Search

Network structured carbonized bacterial cellulose-supported Ru nanoparticles (CBC/Ru), which provide sufficient space for Li2O2 deposition without a significant volume effect and improve the transport of oxygen and electrons, were used as the binder-free oxygen electrode in a Li–O2 battery. The CBC/Ru exhibited high activities and good stability during discharge–recharge processes. [ABSTRACT FROM AUTHOR]

A new restriction effect of hard templates for the shrinkage of mesoporous polymer results in anomalous increase of the mesopore size during carbonization. [ABSTRACT FROM AUTHOR]

Designing and preparing kinetically stable metal–organic frameworks through ligand functionalization can effectively improve their supercapacitive performances. Herein, we have successfully synthesized a novel polythreaded Co-based MOF by choosing a flexible N-donor ligand and a rigid multicarboxylate linker, [Co(HTATB)(dib)]·2H2O (1), where dib is the flexible N-donor 1,4-di(1H-imidazol-1-yl)butane linker and HTATB is the deprotonation mode from 4,4′,4′′-s-triazine-2,4,6-triyl-tribenzoic acid. The bulk Co-MOFs crystals and the corresponding nanorod powders have been evaluated as electrode materials for supercapacitors. The maximum gravimetric capacitance of the nanorod electrode is 2405 F g−1 at 0.75 A g−1 in 4 M KOH, which is higher than 1 M and 6 M KOH solution and seven times larger than that of the bulk-crystal electrode. Furthermore, the nanorod electrode also exhibits excellent Coulombic efficiency (92.2%), rate capability (53.5% after 20 times increase) and good cycling performance (93.5% after 3000 continuous cycles). The excellent electrochemical property may be ascribed to the 3D networks constructed from 2D entangled layered structures facilitating electron transport, sufficient interlayer spaces available for the storage and diffusion of OH− ions, and the small-size effect of the nanorods. Further, the dye adsorption performance of crystalline 1 for methyl orange and Congo red has also been investigated. [ABSTRACT FROM AUTHOR]

Herein, hybrid Cu/Ni-based hexagonal rods were obtained through a competing reaction of dimethylglyoxime with copper acetate and nickel acetate. Using Cu2+ to intervene the coordination equilibrium between Ni2+ and dimethylglyoxime, the length of the rods was altered; moreover, the coordination environments were investigated by adjusting the concentration of Cu2+ and replacing the solvent. The decomposition products porous NiO and CuO/NiO were directly employed as SC electrodes. The CuO/NiO electrode delivered higher specific capacitance and energy with more excellent energy deliverable ability and better cycling stability than the pristine NiO electrode. After 2000 continuous cycles, the capacitance retention of the as-synthesized CuO/NiO electrode was 87.9%. The maximum specific capacitance and energy delivery efficiency of the CuO/NiO electrode were 344 F g−1 and 93.5%, respectively, at a current density of 0.625 A g−1. The better performance of the hybrid sample was mainly due to higher surface area, lower charge-transfer resistance, and possible synergistic effect. Furthermore, MgO/NiO nanoparticles were synthesized and compared to confirm the existence of a synergistic effect. [ABSTRACT FROM AUTHOR]

In this work, we report an ultrasensitive electrochemical biosensor for microRNA-21 (miRNA-21) detection by using a competitive RNA–RNA hybridization configuration. A biotinylated miRNA of the self-same sequence with the target miRNA is mixed with the samples, and allowed competition with the target miRNA for a thiolated RNA probe immobilized onto a tungsten diselenide (WSe2) nanosheet modified electrode. Thereafter the current response is obtained by forming the hybridized biotinylated miRNA with streptavidin–horseradish peroxidase (HRP) conjugates to catalyze the H2O2 + hydroquinone (HQ) system. Benefiting from the high specific surface area of WSe2 nanosheets, the competitive hybridization configuration and the signal amplification of the H2O2 + HQ detection system, the proposed assay exhibits a wide linear range of 0.0001–100 pM towards target miRNA with a detection limit of 0.06 fM (S/N = 3), and shows excellent discrimination ability for base-mismatched miRNA sequences. Therefore, the designed platform has promising prospects for the detection of miRNA in biomedical research and early clinical diagnosis. [ABSTRACT FROM AUTHOR]

Fe2O3 nanocrystals were uniformly anchored onto graphene nanosheets (Fe2O3@GNS) by a nanocasting technique, and the resulting composites were applied as anodes of sodium-ion batteries. Fe2O3@GNS exhibits excellent cycling performance and rate capability. [ABSTRACT FROM AUTHOR]