Effect of oxygen vacancy on electronic structure and electrochemical performance of MnMoO4: Computational simulation and experimental verification

2022 ◽  
Author(s):  
Xiaoli Li ◽  
Pengxi Li ◽  
Fangfang Wei ◽  
Xuemin Wang ◽  
Weiwen Han ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Hydrothermal Synthesis ◽  
Oxygen Vacancy ◽  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Experimental Verification ◽  
Reduction Method ◽  
Computational Simulation ◽  
Effect Of Oxygen

Porous nanopetal of MnMoO4 with oxygen vacancy is prepared by hydrothermal synthesis and hydrogenation reduction method. The MnMoO4-OV porous nanopetal has a higher specific surface area together with a more...

Design of ZnMoO4 porous nanosheet with oxygen vacancy as better performance electrode material for supercapacitor

2021 ◽  
Author(s):  
Pengxi Li ◽  
Jiepeng Wang ◽  
Liming Li ◽  
Shili Song ◽  
Xianming Yuan ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Oxygen Vacancy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrode Material ◽  
Reduction Method

ZnMoO4 with oxygen vacancy (ZnMoO4-OV) porous nanosheet was synthesized by hydrothermal synthesis and hydrogenation reduction method. The ZnMoO4-OV porous nan sheet delivers a higher specific surface area together with a...

Effect of oxygen vacancy on electronic structure and optical spectra of SrO crystal

2021 ◽  
Vol 133 ◽  
pp. 105940
Author(s):  
Ru-xi Sun ◽  
Ting-yu Liu ◽  
Chun-yu Shi ◽  
Jia-mei Song ◽  
Kai-li Wu
Keyword(s):  
Electronic Structure ◽  
Oxygen Vacancy ◽  
Optical Spectra ◽  
Effect Of Oxygen

Three-dimensional graphene encapsulated hollow CoSe2-SnSe2 nanoboxes for high performance asymmetric supercapacitors

2022 ◽  
Author(s):  
Kainan Li ◽  
Ke Zheng ◽  
Zhifang Zhang ◽  
Kuan Li ◽  
Ziyao Bian ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Specific Capacity ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Large Specific Surface Area ◽  
Composite Aerogel

Abstract Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g-1 at 0.5 A g-1, good rate capability of 212.7 F g-1 at 10 A g-1, and excellent cycle stability due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g-1 at 1A g-1 and an energy density of 11.89 W h kg-1 at 749.9 W kg-1, as well as a capacitance retention of 91.1% after 3000 cycles. This work provides a new method for preparing electrode material.

scholarly journals Time-Resolved X-ray Operando Observations of Lithiation Gradients across the Cathode Matrix and Individual Oxide Particles during Fast Cycling of a Li-Ion Cell

2021 ◽  
Author(s):  
Tianlong Zheng ◽  
Jing He ◽  
Pingwei Cai ◽  
Xi Liu ◽  
Duojie Wu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Performance ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Carbon Paper ◽  
Free Energy Barrier ◽  
Active Components

Abstract Self-supporting three-dimensional (3D) transition metal electrodes have been considered for designing high-performance non-noble metal oxygen evolution reaction (OER) catalysts owing to their advantages such as binder-free, good mass transfer, and large specific surface area. However, the poor conductivity of ((oxy)hydr)oxides and the difficulty in adjusting their electronic structure limit their application. As an alternative strategy, instead of constituting the array electrode by the active components themselves, we herein report 3D Co(OH)2@MnO2 heterostructure decorated carbon nanoarrays grown directly on carbon paper (Co(OH)2@MnO2-CNAs). This unique structure can not only enhance electrical conductivity but also provide a larger specific surface area, and facilitate electrolyte diffusion and ion transport. The core-shell heterostructured Co(OH)2@MnO2 formed via incorporation with MnO2 facilitates the transition of CoII to CoIII in Co(OH)2 and it increases the storage of oxidative charge in the catalyst, leading to an OER activity with benchmark RuO2 and good stability. Density functional theory calculations suggest that the improved OER performance can be attributed to the formation of the heterojunction structure, resulting in the modulation of the electronic structure of Co atoms and the reduction of the free energy barrier of the rate-determining step for the OER.

Preparation of Nanosize Anatase TiO2 Powders by Hydrothermal Synthesis

2007 ◽  
Vol 336-338 ◽  
pp. 2017-2020 ◽  
Author(s):  
Fan Yong Ran ◽  
Wen Bin Cao ◽  
Yan Hong Li ◽  
Xiao Ning Zhang
Keyword(s):  
Grain Size ◽  
Hydrothermal Synthesis ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Reaction Temperature ◽  
Reaction System ◽  
Anatase Tio2 ◽  
Holding Time ◽  
Precursor Concentration

Nanosize anatase TiO2 powders have been synthesized by hydrothermal synthesis by using technical grade TiOSO4 as precursor and urea as precipitating agent. The initial pressure of the reaction system was set at 6 MPa. Stirring speed was fixed at 300r/min. The reaction system reacted at the temperature ranged from 110 to 150°C for holding 2hrs to 8hrs and the concentration of the precursor was ranged from 0.25M to1.5M. XRD patterns show that the synthesized powders are in the form of anatase phase. Calculated grain size is ranged from 6.7 to 8.9nm by Scherrer method from the line broadening of the (101) diffraction peak of anatase. The specific surface area of the powders synthesized under different conditions is ranged from 124 to 240m2/g. The grain size of the powders increases with the increase of the reaction temperature, holding time and precursor concentration, respectively. The specific surface area decreases with the increase of reaction temperature and holding time, and does not obviously change with the change of precursor concentration when the concentration of the precursor is less than 1M. However, when the concentration is higher than 1M, the specific surface area will decrease quickly with the increase of the precursor concentration. XRD and DSC-TG analysis shows that the synthesized anatase TiO2 will begin to transform to rutile TiO2 at about 840°C. When heated to 1000°C for holding 1h, the anatase powders will transform to rutile completely.

A Simple Hydrothermal Synthesis of Cadmium Sulfide Wrapped on Graphene Nanocomposite for Supercapacitor Applications

2021 ◽  
Vol 21 (12) ◽  
pp. 5835-5845
Author(s):  
Ranjith Balu ◽  
Arivuoli Dakshanamoorthy
Keyword(s):  
Hydrothermal Synthesis ◽  
Specific Surface ◽  
Cadmium Sulfide ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Current Density ◽  
Specific Capacity ◽  
Cds Nanoparticles ◽  
Electrochemical Characteristics

Supercapacitor with high specific capacity is desirable for various energy storage and high powerdensity applications. Though Graphene has been the preferred material for high current density, nanocomposites have been attempted to increase the specific capacitance. Hydrothermal synthesis of cadmium sulfide/graphene (CdS/G) nanocomposite with CdS nanoparticles anchored/decorated over the graphene sheets is reported. The structural studies reveal the hexagonal phase of the prepared materials. The specific surface area (BET) and porosity is found to increase upon nanocomposite formation. The electrochemical characteristics such as cyclic voltammetry (CV), GCD and EIS of the CdS/G nanocomposite have been investigated. The capacitance of CdS/G nanocomposite almost doubled to 248 Fg−1 indicating the enhanced performance of the nanocomposite system and in addition it also showed excellent cycling stability of 74.8 percent after 1000 cycles. The supercapacitor investigated retained the initial energy density after charge-discharge, at 0.5 A/g for 1000 cycles. The graphene nanosheets increased the specific surface area and interfacial electron transfer of the composite material. It enhances the specific capacitance and cyclic stability of the supercapacitor device.

S-doped porous carbon confined SnS nanospheres with enhanced electrochemical performance for sodium-ion batteries

2018 ◽  
Vol 6 (37) ◽  
pp. 18286-18292 ◽  
Author(s):  
Yaping Wang ◽  
Yifang Zhang ◽  
Junrong Shi ◽  
Anqiang Pan ◽  
Feng Jiang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Porous Carbon ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Large Specific Surface Area ◽  
Hollow Nanospheres ◽  
Enhanced Electrochemical Performance

S-doped porous carbon confined SnS hollow nanospheres have a unique structure and large specific surface area and exhibit improved electrochemical performance.

The Hydrothermal Synthesis and Photocatalysis of TiO2 Powders

2011 ◽  
Vol 183-185 ◽  
pp. 2024-2027
Author(s):  
Li Ming Jiang
Keyword(s):  
Photocatalytic Activity ◽  
Hydrothermal Synthesis ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Molecule ◽  
Photocatalytic Performance ◽  
Hydrothermal Conditions ◽  
Anatase Structure

Titania powders were prepared under hydrothermal conditions by employing organic molecule β-cyclodextrin(CD) as template, and characterized by means of TGA、XRD、BET . The effects of the pH on the specific surface area and photocatalytic performance of titania were discussed. The results showed that titania powders were anatase structure;the titania powders with specific surface area up to 216.2 m2g-1 were prepared while the system pH was about 1 , and the powders had the best photocatalytic activity.

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