A Reversible Redox Strategy for SWCNT‐Based Supercapacitors Using a High‐Performance Electrolyte

In order to achieve pesudocapacitive performance of single‐wall carbon nanotube (SWCNT) electrodes, a high‐efficient and reversible redox strategy utilizing a redox‐mediated electrolyte for SWCNT‐based supercapacitors is reported. In this novel redox‐mediated electrolyte, the single‐electrode specific capacitance of the supercapacitor is heightened four times, reaching C=162.66 F g^?1 at 1 A g^?1. The quick charge‐discharge ability of the supercapacitor is also enhanced, and the relaxation time is as low as 0.58 s. Furthermore, the supercapacitor shows an excellent cycling performance of 96.51 % retention after 4000 cycles. The remarkable results presented here illustrate that the redox strategy is a facile and straightforward approach to improve the performances of SWCNT electrodes.     

Visible light-driven flower-like Bi/BiOClxBr(1−x) heterojunction with excellent photocatalytic performance

In this work, a series of flower-like Bi/BiOCl_xBr_(1−x) heterojunction photocatalysts have been developed. Bi nanoparticles were grown on the BiOCl_xBr_(1−x) nanosheets via an in situ chemical reduction with the assistance of cetyltrimethylammonium chloride and cetyltrimethylammonium bromide aqueous solution. The in situ growth of Bi nanoparticles on the BiOCl_xBr_(1−x) nanosheets could not only give rise to the optical absorption in the visible region, but also promote the photocatalytic performance of BiOCl_xBr_(1−x). Bi/BiOCl_0.8Br_0.2 exhibited the highest photocatalytic performance, which could completely degrade RhB in 12 min under the UV light irradiation and 6 min under visible light irradiation, respectively. Moreover, holes and superoxide radicals were verified to be the primarily active species in the photocatalytic process.

     

Synthesis,structure and characterization of a new trinuclear magnetic semiconductor PbI4[Cu(Me2dtc)(bipy)]2

A new trinuclear magnetic lead iodide semiconductor PbI₄[Cu(Me₂dtc)(bipy)]₂ (Me₂dtc = N,N-dimethyldithiocarbamate, bipy = 2,2′-bipyridine) has been synthesized, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P2₁/c with a = 22.2137(11) Å, b = 11.3687(4) Å, c = 15.3382(8) Å, β = 102.372(3)°, Z = 4, V = 3783.6(3) Å³. It is built up by [PbI₄S₂] octahedron linked with two [CuIS₂N₂] square pyramids through common edges. The adjacent molecules stack with each other to form a two-dimensional (2D) layer along ab plane via the π–π stacking interactions between aromatic groups of bipy ligands. Then the 2D layers are further extended into a three-dimensional structure through hydrogen bonding interactions. The temperature dependence of the electrical conductivity indicates that this compound exhibits semiconducting character. The title brown–black compound has an optical bandgap of 1.26 eV, and the variable-temperature magnetic susceptibility measurement indicates weak antiferromagnetic behavior with J = ?1.06 cm^?1.     

Valence and structural transitions in the mixed Ru-Ir perovskites Ba2PrRu1−xIrxO6

The valence state of Pr in the B-site ordered double perovskites Ba₂PrRu_1−xIr_xO₆ is shown to be sensitive to both the precise Ru:Ir content and temperature. Pr L_III XANES measurements show that at room temperature the Pr is trivalent in the Ru-rich compounds with x<0.25. At higher Ir contents the Pr is tetravalent. High-resolution powder synchrotron X-ray and neutron diffraction methods have been used to study the composition and temperature dependence of the crystal structures of these oxides. The Ru and Ir are statistically distributed on one of the two available B-sites. The oxides undergo an apparently first-order monoclinic P2₁/n to tetragonal P4/mnc phase transition in response to the change on the Pr and Ru/Ir valence. High temperatures and Ru contents favor the lower symmetry monoclinic structure, that is arises from the presence of the larger Pr^III cations. The variations in the observed metal-oxygen bond distances are consistent with a simultaneous change in the valence of the Ru/Ir accompanying the Pr^III-Pr^IV valence transition.