二氧化锰与二维材料复合应用于超级电容器

现如今世界正面临着与能源相关的一系列问题与挑战,科学家们致力于研究绿色高性能的能量存储器件以适应当前乃至以后长久可持续创新发展的需要。超级电容器作为一种新型的绿色能源储存装置,具有功率密度大、理论比电容高、充放电速度快、循环寿命长、安全性高、环境友好且经济等优点,为人类解决能源危机提出了可能。电极材料是影响超级电容器性能的重要因素。近些年,由于二氧化锰基超级电容器具有理论比电容高、化学稳定性好、环境友好等特点被广泛研究。同时多种二维材料也继石墨烯后被相继用作超级电容器电极材料,具有二维结构特征材料在提高双电层电容器的能量密度、改善赝电容电容器方面发挥着重要作用。实现高比电容和高倍率性能,将二氧化锰与二维材料复合将不失为一个有前景的选择。本文系统介绍了以石墨烯为代表的各类二维材料与二氧化锰复合物在超级电容器中的应用研究,并聚焦于这些二维材料与二氧化锰复合后所展现的优异电化学性能。

简易构筑Bi2Mo3O12@Bi2O2CO3异质结增强光催化脱除NO性能及其转化过程（英文）

电荷分离及转移是影响光催化效率的重要因素之一.本文采用简易的水热焙烧法,设计并构筑了Bi2Mo3O12@Bi2O2CO3(BMO@BOC)异质结,促进了光生载流子的分离与迁移,并优化了异质结构中的BMO与BOC的组分比例,其中BMO@BOC-1样品展现了最高的光催化脱除NO效率(~35%),且具有优异的循环稳定性.SEM与TEM结果表明,BMO@BOC-1样品是由超薄纳米片构成,可以提供丰富的反应活性位点,从而促进光催化反应的发生.HRTEM,XRD及Raman充分证明已成功合成不同组分比例的BMO@BOC异质结.同时, Raman与XPS结果表明, BMO@BOC异质结由Bi, O,C及Mo组成, XPS图谱中拟合峰位置的偏移是由异质结组分不同所致.值得注意的是, UV-visDRS结果表明,BMO@BOC-4具有最好的光谱吸收性能,但它与BMO@BOC-2和BMO@BOC-1样品的吸收带边相近,而PL结果则表明BMO@BOC-1具有更好的电荷分离性能,以及合适的组分比例,在一定程度上可以促进光吸收,并能最大限度的促进光生载流子的分离.BMO@BOC-1样品的ESR测试结果说明,·OH与·O2-的含量随着光照时间的延长而增加,证实了它们是光催化NO氧化的活性中间物种.另外,光催反应机制的研究在高效光催化剂的研发及其商业化应用中具有深远意义.本文还利用原位红外实时动态监测手段,采用"连续流测试法"与"间歇流测试法"直观动态地研究了BMO@BOC异质结催化剂表面光催化NO脱除反应过程.结果表明,在开灯前的吸附阶段于催化剂表面形成了NO-, NO2-以及NO2等中间产物,开灯后的氧化阶段出现终产物(NO3-).进一步深入分析,中间产物NO-和NO2-在氧化阶段会被氧化活性物种进一步氧化成NO3-,而中间产物NO2可能作为一种毒副产物影响NO的完全氧化.综上所述,本文将为理解NO氧化过程提供直观且动态的研究方法,对光催化技术的发展具有重要的指导意义.

Anion intercalated layered-double-hydroxide structure for efficient photocatalytic NO remove

Due to the easily controllable interlayer anions, metal cation composition proportion and thickness, which is beneficial to modify surface chemical state and tune bandgap, layered double hydroxides(LDHs) have great promising potential for photocatalytic applications. In this study,we have successfully synthesized the ZnAl–LDH intercalated the single anion between ZnAl cationic interlayer without anionic impurities by using a facile calcining and reconstructing routes. The electron structure and surface chemical state of the prepared products have been investigated by combining the DFT calculation and experimental characterization methods. UV–vis DRS was used to certify the light absorption of the prepared products, and we performed the DFT calculation to demonstrate the density of state and activation of reactant. These results suggested that the ZnAl–LDH–CO3 possessed the more proper band structure and superior ability to activate NO and O2 for accelerating the photocatalytic NO oxidation activity. Moreover, the in situ DRIFTS with dynamically monitoring intermediates and products over the ZnAl–LDH–CO3 was adopted to declare the photocatalytic NO oxidized process during the photocatalytic reaction process. This work illustrated the influence of different interlayer anions to the electron structure and surface chemical state of ZnAl–LDH structure through the experimental verification combined DFT calculation and the photocatalytic NO oxidized process via in situ DRIFTS analyzing, which would provide a novel way to design and fabricate the efficient photocatalysis, and understand the reaction process.

Compulsive malposition of birnessite slab in 2D-Parallel birnessite on β-MnO_(2) networks for enhanced pseudocapacitance performances

High electrochemically active bimessite is always desirable pseudocapacitive material for supercapacitor.Here,two-dimensional(2D)compulsive malposition parallel bimessite standing on β-MnO_(2) interconnected networks have been designed.Due to the retrition of β-MnO_(2),compulsi ve malposition,slippage of MnO6 slab,occured in bimessite resulting in weaken bi nding force between bimessi te slab and interlayer cations,which enhanced their electrochemical performances.Additionally,the electrical conductivity of the structure was largely promoted by the 2D charge transfer route and double-exchange mechanism in bimessite,also leading to desirable electro-chemical properties.Based on the fraction of as-prepared nanostructure,the par all bimessite exhibited good pseudocapacitance performance(660 F g^(-1))with high rate capability.In addition,the asymmetrice supercapacitor assembled by reduced graphene oxide(RGO)and as-prepared nanostructure,which respectively served as the negative and positive eletrode,delivered an energy density of 33.1 Wh kg^(-1) and a mad mum power density of 64.0 kW kg^(-1) with excellent cyeling stability(95.8% after 10000 cycles).Finally,the study opens new avenwes for synthesizing high eletrochemically actiwe bimessite structure for high-performance energy storage devices.

Melamine sponge derived porous carbon monoliths with NiMn oxides for high performance supercapacitor

Supercapacitors with good electrochemical performance and flexibility are in great demand.In this paper,the concept of preparing 3D porous carbon monoliths via direct calcination of melamine sponge is presented.This preparation method is simple and has good control of the structure.Porous carbon composite nickel-manga nese oxides can be obtained by hydrothermal method followed with calcination.The electrochemical performances were tested and porous carbon monoliths with NiMn oxides exhibited a specific capacitance of 870 F/g in 1 mol/L KOH at a charge/discharge current density of 0.5 A/g and a capacity retention of 89.9% after 5000 times charge and discharge.