查找使用阿拉丁产品的科研文献

Vacancy-rich heterogeneous MnCo2O4.5@NiS electrocatalyst for highly efficient overall water splitting

Xingxing Zhu,Zhengtong Ji,Wubin Wan,Yongfu Zhu,Xingyou Lang,Qing Jiang

Alkaline water electrolysis is regarded as a promising technology for sustainable energy conversion. Spinel oxides have attracted considerable attention as potential catalysts because of their diverse metal valence states. However, achieving the required current densities at low voltages is a challenge due to its limited active sites and suboptimal electron transport. In this study, we present a novel bifunctional catalyst composed of MnCo 2 O 4.5 nanoneedles grown on NiS nanosheets for water electrolysis. Remarkably, MnCo 2 O 4.5 @NiS demonstrates exceptional catalytic activity, requiring 187 and 288 mV to achieve a current density of 100 mA cm −2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. The impressive performance of MnCo 2 O 4.5 @NiS is demonstrated by the lower value of voltage 1.44 V needed to deliver the current density of 10 mA cm −2 , which outperformed the 1.66 V required for a commercial Pt/C||RuO 2 system. Detailed structure analysis and density functional theory (DFT) calculations reveal that the MnCo 2 O 4.5 @NiS heterostructure enhances electron transfer at the interface, promotes the formation of oxygen vacancies and tunes the electronic structures of Mn and Co. These findings underscore the potential of MnCo 2 O 4.5 @NiS as an efficient and cost-effective electrocatalyst for hydrogen production.

Constructing core–shell phosphorus doped MnCo2O4.5@ZIS for efficient photocatalytic hydrogen production from water splitting

Yueru Yan,Yuanyuan Zhao,Yun Lou,Yafei Zhao,Huishan Shang,Yinze Yang,Dan Wang,Bing Zhang

Rational construction of core@shell heterostructured photocatalysts is the key to realize efficient hydrogen production from water splitting attributing to the accelerated photoinduced charges separation/transfer and enhanced light absorption ability. In this work, two-dimensional (2D) ZnIn 2 S 4 (ZIS) nanosheets were in-situ grown on phosphorus doped MnCo 2 O 4.5 (P-MnCo 2 O 4.5 ) nanospheres to construct P-MnCo 2 O 4.5 @ZIS heterostructured photocatalysts for efficient photocatalytic hydrogen production. The optimized 6 wt% P-MnCo 2 O 4.5 @ZIS composite presents remarkable photocatalytic hydrogen evolution rate of 4197 µmol g −1  h −1 (8 times of single ZIS) along with excellent cycling stability, which is comparable to most previous reported ZnIn 2 S 4 -based or even noble-metal involved catalysts. The improved photocatalytic performance is resulted from the distinguished heterostructure and components of P-MnCo 2 O 4.5 @ZIS, in which the close contact interface facilitates the separation/transfer and inhibits the recombination of charges, and the uniform distribution of ZIS nanosheets on P-MnCo 2 O 4.5 increases the active sites and fortifies the light absorption. The present work comes up with a prospective method for establishing core@shell ZIS-based heterostructured photocatalysts for efficient hydrogen generation.

Rich Oxygen Vacancies in Bimetallic MnCo2O4.5 Spheres for Enhancing Lean Methane Catalytic Oxidation

Ke Yang,Chenqi Li,Qinghan Zhu,Haiwang Wang,Jian Qi

Methane is the second most prevalent greenhouse gas after carbon dioxide in global climate change, and catalytic oxidation technology is a very effective way to eliminate methane. However, the high reaction temperature of methane catalytic oxidation is an urgent problem that needs to be solved. In this work, a series of MnCo2O4.5catalysts were prepared using carbon spheres as templates, combined with metal ion adsorption and calcination processes. Excitingly, the catalytic oxidation activity of MnCo2O4.5spherical catalyst with irregular nanoparticles on the surface for lean methane (T90= 395 °C) is higher than that of pure phase Co3O4(T90= 538 °C) and Mo3O4(T90= 581 °C) spherical catalysts and even surpasses most precious metal catalysts. The main reasons are as follows: (1) The spherical core with irregular nanoparticle morphology significantly increases the specific surface area, creating abundant active sites; (2) through the optimized distribution of oxygen vacancies, rapid oxygen migration through this structure can quickly enter the catalytic zone; (3) the hierarchical wall structure expands the interface and provides spatial accommodation for the catalytic process. Meanwhile, the structure of the ball wall further expands the reaction interface, providing sufficient space for the occurrence of reactions. Rich and highly active oxygen vacancies are evenly distributed on the surface and inside of the ball. The extraordinary performance of low-temperature methane combustion catalysts has opened a promising new path, which is expected to inject strong impetus into the global energy transition and environmental protection.

Facile synthesis MnCo2O4.5@C nanospheres modifying PbO2 energy-saving electrode for zinc electrowinning

Xuanbing Wang,Junli Wang,Bohao Yu,Wenhao Jiang,Jinlong Wei,Buming Chen,Ruidong Xu,Linjing Yang

The oxygen evolution reaction kinetics in industrial zinc electrowinning is sluggish, resulting in low electrocatalytic activity and substantial energy expenditure (about one-third of energy was wasted due to the strong polarization effect). Herein, the paper described a core-shell structured MnCo 2 O 4.5 @C modified PbO 2 electrode through the pyrolysis and co-electrodeposition as a promising candidate for zinc electrowinning. As a result, the obtained Pb-0.2%Ag/ α -PbO 2 / β -PbO 2 -MnCo 2 O 4.5 @C composite electrode showed a sandwich-like structure, where Pb-0.2%Ag as a core, α -PbO 2 as a mid-layer, and β -PbO 2 -MnCo 2 O 4.5 @C served as an electrocatalytic layer. It also possessed improved OER catalytic activity , only required 680 mV to achieve a current density of 50 mA cm −2 and a Tafel slope of 216.04 mV dec −1 in an acidic solution containing 50 g L −1 Zn 2+ and 150 g L −1 H 2 SO 4 . The current efficiency increased by 0.7% and the cell voltage reduced by 360 mV as compared to a conventional Pb-0.76%Ag alloy electrode, leading to a remarkable energy-consumption reduction of 283.5 kW h for producing per ton metallic zinc. Furthermore, Pb-0.2%Ag/ α -PbO 2 / β -PbO 2 -MnCo 2 O 4.5 @C exhibited a prolonged service life, which worked about 44 h under an ultra-high current density of 2 A cm −2 . Hence, this paper provides the strategy to design and construct non-precious, high-performance catalyst for electrolysis and other applications.

3D core-shell pistil-like MnCo2O4.5/polyaniline nanocomposites as high performance supercapacitor electrodes

Zhanlei Li,Yanwei Sui,Jiqiu Qi,Fuxiang Wei,Yezeng He,Qingkun Meng,Yaojian Ren,Xuping Zhang,Zhenzhen Zhan,Zhi Sun

In this article, a novel supercapacitor electrode of pistil-like MnCo2O4.5@PANI nanorods supported by nickel foam with enhanced specific capacitance and cycle performance is fabricated through a facile method. Benefiting from the excellent electrical conductivity of the shell material PANI and the short ion transport path and high specific surface area of the MnCo2O4.5 nanorods, the electrode made of MnCo2O4.5@PANI exhibits a large specific capacitance of 1098 F g−1 at a current density of 1 A g−1. In addition, the MnCo2O4.5@PANI electrode also displays a superior cycling stability with 83.2% capacitance retention after 5000 cycles at a high charge/discharge current density of 10 A g−1 and an excellent rate performance of 61.45% at 10 A g−1. These results demonstrate that the prepared MnCo2O4.5@PANI composite electrode material has a great potential for advanced energy conversion and storage equipment.

Rational Construction of MnCo2O4.5 Deposited TiO2 Nanotube Array Heterostructures with Enhanced Photocatalytic Degradation of Tetracycline

Yajun Bi,Jiadong Li,Changchang Dong,Wei Mu,Xiaojun Han

Graphical Clean up, clean up : A new heterostructured photocatalyst, MnCo 2 O 4.5 deposited TiO 2 nanotube arrays, was synthesized via a two-step anodization and chemical bath deposition method. The catalyst exhibited enhanced photocatalytic activity in the degradation of tetracycline under visible light irradiation compared with pure TiO 2 nanotube arrays. A novel type of heterostructured photocatalyst, MnCo 2 O 4.5 deposited TiO 2 nanotube arrays (TNAs), was successfully synthesized via a two-step anodization and chemical bath deposition method. The decoration of MnCo 2 O 4.5 nanoparticles on anatase TNAs significantly enhances its photocatalytic degradation activity of tetracycline (TC). The optimized 140MnCo 2 O 4.5 /TiO 2 nanotube arrays (140 M/TNA) catalyst exhibited the highest photocatalytic degradation of TC with an efficiency of 93.1 % after 2 h illumination. Meanwhile, the material showed good stability after a 5 cycle test. The mechanism of increased activity is attributed to the MnCo 2 O 4.5 /TiO 2 heterostructure, which extends the response range to visible light and promotes electron–hole separation. Further radical capture experiment reveals that . O 2 − is vital as an active species for degrading TC in this system. The photocatalyst obtained via this rational synthesis strategy can effectively remove organic pollutants from waste water under visible light irradiation.

Hierarchical MnO2 nanosheets coated on MnCo2O4.5 nanoneedles as advanced electrode for high-efficient hybrid supercapacitor

He Yunbing,Pan Xuexue,Kuang Liping,Hu Bo,Zha Qinbing,Chen Xinman

The MnCo 2 O 4.5 @MnO 2 composite nanomaterial was successfully designed and synthesized via successive hydrothermal and subsequent calcination methods, in which MnO 2 nanosheets coated on MnCo 2 O 4.5 nanoneedle arrays were directly grown on Ni foam. Compared with pristine MnCo 2 O 4.5 nanoneedle electrode, MnCo 2 O 4.5 @MnO 2 composite electrode exhibits a high specific discharge capacitance of 1155 F g -1 at a current density of 1.43 A g -1 , the capacitance retention of 93.4% after 5000 cycles, and low initial internal resistance of 1.9 Ω. The results reveal that the rational design of MnCo 2 O 4.5 @MnO 2 electrode with such structure and composition is an effective strategy to improve electrochemical performances of MnCo 2 O 4.5 . Due to unique nanostructure and brilliant electrochemical properties of MnCo 2 O 4.5 @MnO 2 electrode, the fabricated hybrid supercapacitor based on MnCo 2 O 4.5 @MnO 2 positive electrode and activated carbon negative electrode delivers the wide operating voltage window of 1.6 V, a capacitance retention of 87.8% after 8000 continuous charge-discharge cycles at a current density of 1.33 A g -1 , the maximum energy density of 40.8 Wh kg -1 at a power density of 263.9 W kg -1 , and highest power density of 1336.6 W kg -1 to achieve an energy density of 24.4 Wh kg -1 . Herein, the designed MnCo 2 O 4.5 @MnO 2 composite is a distinguished candidate material for hybrid supercapacitor.

Nanosheet-assembled porous MnCo2O4.5 microflowers as electrode material for hybrid supercapacitors and lithium-ion batteries

Yafei Liu,Xuming Du,Yi Li,Enhui Bao,Xianglin Ren,Huiyu Chen,Xiaodong Tian,Chunju Xu

Herein, the MnCo 2 O 4.5 microflowers (MFs) assembled by two-dimensional (2D) porous nanosheets were prepared through an initial solvothermal reaction with a subsequent annealing process. In this architecture, many interconnected 2D thin nanosheets were self-assembled together to form a 3D hierarchical MF with plenty of open channels. Such structure endows these MnCo 2 O 4.5 MFs with large specific surface area of 156.85 m 2 /g for energy storage and provides rich ion diffusion pathways for ion transportation, thus the as-prepared MFs can exhibit good overall electrochemical performance in both hybrid supercapacitor (HSC) and lithium-ion battery (LIB). For the utilization in supercapacitor, the MFs deliver a specific capacity of 287.02 C/g at 1 A/g as well as a rate capability with 73.3 % capacity retention at 8 A/g. The energy density of the HSC assembled by MFs and activated carbon can reach up to 30.33 W h kg −1 at 959.35 W kg −1 . When applied as the anode for Li-ion battery, a specific capacity of 1340.8 mA h g −1 at 0.1 A/g and cycling performance with low capacity loss of 0.73 mAh/g per cycle after 200 cycles at 0.5 A/g can be achieved. This work uncovers a repeatable and facile synthetic strategy to prepare transition metal oxides with large specific surface area and good overall electrochemical property.

Regulated synthesis of 3D nano-flower-like MnCo2O4.5 catalytic materials to enhance thermal decomposition of ammonium perchlorate

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.

Novel MnCo2O4.5@manganese sand for efficient degradation of tetracycline through activating peroxymonosulfate: Facile synthesis, adaptable performance and long-term effectiveness

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.

Rational Design of Dodecahedral MnCo2O4.5 Hollowed-Out Nanocages as Efficient Bifunctional Electrocatalysts for Oxygen Reduction and Evolution

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.

Trace Ethanol Concentration Sensor Based on Hollow Microbubble Resonator Modified With MnCo2O4.5

Xiaohui Wang,Wenyao Liu,Huiyu Chen,Wei Li,Rong Wang,Yanru Zhou,Enbo Xing,Jun Tang,Jun Liu