Shuang Liang,Guozhe Sui,Dongxuan Guo,Ze Luo,Rongping Xu,Hong Yao,Jinlong Li,Chao Wang
The development of efficient heterojunctions with enhanced photocatalytic properties is considered a promising approach for photocatalytic hydrogen production. In this study, graphitic carbon nitride (g-C 3 N 4 )-wrapped nickel-doped zinc oxide/carbon (Ni-ZnO@C/g-C 3 N 4 ) core-double shell heterojunctions with unique core-double shell structures were employed as efficient photocatalysts through an innovative approach. Ni doping can enhance the intensity and range of visible light absorption in ZnO, and the carbon core coupled with the hollow double-shell structure can accelerate the charge transfer rate and improve the photon utilization efficiency. Meanwhile, the construction of the Z-scheme heterojunction extended the electron-hole pair transport path. In addition, the Z-scheme charge-transfer mechanism of Ni-ZnO@C/g-C 3 N 4 under simulated sunlight was verified by photoluminescence (PL) and electron spin resonance (ESR) experiments. As a result, the obtained photocatalyst acquired a high hydrogen evolution rate of 336.08 μmol g −1 h −1 , which is 36.49 times higher than that of pristine ZnO. Overall, this work may provide a pathway for the construction of highly efficient photocatalysts with unique core-double shell structures.
High dielectric constant polymer dielectrics have attracted a great deal of attention in flexible electronics. However, it appears to be a paradox for polymer dielectrics that the enhancement of their dielectric constant often comes along with the increase of dielectric loss. Hence, we reported core@double shell structured filler/poly(vinylidene fluoride) (PVDF) composites to overcome this paradox. The hybrid filler with BaTiO 3 (BT) as the core, conductive carbon as the inner shell, and insulating polydopamine (PDA) as the outer shell was synthesized. As a result, the BT@C@PDA/PVDF composites at the filler content of 11 vol% exhibit an outstanding dielectric performance with a dielectric constant of 45 and a dielectric loss of 0.053 at 10 3 Hz. This phenomenon can be attributed to the increased interfacial polarization induced by the inner carbon shell and the conductive paths blockade caused by the outside PDA shell inside the BT@C@PDA/PVDF composites. This work reveals that rational design of core@double shell structured hybrid fillers maybe a promising way to optimize the overall dielectric performance of the PVDF-based composites.
In this paper, we designed a core@double-shell nanostructure to enhance the electromagnetic wave absorption performance of hybrid nanospheres. Herein, the core@double-shell structured Fe 3 O 4 @polyaniline@MnO 2 nanospheres were successfully prepared by a facile solvothermal process and in situ polymerization methods. The morphology, structure, magnetism and microwave absorption properties were studied. The results reveal that the FPM nanospheres exhibit extraordinary microwave absorbing performance compared to those of either Fe 3 O 4 or Fe 3 O 4 @polyaniline nanospheres. The minimum reflection loss of the FPM nanospheres is − 14.7 dB at 15.76 GHz with the thickness of 3.5 mm, and the corresponding effective absorption bandwidth can reach 4.75 GHz. The perfect EMW absorption of nanospheres can be ascribed to multi-interface polarization, multiple reflections and good impedance matching originated from the core@double-shell nanostructure.
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