Advanced Energy Materials
·
2018
·Vol. 8
·期 34
·1802390
·
IF 21.875
Zhengyu Bai,Jinmeng Heng,Qing Zhang,Lin Yang,Fangfang Chang
Efficient bifunctional electrocatalysts are in demand to increase kinetics of oxygen reduction and evolution reactions (ORR and OER) for rechargeable zinc–air batteries. In this work, dodecahedral MnCo 2 O 4.5 hollowed-out nanocages are synthesized using a seed-mediated coordination chemistry of metal–organic frameworks. The hollowed-out MnCo 2 O 4.5 nanocages used as bifunctional oxygen electrocatalysts exhibit high catalytic activity and excellent stability for both ORR and OER in alkaline media, which can be attributed to both the hierarchical porosity and stable hollowed-out structure that not only facilitate fast charge transfer reaction but also prevent the agglomeration of MnCo 2 O 4.5 nanoparticles. The dodecahedral hollowed-out MnCo 2 O 4.5 nanocages as the air electrode catalyst can deliver good stability in a rechargeable zinc–air battery. Scanning electron microscopy and transmission electron microscopy images, X-ray diffraction and X-ray photoelectron spectroscopy of the electrocatalyst were measured again after durability tests. There is no significant influence on the morphologies, compositions, and structures before and after durability tests.
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高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Tianyang Liu,Junli Wang,Xuanbing Wang,Jinlong Wei,Xiaoning Tong,Shengyou Su,Ju Zhang,Yuantao Yang,Ruidong Xu,Linjing Yang
The traditional Pb-Ag anodes used in zinc electrowinning exhibit high overpotential for oxygen evolution reaction (OER) and poor mechanical strength, leading to high energy consumption. To overcome the shortcomings, Ti/SnO 2 -Sb 2 O 4 /PbO 2 -La-doped MnCo 2 O 4.5 composite anode was prepared by this work. It demonstrated enhanced electrochemical performance, requiring 565 mV to reach the benchmark current density of 50 mA cm −2 , and the Tafel slop of 179.79 mV dec –1 in the acidic media containing 50 g L –1 Zn 2+ and 150 g L –1 H 2 SO 4 . According to the results of XPS, the content of Mn 4+ and Co 3+ increased, which was beneficial to promote the OER catalytic activity of the electrode. The current efficiency was improved by 1.7 % compared with traditional Pb-0.76 % Ag anode, resulting in a significant reduction in energy consumption of 477.46 kW∙h for producing one ton of zinc. Moreover, the Ti/SnO 2 -Sb 2 O 4 /PbO 2 -La-doped MnCo 2 O 4.5 anode showed excellent corrosion resistance, and the accelerated service time was extended to 50 h at 2 A cm −2 . The service life of the electrode was extended thanks to the introduction of the intermediate layer and La-doped MnCo 2 O 4.5 powder. Therefore, this work provided a novel strategy to prepare the anodes with enhanced electrochemical performance applied in zinc electrowinning and other aspects.
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高影响因子
FUEL
·
2024
·
IF 6.7
Xin Yu,Zhengyi Zhao,Guofei Zhang,Sirong Li,Yanzhi Yang,Zhiyong Yan,Xin Tian,Xuechun Xiao
In this study, a one-step preparation of carbon-rich MnCo 2 O 4.5 precursors are achieved by adding glucose in a hydrothermal environment. Subsequently, MnCo 2 O 4.5 catalytic materials with different carbon defect contents are obtained by controlling the calcination temperature, which enables the simultaneous release of great heat during the thermal decomposition of catalytic AP. This specially designed MnCo 2 O 4.5 catalytic material has a hollow structure and exhibits good dispersion and a large specific surface area. The high-temperature decomposition temperature ( T HTD ) of ammonium perchlorate (AP) is reduced from 473.48 ℃ to 301.32 ℃ after adding 2 wt% catalytic materials. The catalytic materials resulte in a threefold increase in the decomposition heat release of AP (from 888.26 J·g −1 to 2616.98 J·g −1 ). It also reduced the activation energy ( E a ) by half, from 296.8 kJ·mol −1 to 146.2 kJ·mol −1 , greatly facilitating the reaction. Consequently, the reaction rate ( k ) is doubled, from 0.44 s −1 to 0.97 s −1 . The bimetallic synergistic effect of MnCo 2 O 4.5 itself, combined with the carbon material, significantly improved its performance in catalysing the thermal decomposition of AP. In addition, the combustion of carbon materials not only provides additional heat for AP pyrolysis but also further enhances the combustion of the Hydroxy Terminated Polybutadiene Composite Solid Propellant (HTPB-CSP) system. The introduction of this catalytic material reduces the CSP ignition delay time by 13 ms, allowing for a faster and more intense combustion process.
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高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Xin Yu,Zhengyi Zhao,Guofei Zhang,Songnan Qin,Sirong Li,Zhenlong Wang,Ying Hu,Xuechun Xiao
Morphological control enables precise modulation of the specific surface area, pore structure, and crystal structure of catalytic materials, thereby enhancing catalytic efficiency. In this study, morphology controlled synthesis of MnCo 2 O 4.5 samples was achieved by solvent-hydrothermal method by varying the ethylene glycol to deionized water volume ratio. The 3D nano-flake-like MnCo 2 O 4.5 material with a larger specific surface area was successfully prepared at a volume ethylene glycol to deionized water (6:40). The ammonium perchlorate (AP) is high temperature decomposition (HTD) peak temperature decreases from 473.48 °C of pure AP to 304.39 °C and the heat release increases from 888.26 J g −1 to 2094.50 J g −1 after the addition of 2.0 % 3D nano-flower-like MnCo 2 O 4.5 . The activation energy ( E a ) goes down to 89.2 kJ mol −1 relative to pure AP (296.8 kJ mol −1 ). When applied to Hydroxy-terminated polybutadiene composite solid propellant (HTPB-CSP), the combustion process of HTPB-CSP containing 3D nano-flower-like MnCo 2 O 4.5 is more intense compared with only containing pure AP. The time to achieve the maximal combustion effect is accelerated from 390 ms to 268 ms, and the ignition delay time is lowered from 35 ms to 23 ms. Based on its microstructural design and optimization, MnCo 2 O 4.5 has a remarkable catalytic performance for AP thermal decomposition, according to the experimental results.
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高影响因子
Nanomaterials
·
2026
·Vol. 16
·期 4
·252
·
IF 4.8
Bo Kou,Bowei Gao,Xianliang Chen,Wei Chen,Linghua Tan
Enhanced catalytic activity for composite solid propellants (CSPs) can be achieved through high-efficiency dispersion of active sites on the surface of two-dimensional (2D) materials. In this study, we report the in situ formation of MnCo2O4.5nanoneedles on the surface of covalent triazine frameworks (CTFs), resulting in 2D CTF/MnCo2O4.5composites with outstanding catalytic properties for the thermal decomposition of ammonium perchlorate (AP). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the successful preparation of the CTF/MnCo2O4.5composites and revealed the interaction between CTFs and MnCo2O4.5. Scanning electron microscopy (SEM) and elemental mapping further demonstrated the uniform anchoring and dispersion of MnCo2O4.5nanoneedles on the layered CTF surfaces. Additionally, the obtained CTF/MnCo2O4.5composites exhibited promising catalytic capacity for AP decomposition. When added at a loading of 2 wt%, the CTF/MnCo2O4.5composites significantly reduced the thermal decomposition temperature of AP by 81.3 °C, while simultaneously decreasing the content to 30 wt% compared to pure MnCo2O4.5catalysts.
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DOI
PubMed
高影响因子
Sustainable Materials and Technologies
·
2023
·
IF 9.6
Han Chen,Tiange Gao,Mingxia Wu,Xuefei Wei,Anbao Yuan,Jiaqiang Xu
Transition metal oxides or selenides have been widely used in electrode materials for supercapacitors. And the formation of heterostructures between the two different materials can further realize high-performance electrode materials and high-energy density supercapacitor. Therefore, in our work, the novel reaction method of incomplete selenization makes the electrode material have both oxides and selenides, and the prepared heterostructured composite material has excellent electrochemical performance. Herein, the nickel foam (NF)-supported flower-shaped manganese‑cobalt-oxide-selenide composite heterostructures self-assembled from the heterogeneous nanorods consisting of MnCo 2 O 4.5 , CoSe, and MnSe 2 components were designed and fabricated via a facile, adjustable, incomplete selenization of the hydrothermal derived manganese‑cobalt hydroxide (Mn-Co-OH) precursor (named as Mn-Co-O-Se-x, where x represents the feed mass ratio between selenium powder and precursor, which is 5, 10, and 20, respectively). The optimized Mn-Co-O-Se-5 composite exhibits a high specific capacitance of 3424 F g −1 at a current density of 1 A g −1 . After 10,000 cycles at 20 A g −1 , the discharge capacitance is 103.7% of the first value, demonstrating superior cycle stability. Moreover, the assembled Mn-Co-O-Se-5//activated carbon (AC) asymmetric supercapacitor (ASC) device delivers maximum energy density and power density at 112 Wh kg −1 and 16,000 W kg −1 and shows good cycling stability with a capacitance retention of 98.7% after 10,000 cycles at 10 A g −1 , demonstrating promising prospects for application in supercapacitors.
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Yingjie Zhang,Qian Peng,Wanling Zhong,Jiajie Xing,Kun Liu
Mn-Co bimetallic oxides@manganese sand (MC@MS) was successfully synthesized and used as a heterogeneous peroxymonosulfate (PMS) activator for the first time. The relationship between catalyst performance and preparation conditions was discussed, and 450–1.5MC@MS exhibited superior performance. 450–1.5MC@MS had excellent adaptability to the treatment conditions, and it was further confirmed that HPO 4 2− could significantly improve the utilization of PMS in the system thus promoting tetracycline (TC) degradation. In addition, 450–1.5MC@MS possessed superior stability, with only a 15.7% decrease in TC degradation efficiency after five cycles. Moreover, the catalytic activity of 450–1.5MC@MS could be easily recovered to that of the first round basically by calcination at 300 ℃. More importantly, the continuous-flow column reaction experiments showed that 450–1.5MC@MS had excellent working life, only 15 g catalyst could continuously treat 13.5 L TC solution with an acceptable removal efficiency. MS can also promote PMS activation due to the participation of Mn(II)/Mn(III)/Mn(IV) redox cycle. Besides, sulfate radicals (SO 4 • − ) and singlet oxygen radicals ( 1 O 2 ) were identified as the predominant reactive oxygen species driving TC degradation. In brief, this study reports a novel and environmentally friendly catalyst that has great application potential for the treatment of organic wastewater.
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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2023
·Vol. 170
·期 11
·112504
·
IF 3.9
Xiaocong Zhong,Yahui Ren,Huai Jiang,Kuifang Zhang,Ruixiang Wang,Zhifeng Xu,Boyi Xie,Shuiping Zhong
Based on the outstanding catalytic activity and stability of Mn-Co bimetallic oxides toward oxygen evolution in acidic solutions, MnCo2O4.5 was incorporated into a Pb matrix through a powder pressing-sintering process to obtain a Pb-MnCo2O4.5 composite anode. The results show that compared with the Pb anode that was made via the powder pressing-sintering process (PS-Pb), the oxide layer formed on the Pb-MnCo2O4.5 anode presented a higher flatness, compactness, and β-PbO2 concentration. Consequently, Pb-5.0MnCo2O4.5 presented a stable anodic potential of 1.235 V, approximately 170 mV lower than that of the PS-Pb anode. In the case of lower MnCo2O4.5 content (≤2.5%), the Pb-MnCo2O4.5 composite anode exhibited a smaller Tafel slope (70.39 ∼ 79.59 mV dec−1) and a lower charge transfer resistance (0.437 ∼ 0.676 Ω cm2). The fresh Pb-5.0MnCo2O4.5 composite anode showed a self-corrosion density of 0.25 mA cm−2, approximately 14.3% of that tested on the PS-Pb anode. However, Co2+ and Mn2+ were detected in the electrolyte during 72 h of electrowinning with the Pb-MnCo2O4.5 composite anode. In summary, the Pb-MnCo2O4.5 composite anode has the potential to reduce the energy consumption of the metal-electrowinning process. Nonetheless, it is necessary to evaluate the influence of dissolved Co2+ and Mn2+ on the cathodic process before commercial application.
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高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
·
IF 3.5
Xin Yu,Zhengyi Zhao,Guofei Zhang,Sirong Li,Songnan Qin,Yanzhi Yang,Zhiyong Yan,Yuhan Yang,Xuechun Xiao
This study systematically investigates the relationship between the solvent used, the crystal morphology of MnCo 2 O 4.5 , and its thermocatalytic activity using the solvent thermal method. By tweaking the urea content in the solvothermal process and the ethanol/glycol ratio in the reaction solvents, the shape and size of the MnCo 2 O 4.5 precursor were controlled by altering the crystal growth direction and rate. The MnCo 2 O 4.5 material with “litchi” core-shell structure with maximum specific surface area and abundant pore structure is prepared when the addition amount of urea is 27 mmol and the solvent is ethanol/glycol (20:40 mL). This material reduces the high thermal decomposition temperature ( T HTD ) of ammonium perchlorate (AP) from 473.48 °C to 274.86 °C and increases the exothermic amount from 888.26 J g −1 to 1654.03 J g −1 . Compared to pure AP (296.8 kJ mol −1 ), the activation energy ( E a ) of AP + 2.0 wt% MnCo 2 O 4.5 catalytic material decreases to 61.1 kJ mol −1 . Applying the “litchi” core-shell structured MnCo 2 O 4.5 to the hydroxyl-terminated polybutadiene composite solid propellant (HTPB-CSP) enhances combustion intensity, reducing the time to peak combustion from 390 ms for pure AP to 265 ms and ignition delay from 35 ms to 21 ms. The experimental results indicate that the “litchi” MnCo 2 O 4.5 boosts AP thermal decomposition and improves HTPB-CSP combustion.
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高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Zilong Zheng,Wenchao Zhang,Liang Chen,Wenhui Xiong,Guowei Zeng,Jiaqi Liu,Runhui Wu,Jiaxin Wang,Jiahai Ye,Junwu Zhu
In this work, ternary transition metal oxides MnCo 2 O 4.5 nanosheets was anchored on reduced graphene oxide (RGO/MnCo 2 O 4.5 NSs) in an in-situ way for catalyzing ammonium perchlorate (AP). XRD , FT-IR, Raman, EDX, XPS , SEM, TEM , HR-TEM, SAED and nitrogen absorption-desorption techniques were applied to characterize the structure and morphology of the catalyst. The catalytic performances for the thermal decomposition of AP were investigated using DSC and TG. The results show that the MnCo 2 O 4.5 nanosheets are vertically grown on RGO sheets to form a hierarchically porous structure, which is remarkably effective to avoid both the aggregation of MnCo 2 O 4.5 NSs and the re-stacking of RGO. The introduction of RGO will significantly lead to an increase in conductivity and specific surface area. Just for that reason and the synergetic effect between RGO and MnCo 2 O 4.5 NSs, the synthesized RGO/MnCo 2 O 4.5 NSs composites gets the low-temperature decomposition peak of AP disappeared, the high-temperature decomposition temperature reduced by as high as 124.1 °C, the activation energy decreased from 221.04 to 129.85 kJ·mol −1 , and the reaction rate increased incredibly up to 186.8 times when compared with corresponding data of the pure AP. Furthermore, the catalytic mechanism of the RGO/MnCo 2 O 4.5 NSs has been discussed either based upon the electron-transfer theory.
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高影响因子
危险品化学品经营许可证（带存储）