Liuyang Zhang

Core–Shell Nitrogen‐Doped Carbon Hollow Spheres/Co3O4 Nanosheets as Advanced Electrode for High‐Performance Supercapacitor

Co3 O4 /nitrogen-doped carbon hollow spheres (Co3 O4 /NHCSs) with hierarchical structures are synthesized by virtue of a hydrothermal method and subsequent calcination treatment. NHCSs, as a hard template, can aid the generation of Co3 O4 nanosheets on its surface; while SiO2 spheres, as a sacrificed-template, can be dissolved in the process. The prepared Co3 O4 /NHCS composites are investigated as the electrode active material. This composite exhibits an enhanced performance than Co3 O4 itself. A higher specific capacitance of 581 F g-1 at 1 A g-1 and a higher rate performance of 91.6% retention at 20 A g-1 are achieved, better than Co3 O4 nanorods (318 F g-1 at 1 A g-1 and 67.1% retention at 20 A g-1 ). In addition, the composite is employed as a positive electrode to fabricate an asymmetric supercapacitor. The device can deliver a high energy density of 34.5 Wh kg-1 at the power density of 753 W kg-1 and display a desirable cycling stability. All of these attractive results make the unique hierarchical Co3 O4 /NHCS core-shell structure a promising electrode material for high-performance supercapacitors.

TiO2–MnOx–Pt Hybrid Multiheterojunction Film Photocatalyst with Enhanced Photocatalytic CO2-Reduction Activity

Photocatalytic CO2 conversion into solar fuels has an alluring prospect. However, the rapid recombination of photogenerated electron-hole pairs for TiO2-based photocatalyst hinders its wide application. To alleviate this bottleneck, a ternary hybrid TiO2-MnO x-Pt composite is excogitated. Taking advantage of the surface junction between {001} and {101} facets, MnO x nanosheets and Pt nanoparticles are selectively deposited on each facet by a facile photodeposition method. This design accomplishes the formation of two heterojunctions: p-n junction between MnO x and TiO2 {001} facet and metal-semiconductor junction between Pt and TiO2 {101} facet. Both of them, together with the surface heterojunction between {001} and {101} facets, are contributive to the spatial separation of the photogenerated electron-hole pairs. Thanks to their cooperative and synergistic effect, the as-prepared composite photocatalyst exhibits a promoted yield of CH4 and CH3OH, which is over threefold of pristine TiO2 nanosheets films. The conjecture of the mechanism that selective formation of multijunction structure maximizes the separation and transfer efficiency of photogenerated charge carriers is proved by the photoelectrochemical analysis. This work not only successfully achieves an efficient multijunction photocatalyst by ingenious design but also provides insight into the mechanism of the performance enhancement.

Fabrication of Al-Cu System with Functionally Graded Density Profiles*

To lower the temperature-enhancement inside the target material and achieve higher pressure and velocity is important in dynamic high-pressure technology. It can be realized through quasi-isentropic loading by density functionally graded materials (DFGM). A kind of Al-Cu DFGM was hot-pressed by powder stacking with adjusting soaked temperature, load interval and pressure et al. The FGM has quasi-continuous density variation along the thickness direction.