MnO/Nitrogen-doped graphene composite cathode for high performance lithium oxygen batteries

本文采用水热法制备了MnO/氮掺杂石墨烯复合材料. 作为非水锂空气电池的正极催化剂, 该复合材料表现出了优异的电化学性能以及循环稳定性.; 在充放电电流密度为0.05 mA cm~(-2)时, 其能量效率高达84.6%, 远高于目前文献所报道的非贵金属催化剂的能量效率,; 也超过了基于贵金属的催化剂. 其氧还原反应(ORR)和氧析出反应(OER)的过电势分别仅为0.11和0.41 V.; 扫描电子显微镜(SEM)和透射电子显微镜(TEM)结果表明, 所制备的MnO纳米颗粒能够均匀地分散在氮掺杂石墨烯的表面.; 密度泛函理论(DFT)计算揭示, MnO(100)面是主要的催化活性面, 其理论ORR和OER的过电势分别仅为0.21与0.24 V,; 充放电电势差为0.45 V, 与实验结果0.52 V相当.MnO/nitrogen-doped graphene (MnO/NG) composite cathode was fabricated by; a facile one-pot method as cathode catalyst for non-aqueous lithium; oxygen batteries. It exhibited superior electrochemical performance with; higher round-trip efficiency and better cyclic stability. It showed a; high round-trip efficiency of 84.6% at the current density of 0.05 mA; cm~(-2) with the discharge and charge overpotentials of 0.11 and 0.41 V,; respectively. Through scanning electron microscopy, transmission; electron microscopy and X-ray photoelectron spectroscopy, it was; confirmed that MnO nanoparticles were homogeneously dispersed on NG; surface. The density functional theory calculations demonstrated that; the superior electrochemical performance of MnO/NG might be attribute to; the exposure of stoichiometric MnO (100) surface, with the ORR and OER; overpotential only to be 0.21 and 0.24 V, respectively. The; discharging-charging voltage gap is 0.45 V, in good agreement with the; experimental value of 0.52 V.国家重点基础研究发展计划; 国家自然科学基金; 国家基础科学人才培养基

Inhibitory Effect of Salt Marsh Halophyte Salicornia Europaea on Prorocentrum Donghaiense

利用植物抑制藻类生长是目前海洋赤潮治理的有效生态手段之一。以东海原甲藻为材料,研究了滩涂盐生植物盐角草对东海原甲藻生长的抑制效应。结果显示:盐角草过滤培养液和4种根的有机相提取物(甲醇相、正丁醇相、氯仿相和石油醚相)能显著抑制东海原甲藻的生长,改变细胞大小。其中,石油醚相和正丁醇相提取物还能影响藻细胞CHl A含量。有机相提取物中以甲醇相提取物的抑制效果最强,对盐角草甲醇相提取物进行gC-MS分析,得到27种化合物,含量最高的3个组分为5-羟甲基-2-呋喃甲醛、棕榈酸和4-乙烯基-2-甲氧基-苯酚。研究表明:滩涂盐生植物盐角草能够抑制东海原甲藻的生长,具备开发新型赤潮生物抑藻剂的潜力,有望应用于海洋赤潮的防治。Phytoremediation, as one of the mechanisms for controlling marine algal blooms, is becoming an ecologically sustainable approach in recent years.In this work, we investigated the inhibitory effect of salt marsh halophyte Salicornia europaea on Prorocentrum donghaiense.Growth of P.donghaiense was not inhibited by the water extracts of S.europaea root, but the culture filtrate of S.europaea and four organic extracts.The inhibitory of organic extracts was dosedependent, and P.donghaiense was most sensitive to the methanol extract.GC-MS analysis of the methanol extract revealed 27 lipophilic compounds, in which 2-furancarboxaldehyde, 5-(hydroxymethyl)-, n-hexadecanoic acid and 2-methoxy-4-vinylphenol were the most abundant components.Together, our results suggested that salt marsh halophyte S.europaea might be applied as a new type material to control the growth of P.donghaiense.国家“863”计划项目(2007AA091704); 浙江省重点科技创新团队项目(2010R50039); 杭州市科技计划项目(20120433B19&20130533B11