Hollow waxberry-like rutile- and anatase-TiO 2 /SnO 2 (TiO 2 @SnO 2 ) hierarchical architecture was fabricated for efficient photocatalysis . A Topotactic synthetic method, including the synthesis of CaTiO 3 /CaSnO 3 precursors and subsequent transformation into TiO 2 @SnO 2 , was used. Rutile TiO 2 nanorods nearly radial alignment grow on the external surface of the hollow sphere composed of anatase TiO 2 and SnO 2 nanoparticles . Because the hollow hierarchical structure enhances light harvesting ability and the tightly connected interface among different components improves the electron transfer efficiently, a waxberry-like TiO 2 @SnO 2 -5% sample with appropriate phase composition exhibits excellent photocatalytic performance. The sample behaved superior cycle stability.
Polyaniline (PANI) nanorod arrays were facilely grown on the surface of carbon microspheres via a simple dilute polymerization. The as-synthesized carbon@polyaniline nanorod arrays microspheres (C@PANI) show specific waxberry-like shape, and exhibit superior microwave absorption capacities compared with pure PANI and carbon microsphere. The minimum reflection loss ( RL ) value of C@PANI microspheres reaches −59.6 dB at 15.5 GHz with a thin thickness of 2.2 mm and the effective bandwidth (reflection loss values of less than −10 dB) is as wide as 5.4 GHz (from 12.6 to 18 GHz). The in-depth analyses of the geometrical shape and composition relationship demonstrate that the enhanced microwave absorption properties of C@PANI microspheres was mainly correlate with the unique PANI nanorod arrays and synergistic effect.
Jinming Li,Xiang Li,Jindong Hu,Chaochao Guo,Guoxin Liu,Yang Liu,Siqi Huan,Zhiguo Li
The practical adoption of aqueous energy storage devices hinges on advancing high energy density, long cycle life, and environmental tolerance, which concentrates on the rapid transport of multivalent electrolyte ions within electrodes. Aiming to address the limitations of traditional carbon electrodes, we proposed the morphological modulation of bio-derived superstructured carbon. Waxberry-like superstructured carbon (WSCC) with interconnected surface open-pore and internal gradient channels was constructed by regulating the hydrophilicity of the hydrophobic part in the carbon precursor molecules. After loading MnO 2 and Zn on WSCC, waxberry-like cathode and anode for aqueous zinc-ion batteries (AZIBs) were produced, both featuring the waxberry-like morphology and highly effective porosity matching Zn 2+ . Benefiting from the morphology effect of WSCC, the transport of Zn 2+ was switched from inter-particle-type to interfacial-type within the electrodes, enhancing transport rate and accessibility. The assembled AZIBs exhibited a high energy density of 367.13 Wh kg −1 . Meanwhile, the waxberry-like morphology minimized the nucleation barrier and altered zinc dendrite growth direction to delay the deterioration of AZIBs. Therefore, excellent cycling stability with capacity retention of 97 % was displayed up to 4,000 cycles, a significant improvement of 60 % over the cycle numbers of bare Zn. Moreover, the AZIBs showed superior low-temperature performance and reliable operability due to the unique morphological effect of WSCC, exhibiting a specific capacity of 164.67 mAh g −1 at −20 °C and stable cyclability between −20 and 20 °C over three cycles. The bio-based high-performance AZIBs combine cycling stability and low-temperature tolerance while meeting the demands of scalability and sustainability.
Dawei Liu,Yunchen Du,Ping Xu,Fengyuan Wang,Yahui Wang,Liru Cui,Honghong Zhao,Xijiang Han
Hierarchical microstructures are playing important roles in the design and fabrication of high-performance microwave absorbing materials (MAMs) owing to their unique advantages. In this work, a series of special “double-hierarchical” N-doped carbon nanotubes wrapping waxberry-like Ni@C microspheres (NC@NCNTs) have been rationally designed and successfully fabricated by two-step pyrolysis processes, where the loading amount of NCNTs on the waxberry-like Ni@C microspheres can be easily modulated by changing the dosage of melamine. Benefiting from sufficient attenuation ability and good impedance matching, NC@NCNTs-2, whose relative carbon content is 51.1 wt%, exhibits the best reflection loss (RL) characteristics among this series of composites, including the minimum RL intensity of −41.5 dB and an effective absorption bandwidth of 5.2 GHz with an absorber thickness of only 1.7 mm. This performance is superior to that of many homologous Ni/C composites reported previously. The investigation on EM properties indicates that the unique “double-hierarchical” architecture of NC@NCNTs can not only create stronger dipole orientation and interfacial polarization relaxation, but can also result in higher conductive loss as well as extra multiple reflection effects for incident electromagnetic waves. We believe that these results will provide some inspirations and pathways for the production of high-performance MAMs with senior microstructures in the future.
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