Polyaniline encapsulated Ti-MOF/CoS for efficient photocatalytic hydrogen evolution

We report the study of conductive polyaniline (PANI) chain embedded Ti-MOF functionalized with CoS as a cocatalyst for hydrogen evolution reaction (HER) application. The post synthetically modified hybrid photocatalyst PANI/Ti-MOF/CoS greatly influences the redox and e^? ? h⁺ separation process and exhibits an impressive rate of HER (～1322 μmol h^?1g^?1), suppressing the pristine Ti-MOF (～62 μmol h^?1g^?1) with apparent quantum yield (AQY) of ～3.2 and transient current response of ～46.4 μA cm^?2. In this system, Ti-MOF provides the circulation of Ti³⁺ and Ti⁴⁺ to the reaction of photocatalytic H₂ generation, where the additional PANI and CoS amended the performance of H₂ production through electron enrichment and thereby improving the stability and integrity of Ti-MOF. The Electrochemical studies demonstrated increased photocurrent by interweaving Ti-MOF crystal with PANI through cation-π interaction thereby enhancing interface connection and then promoting electron transfers. The charge dynamics revealed the initial charge transfer from photoexcited PANI to encapsulated MOF framework to boost the photocatalytic performance of the system. Further, the electron movement at the Ti-MOF/CoS interface is investigated through work function and electrochemical potential of electrons (Fermi level). DFT results demonstrate the importance of CoS in improving the photocatalytic performance of hybrid Ti-MOF catalyst, which leads to superior catalytic behaviour. These results establish that the encapsulation of catalytic active sites inside MOFs with desirable energy band gaps would be an ideal choice for the production of solar fuels.     

FeOOH–CoS composite catalyst with high catalytic performances for oxygen evolution reaction at high current density

Water electrolysis is an efficient approach for high-purity hydrogen production. However, the anodic sluggish oxygen evolution reaction (OER) always needs high overpotential and thus brings about superfluous electricity cost of water electrolysis. Therefore, exploiting highly efficient OER electrocatalysts with small overpotential especially at high current density will undoubtedly boost the development of industrial water electrolysis. Herein, we used a simple hydrothermal method to prepare a novel FeOOH–CoS nanocomposite on nickel foam (NF). The as-prepared FeOOH–CoS/NF catalyst displays an excellent OER performance with extremely low overpotentials of 306 and 329 mV at 500 and 1000 mA cm⁻² in 1.0 M KOH, respectively. In addition, the FeOOH–CoS/NF catalyst can maintain excellent catalytic stability for more than 50 h, and the OER catalytic activity shows almost no attenuation no matter after 1000 repeated CV cycles or 50 h of stability test. The high catalytic activity and stability have exceeded most non-noble metal electrocatalysts reported in literature, which makes the FeOOH–CoS/NF composite catalyst have promising applications in the industrial water electrolysis.     

CoS薄膜的制备和介电性质的研究

以CoCl2和Na2S为试剂,采用改进的化学浴沉积法在玻璃衬底上制备出了CoS薄膜,并分别以偏光显微镜和LCR仪对样品的形貌和介电性质进行了研究。     

石墨烯负载纳米二硫化钴的制备及其在锂离子电池方面的应用研究

采用二次水热法将纳米二硫化钴负载于石墨烯上,并通过结构表征和电化学性能测试,探讨了纳米二硫化钴/石墨烯材料作为锂离子电池负极的性能。电容量测试结果表明：在电流密度为100 mA/g条件下,二硫化钴/石墨烯复合材料的首周充放电容量分别为1 610 mA·h/g和774 mA·h/g,测算出的库伦效率为48.1%;循环性能测试结果表明：经过50次循环测算后的复合材料的放电比容量为302 mA·h/g,容量保持率为33.4%;倍率性能测试结果表明：当电流密度回复到100 mA/g时,复合材料的比容量恢复至550 mA·h/g。实验制备的纳米二硫化钴/石墨烯复合材料在锂电池负极的应用上表现出了优异的循环性能和倍率性能。     

新型锂离子蓄电池阳极材料CoS2

报道了一种新型锂离子蓄电池阳极材料CoS2,利用X射线衍射(XRD)、电子扫描电镜(SEM)和BET等技术研究了其结构和形貌。XRD显示CoS2为立方结构,晶胞参数a=0.5531nm,SEM观察其颗粒大约在30mm,表面有丰富的微结构。对不同乙炔黑含量的材料进行研究发现,乙炔黑含量为30%的样品具有较好的电化学性能,首次最大嵌锂容量高达1280mAh·g-1。非原位XRD研究了材料在充放电过程中结构的变化,同时研究了其反应机理。     

Vertically grown CoS nanosheets on carbon cloth as efficient hydrogen evolution electrocatalysts

The development of efficient and inexpensive water splitting electrocatalysts is essential for the large-scale production of hydrogen. Herein, we show that a novel nanohybrid with CoS nanosheets vertically grown on carbon cloth (CoS/CC) can be used as an efficient self-supported hydrogen-evolving cathode for water splitting over a wide pH range. This material affords a current density of 10 mA/cm² at a small overpotential of 192 mV and 212 mV in basic and acidic media, respectively, along with a long-term stability for over 50 h. The unique 3D structure constructed by the vertically arranged nanosheets and the intimate contact between the CoS nanosheets and the underlying conductive carbon are believed to be responsible for the excellent catalytic performance.     

QoS技术在IP网络中的部署策略简介

本文以某运营商的IP网络为例详细介绍了QoS设计方案.     

CoS高效脱硫剂在生产中的应用

根据脱硫工段干法脱硫不能满足城市煤气的指标要求,对系统进行了改造.选用湿法脱硫装置,使用CoS高效脱硫剂降低煤气中硫化氢的含量,可提高经济效益和社会效益.     

Cyclic Polling-Based Dynamic Bandwidth Allocation for Differentiated Classes of Service in Ethernet Passive Optical Networks

Ethernet passive optical networks (EPONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and customer sites. Dynamic bandwidth allocation (DBA) provides statistical multiplexing between the optical network units for efficient upstream channel utilization. To support dynamic bandwidth distribution, a cyclic polling-based DBA algorithm for differentiated classes of service in EPONs is proposed. It is shown that an interleaved polling scheme severely decreases downstream channel capacity for user traffic when the upstream network load is low. To obtain realistic simulation results, synthetic traffic that exhibits the properties of self-similarity and long-range dependence is used. Network performance under various loads is analyzed. Specifically, frame delays for different classes of traffic are considered.     

量子点敏化太阳电池FTO/CoS/CuS对电极的制备与性能

摘要：本文采用恒电位电沉积方法在FTO导电玻璃表面依次沉积CoS和CuS,形成 FTO/CoS/CuS复合对电极用于量子点敏化太阳电池。确定了电沉积电位和电沉积时间,并研究了电沉积温度对电极形貌及电催化活性的影响。对电极的表面形貌和微观结构采用SEM和TEM方法进行表征;对电极的光反射性能采用紫外可见分光光度计进行测试;对电极的电化学性能通过测试交流阻抗、Tafel极化曲线以及J-V曲线进行表征。研究结果表明,FTO/CoS/CuS对电极与电解液界面处的电荷转移阻抗较低,具有更高的光反射率及电催化活性。与Au片、FTO/CoS和FTO/CuS对电极相比,光电转化效率分别提高了132.9%,46.6%,26.9%。