capacity retention rate of 100.49% after 5000 charge-discharge cycles at a current density of 30 mA cm −2 . An asymmetric supercapacitor (ASC) device was assembled using the optimal NiCo 2 O 4 @MnMoO 4 nanosheet hybrid arrays as the positive electrode and activated carbon (AC) as the negative electrode which achieved a maximum energy density of 39.04 W h kg −1 at a power density of 156.86 W kg −1 and retained 34.12 W h kg −1 even at the high power density of 1568.74 W kg −1 . In addition, the ASC device presented an excellent cycling performance, maintaining 95.00% retention of its initial specific capacitance after 10,000 cycles at a current density of 20 mA cm −2 , demonstrating its promising potential in energy storage.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）