Amorphous NiSe was deposited on the carbon nanotubes (CNTs) networks by the pulsed laser deposition method forming the 2 −1 −1 CC@CNT@NiSe composites. The CC@CNT@NiSe electrode exhibits a high specific capacitance of 696 F g at 2 A g and the specific 2 2 capacitance retention of 74 % in the long life test. To evaluate the practicality of our electrode, we assembled the CC@CNTs@NiSe //CC@CNTs 2 asymmetric supercapacitor using CC@CNTs@NiSe as positive electrode and CC@CNTs as the negative electrode, which shows an energy 2 −1 −1 density of 11.9 Wh kg at a power density of 242 W kg . This work highlights the advantageous electrochemical performance of NiSe film on 2 CNTs, in which the highly conductive CNTs provide plentful electronic conduction channels and the NiSe film exposures more active sites.

Weak polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) were assembled into {PAH/PAA} n layer-by-layer films on electrodes. The cyclic voltammetry (CV) response of ferrocenecarboxylic acid (Fc(COOH)) at {PAH/PAA} 5 film electrodes assembled under the specific condition showed pH-sensitive "on-off" switching property. This property was further used to control the electrocatalytic oxidation of glucose by glucose oxidase (GOD) with Fc(COOH) as the electron transfer mediator, so that the pH-switchable bioelectrocatalysis could be realized. The mechanism of pH-sensitive behavior of the system was explored and believed to originate from the pH-dependent structure change of the films.

No abstract

Series of Ca1−x Pr x Co2As2 (x = 0, 0.10, 0.25, 0.4, 0.6, 0.75, 0.85, 1) single crystals have been synthesized in order to clarify the variation of magnetic order from antiferromagnetic (AFM) in CaCo2As2 to ferromagnetic (FM) in PrCo2As2. It is found that the lattice constant of c-axis are contracted with the introduction of Pr into Ca sites in CaCo2As2. Electronic transport measurements reveal the metallicity in this system. Systematic magnetic measurements and analysis show that substituting only 10% of Pr for Ca changes the magnetic ground state from A-type AFM ordering of Co magnetic moment in CaCo2As2 to FM ordering in Ca1−x Pr x Co2As2 (0.1 ⩽ x ⩽ 1). Most importantly, the abrupt drop of low temperature magnetic susceptibility below T FiM with x ⩾ 0.25 and the observed magnetic pole reversal with x ⩾ 0.4 suggests an AFM coupling between Co 3d and Pr 4f magnetic sublattice. Finally, a detailed magnetic phase diagram in this system has been obtained.

No abstract