电化学法制备石墨烯/镍钴氧化物复合薄膜电极及其性能

用电化学法控电位制备石墨烯/Co₂O₃-NiO薄膜电极,通过XRD、Raman、SEM、TEM等仪器对所制备的薄膜进行表征。复合材料中Ni和Co主要以NiO和Co₂O₃的形式负载于石墨烯的表面,直径在50~200 nm之间。循环伏安测试结果表明,石墨烯/Co₂O₃-NiO复合材料性能较纯石墨烯材料明显提升。恒电流充放电测试表明,石墨烯/Co₂O₃-NiO复合材料具有高比电容,在2 A/g的电流密度下,复合材料的比电容最高达到503 F/g,循环500次后比电容保持率为91%。     

空气氛围下废弃秸秆转化为铁/生物碳复合储能材料的研究

采用熔融盐法通过向秸秆材料中掺杂铁元素，将废弃秸秆转化为铁氧化物/生物碳储能材料(FeBNS)。研究了铁加入量对FeBNS储能性能的影响，并对其进行结构表征和电化学性能测试。结果表明，碳基材料中的铁氧化物主要以Fe₂O₃和Fe₃O₄的形式存在，FeBNS呈现出明显的片状结构，并且具有丰富的孔道结构。成功制备了具有双电层电容和赝电容性质的超级电容材料，在电流密度为2 A/g时，电容为212.2 F/g;电流密度为10 A/g时，电容为149.9 F/g,保留率为70.6%。     

介孔CoMn2O4/还原氧化石墨烯复合材料的制备及其超级电容性能

采用共沉淀法制备了CoMn₂O₄/还原氧化石墨烯(CoMn₂O₄/rGO)复合电极材料,并研究了石墨烯含量对CoMn₂O₄/rGO复合材料形貌、微观结构及电化学性能的影响。结果表明:CoMn₂O₄纳米颗粒沉积在石墨烯纳米片的表面,随着石墨烯含量的增加,CoMn₂O₄纳米颗粒在r GO表面的分布逐渐均匀,聚集现象消失。CoMn₂O₄/rGO具有高的比表面积及优良的电化学性能,其中CoMn₂O₄/rGO20 (rGO质量分数为20%)电容性能最好,在电流密度1 A/g时具有1 420 F/g的比电容。CoMn₂O₄/rGO30(rGO质量分数为30%)的倍率性能和循环稳定性能最好。2 000次充放电后,样品CoMn₂O₄/rGO30在5 A/g时的比电容保持率为94%,样品CoMn₂O₄的比电容保持率为78%。     

Co3O4@MnO2空心核壳材料的制备及电容性能研究

以二甲基咪唑和六水硝酸钴为原料合成ZIF-67,采用水热法在ZIF-67表面生长MnO₂纳米片,经热处理获得空心Co₃O₄@MnO₂核壳材料。表面网状纳米片具有更多的活性位点,同时为电解液渗透提供扩散通道,空心材料的薄壁提高了电子的迁移效率。电容性能测试结果表明,Co₃O₄@MnO₂/泡沫镍（Co₃O₄@MnO₂/NF）电极在0.5 A/g电流密度下容量达到278.3 F/g,高于ZIF-67/NF电极（53.7 F/g）和ZIF-67@MnO₂/NF电极（192.8 F/g）;循环5 000次后容量仍保持了最大值的80.5%,具有优异的稳定性。     

生物质焦油衍生氮掺杂多孔碳负载Co3O4纳米晶的制备及双功能氧反应催化

以生物质焦油活化多级孔碳为骨架,通过一步水热合成同时实现氮掺杂和Co₃O₄纳米粒子负载,获得Co₃O₄@N/C复合催化剂。对比研究结果表明,凭借复合材料中活性Co₃O₄和N掺杂结构之间的协同效应,Co₃O₄@N/C复合催化剂对氧还原（ORR）和析氧反应（OER）均表现出较高的催化活性,ORR和OER启动电位电势差ΔE为0.99V;其中,ORR极限扩散电流密度为-5.10mA/cm²,与贵金属Pt/C相当。此外,Co₃O₄@N/C具有优异的氧还原稳定性,在经3000次循环伏安法扫描后,Co₃O₄@N/C的极限扩散电流密度仍能保持89.9%。这一生物质焦油衍生碳所构筑的N掺杂多孔碳负载Co₃O₄纳米晶复合材料在燃料电池和金属空气电池等领域具有巨大的应用潜力。     

磁性固体酸催化剂Fe3O4/C-SO3H制备及表征

以四氧化三铁为磁核,生物质碳（葡萄糖、淀粉、蔗糖）为原料,采用先制备Fe₃O₄/C,再对其进行磺化的方法制备磁性碳基固体酸催化剂Fe₃O₄/C-SO₃H。以辛基葡萄糖苷的合成反应为探针,考察生物质碳种类、碳化温度、碳化时间、酸种类、磺化温度和磺化时间等因素对葡萄糖转化率和催化剂酸含量的影响。利用FT-IR、XRD、TG、SEM和振动样品磁强计（简称VSM）等对催化剂进行表征。结果表明Fe₃O₄/C-SO₃H的最佳制备条件为：以淀粉为生物质碳源,其用量为m（Fe₃O₄）∶m（淀粉）=1∶10,碳化温度为190℃,碳化时间为8 h,以对甲苯磺酸为磺酸源,其质量比为m（Fe₃O₄/C）∶m（对甲苯磺酸）=1∶0.6,磺化温度为250℃,磺化时间为4 h。在上述条件下,催化剂酸含量为1.17 mmol/g,葡萄糖转化率为97.9%。表...     

等离子体辅助快速合成磁性Fe3O4/NaA复合材料及其CO2吸附性能

吸附法是捕集分离CO₂等温室气体的重要方法,磁性复合材料能实现气固相快速分离而备受关注。本文利用介质阻挡放电等离子体处理方法,分别对磁性Fe₃O₄和分子筛前体进行处理,再通过水热法快速制备了Fe₃O₄/NaA复合材料。利用X射线衍射、红外光谱、扫描电镜和元素扫描等技术进行了表征,并考察了复合材料中Fe₃O₄/NaA含量比对CO₂吸附性能和磁性能的影响。结果显示,当Fe₃O₄的质量分数为23.2％时,Fe₃O₄/NaA复合材料既具有优异CO₂吸附能力（2.10mmol/g）,又具有较好的磁性（25.92emu/g）,同时CO₂吸附-脱附循环稳定性高,是一种新型磁性CO₂吸附剂。在采用流化床吸附捕集CO₂技术中,有望实现气固高效磁分离。     

氮掺杂石墨烯/碳纳米管/无定形炭复合材料制备及其电化学性能

碳基复合材料被认为是超级电容器广泛应用最有前景的电极材料之一。本文使用氧化石墨烯（GO）、硝酸钴［Co(NO₃)₂］、三聚氰胺为原料,利用钴对高温下热解碳源的催化作用,制备得到了氮掺杂石墨烯/碳纳米管/无定形炭（NC）复合材料,并测试了其电化学性能。探究了金属和三聚氰胺添加量对碳基复合材料结构和性能的影响,研究发现,在添加量分别为0.02mmol和0.3g时,制得的样品具有大比表面积（380.5m²/g）和高掺氮质量分数（6.29%）,并在三电极系统中体现出优异的电化学性能,电流密度为0.5A/g时样品的比电容为137.1F/g,5A/g时比电容为113.5F/g,保持率为88.5%,具有优异的倍率性能,在循环5000圈后样品的容量保持率为104%,具有良好的循环稳定性,这归因于三维结构可以加快充放电过程中的离子转移和氮掺杂可提高材料润湿性和贡献部分赝电容,为超级电容器电极材料的制备提供了理论借鉴。     

Fe3O4@TRGO的制备及储锂性能研究

本文采用Fe³⁺对氧化石墨烯(GO)进行交联所获得的产物进行热还原生成的热还原石墨烯包裹Fe₃O₄结构(Fe₃O₄@TRGO)。采用透射电镜(TEM)、X射线衍射(XRD)等测试手段表征其的组成与形貌。并研究了Fe₃O₄@TRGO作为锂离子电池负极的储锂性能。热还原石墨烯在电池循环过程中抑制了Fe₃O₄的体积膨胀,其三维结构提高了电子传输速率。拥有良好的电化学性能(在0.1A/g电流密度下,循环120次后放电比容量为775.06mAh/g),且在大电流密度下也保持良好的性能(1A/g电流密度下循环110圈后容量为592.49mAh/g)。     

DMFC阳极催化剂用GRQD-NiCo2O4复合物的制备与电催化活性分析

采用水热法制备GRQD-NiCo₂O₄复合物,利用XRD、SEM及TEM分析其微结构,并探讨其作为DMFC阳极催化剂使用时的电化学性能。微结构分析表明所得GRQD-NiCo₂O₄复合物皆为具NiCo₂O₄单一相的尖晶石结构,且GRQD质量浓度高于0.25 g/mL后表面形貌将转变GRQD与NiCo₂O₄相互结合的状态。电化学分析表明添加GRQD可有效增强NiCo₂O₄的导电性并提升其电化学稳定性,其中GRQD质量浓度为0.25 g/mL时所得样品经500次循环测试后电流密度约为77.5 A/g,与循环5次后相比其电流密度剩余量最大（约为69.7%）,该样品作为DMFC阳极催化剂使用时性价比最佳。     

NiCo2O4@quinone-rich N–C core–shell nanowires as composite electrode for electric double layer capacitor

The bind-free carbon cloth-supported electrodes hold the promises for high-performance electrochemical capacitors with high specific capacitance and good cyclic stability. Considering the close connection between their performance and the amount of carbon material loaded on the electrodes, in this work, NiCo₂O₄ nanowires were firstly grown on the substrate of active carbon cloth to provide the necessary surface area in the longitudinal direction. Then, the quinone-rich nitrogen-doped carbon shell structure was formed around NiCo₂O₄ nanowires, and the obtained composite was used as electrode for electric double layer capacitor. The results showed that the composite electrode displayed an area-specific capacitance of 1794 mF∙cm^–2 at the current density of 1 mA∙cm^–2. The assembled symmetric electric double layer capacitor achieved a high energy density of 6.55 mW∙h∙cm^–3 at a power density of 180 mW∙cm^–3. The assembled symmetric capacitor exhibited a capacitance retention of 88.96% after 10000 charge/discharge cycles at the current density of 20 mA∙cm^–2. These results indicated the potentials in the preparation of the carbon electrode materials with high energy density and good cycling stability.     

多孔竹炭负载SnO2的制备及其电化学性能研究

多孔竹炭为无定形碳,具有丰富的孔结构,孔径分布在1~6 nm之间,且具有较大的孔体积(1.21 cm³/g)。本文以多孔竹炭为载体,采用溶胶-凝胶法制得B₂O₃-SnO₂/C复合材料。SEM和TEM结果显示SnO₂和B₂O₃均匀分布在多孔竹炭表面。多孔竹炭和B₂O₃有效缓冲SnO₂可逆反应的体积变化,提高SnO₂的循环稳定性。将B₂O₃-SnO₂/C复合材料作为负极组装成锂离子半电池,进行电化学性能测试,在1 C(1 C=372 mA/g)倍率下充放电循环200次结束后仍然保留649.9 mAh/g的放电比容量,放电比容量保留率为58.6%。B₂O₃-SnO₂/C复合材料充放电过程受扩散和电容两种行为控制,电容控制的贡献率随着扫描速率的增大而增大。     

Construction of free binder V2O5 and Fe2O3 flexible electrode and its application in supercapacitor

In recent years, more and more research has been devoted to the development of new electrode materials with ultra-high energy density and high Faraday reaction activity, especially applying them to a new generation of supercapacitor energy storage systems. In this study, sea urchin-shaped V₂O₅ nanospheres and tetrakaidecahedron Fe₂O₃ nano boxes have been grown directly on flexible matrix carbon cloth by hydrothermal method. The hydrothermal time can control the microstructure of V₂O₅, and the morphology determines the performance of energy storage, the positive electrode material of sea urchin-shaped V₂O₅ nanosphere exhibits a maximum specific capacitance of 535 F·g^-1. In addition, the tetrakaidecahedron Fe₂O₃ nano box is used as the negative electrode, and a new structure V₂O₅//Fe₂O₃ flexible supercapacitor is assembled. When the power density is 699.49 W·kg^-1, the energy density can reach 46.06 W·h·kg^-1. Moreover, it also has good mechanical flexibility, and the specific capacity retention rate is still as high as 83.4% after 5000 times of 180° bending cycle tests. This work provides a general and effective strategy for developing the next generation flexible electronic devices with ultra-high energy density.     

免黏结剂V2O5和Fe2O3柔性电极的构建及在超级电容器中的应用

近年来,越来越多的研究致力于开发新型、超高能量密度、高法拉第反应活性的电极材料,尤其将其应用于新一代超级电容器储能系统。通过水热法直接在柔性基质碳布上生长海胆状V₂O₅纳米球和十四面体Fe₂O₃纳米盒子。V₂O₅微观结构和储能性能可通过改变水热时间进行调控。海胆状V₂O₅纳米球正极材料具有最高比容量535 F·g^-1。以十四面体Fe₂O₃纳米盒子作为负极材料组装的新型结构V₂O₅-CC//Fe₂O₃-CC柔性超级电容器,在功率密度为699.49 W·kg^-1时,能量密度可达46.06 W·h·kg^-1。而且具有良好的机械柔韧性,在180°弯曲循环测试5000次,比容量保持率仍高达83.4%。研究为开发下一代超高能量密度、柔性电子器件提供了一种通用而有效的策略。     

Engineering the grain boundary: a promising strategy to configure NiCoP4O12/NiCoP nanowire arrays for ultra-stable supercapacitor

NiCoP₄O₁₂/NiCoP nanorod-like arrays with tunable grain boundary density and pores were synthesized by the processes composed of hydrothermal and pyrolysis, in which, the electron structure of Ni and Co atoms characterized by X-ray photoelectron spectroscopy was contemporaneous inverse manipulated. The optimized NiCoP₄O₁₂/NiCoP arrays have a high specific capacitance of 507.8 μAh∙cm^–2 at 1 mA∙cm^–2, and good rate ability of 64.7% retention at 30-folds increased current density. Importantly, an ultra-stable ability, 88.5% of retention after 10000 cycles, was achieved in an asymmetric cell assembled of the NiCoP₄O₁₂/NiCoP arrays with activated carbon. In addition, the energy and power densities of an asymmetric cell were higher than those of other work, demonstrating as-prepared NiCoP₄O₁₂/NiCoP arrays are promising electrodes for supercapacitors.     

Ethylene dimerization over NiSO4 supported on Fe2O3-promoted ZrO2 catalyst

The NiSO₄ supported on Fe₂O₃-promoted ZrO₂ catalysts were prepared by the impregnation method. Fe₂O₃-promoted ZrO₂ was prepared by the coprecipitation method using a mixed aqueous solution of zirconium oxychloride and iron nitrate solution followed by adding an aqueous ammonia solution. No diffraction line of nickel sulfate was observed up to 20 wt.%, indicating good dispersion of nickel sulfate on the surface of Fe₂O₃–ZrO₂. The addition of nickel sulfate (or Fe₂O₃) to ZrO₂ shifted the phase transition of ZrO₂ (from amorphous to tetragonal) to higher temperatures because of the interaction between nickel sulfate (or Fe₂O₃) and ZrO₂. 15-NiSO₄/5-Fe₂O₃–ZrO₂ containing 15 wt.% NiSO₄ and 5 mol% Fe₂O₃, and calcined at 500 °C exhibited a maximum catalytic activity for ethylene dimerization. NiSO₄/Fe₂O₃–ZrO₂ catalysts was very effective for ethylene dimerization even at room temperature, but Fe₂O₃–ZrO₂ without NiSO₄ did not exhibit any catalytic activity at all. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method. The addition of Fe₂O₃ up to 5 mol% enhanced the acidity, surface area, thermal property, and catalytic activities of catalysts gradually, due to the interaction between Fe₂O₃ and ZrO₂ and due to consequent formation of Fe–O–Zr bond.     

Construction of NiCo2O4 nanoflake arrays on cellulose-derived carbon nanofibers as a freestanding electrode for high-performance supercapacitors

Cellulose has a wide range of applications in many fields due to their naturally degradable and low-cost characteristics, but few studies can achieve cellulose-nanofibers by conventional electrospinning. Herein, we demonstrate that the freestanding cellulose-based carbon nanofibers are successfully obtained by a special design of electrospinning firstly, pre-oxidation and high-temperature carbonization (1600 °C), which display a superior electrical conductivity of 31.2 S·cm^–1 and larger specific surface area of 35.61 m²·g^–1 than that of the polyacrylonitrile-based carbon nanofibers (electrical conductivity of 18.5 S·cm^–1, specific surface area of 12 m²·g^–1). The NiCo₂O₄ nanoflake arrays are grown uniformly on the cellulose-based carbon nanofibers successfully by a facile one-step solvothermal and calcination method. The as-prepared cellulose-based carbon nanofibers/NiCo₂O₄ nanoflake arrays are directly used as electrodes to achieve a high specific capacitance of 1010 F·g^–1 at 1 A·g^–1 and a good cycling stability with 90.84% capacitance retention after 3000 times at 10 A·g^–1. Furthermore, the all-solid-state symmetric supercapacitors assembled from the cellulose-based carbon nanofibers/NiCo₂O₄ deliver a high energy density of 62 W·h·kg^–1 at a power density of 1200 W·kg^–1. Six all-solid-state symmetric supercapacitors in series can also power a ‘DHU’ logo consisted of 36 light emitting diodes, confirming that the cellulose-based carbon nanofiber is a promising carbon matrix material for energy storage devices.     

Development of Fe2O3-CeO2-TiO2/γ-Al2O3 as catalyst for catalytic wet air oxidation of methyl orange azo dye under room condition

In order to develop a catalyst with high activity and stability for catalytic wet air oxidation (CWAO) process at room temperature and atmospheric pressure, we prepared Fe₂O₃-CeO₂-TiO₂/γ-Al₂O₃ by consecutive impregnation, and determined its properties using BET, SEM, XRF, XPS and chemical analysis techniques. The degradation of an azo dye, methyl orange, in CWAO process with Fe₂O₃-CeO₂-TiO₂/γ-Al₂O₃ used as catalyst at room temperature and atmospheric pressure was also investigated, and the results show that the catalyst has an excellent catalytic activity in treating synthetic wastewater containing 500 mg/L methyl orange, and 98.09% of color and 96.08% of total organic carbon (TOC) can be removed in 2.5 h. The degradation pathway of methyl orange was analyzed by UV–vis and FT-IR spectra. The result of leaching tests shows the catalyst has an excellent stability with negligible leaching ions, and the leaching of Ce is effectively controlled by adding Ti, because Ce and Ti in the catalyst take the form of compound oxides, and the deactivation of the catalyst in successive runs is caused by the adsorption of intermediates on the surface and coverage of the active sites. The catalytic activity of the deactivated catalyst can be generally restored by rinsing it in hydrochloric acid followed by calcination.