Hierarchical semiconductors are the most important photocatalysts, especially for visible light-induced hydrogen production from water splitting. We demonstrate herein a hierarchical electrostatic assembly approach to...
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Hierarchical semiconductors are the most important photocatalysts, especially for visible light-induced hydrogen production from water splitting. We demonstrate herein a hierarchical electrostatic assembly approach to hierarchical CdS/m-TiO 2 /G ternary photocatalyst, which exhibits high photoactivity and excellent photostability (more than twice the activity of pure CdS while 82% of initial photoactivity remained after 15 recycles during 80 h irradiation). The ternary nanojunction effect of the photocatalyst has been investigated from orbitals hybrid, bonding energy to atom-stress distortion and nano-interface fusion. And a coherent separation mechanism of charge carriers in the ternary system has been proposed at an atomic/nanoscale. This work offers a promising way to inhibit the photocorrosion of CdS and, more importantly, provide new insights for the design of ternary nanostructured photocatalysts with an ideal heterojunction.
The coupling between antiferrodistortion (AFD) and ferroelectric (FE) polarization, universal for all tilted perovskite multiferroics, is known to strongly correlate with domain wall functionalities in the materials. ...
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The coupling between antiferrodistortion (AFD) and ferroelectric (FE) polarization, universal for all tilted perovskite multiferroics, is known to strongly correlate with domain wall functionalities in the materials. The intrinsic mechanisms of domain wall phenomena, especially AFD-FE coupling-induced phenomena at the domain walls, have continued to intrigue the scientific and technological communities because of the need to develop future nanoscale electronic devices. Over the past years, theoretical studies have often shown controversial results, owing to the fact that they are neither sufficiently nor directly corroborated with experimental evidence. In this work, the AFD-FE coupling at uncharged 180° and 71° domain walls in BiFeO3 films is investigated by means of aberration-corrected scanning transmission electron microscopy with high-resolution scanning transmission electron microscopy and rationalized by phenomenological Landau-Ginzburg-Devonshire (LGD) theory. We reveal a peculiar morphology at the AFD-FE walls, including kinks, meandering, and trianglelike regions with opposite oxygen displacements and curvature near the interface. The LGD theory confirms that the tilt gradient energy induces these unusual morphologies and the features would change delicately with different kinds of domain walls. Moreover, the 180° AFD-FE walls are proved to be conductive with an unexpected reduction of the Fe-O-Fe bond angle, which is distinct from theoretical predictions. By exploring AFD-FE coupling at the domain walls, and its induced functionalities, we provide exciting evidence into the links between structural distortions and its electronic properties, which provide great benefit for fundamental understanding of domain wall functionalities as well as functional manipulations for novel nanodevices.
Laminated ZrB2-SiC ceramics with porous ZrB2 interlayers were successfully prepared by Spark plasma Sintering (SPS)/tape casting, laminating and Reactive Spark Plasma Sintering (RSPS). ZrB2-SiC plates were sintered by...
Laminated ZrB2-SiC ceramics with porous ZrB2 interlayers were successfully prepared by Spark plasma Sintering (SPS)/tape casting, laminating and Reactive Spark Plasma Sintering (RSPS). ZrB2-SiC plates were sintered by SPS. And ZrO2-B4C sheets were prepared by tape casting, which will undergo reducing reaction that produces porous ZrB2 interlayers during SSPS processing. The ZrB2-SiC plates and ZrO2-B4C sheets were laminated alternately and reactive sintered to laminated ceramics with porous ZrB2 interlayers. The porosity and thickness of the porous layers were controlled by the tape casting processing and sintering pressure. The microstructure of the laminated ZrB2-SiC ceramics was analysed and discussed in details.
The ZrB2/SiC/Zr2Al4C5 multi-phase ceramics were fabricated by spark plasma sintering (SPS) at 1800 °C for 3 min under 20 MPa in an vacuum. Oxidation behavior of multi-phase ceramics were investigated using thermo...
The ZrB2/SiC/Zr2Al4C5 multi-phase ceramics were fabricated by spark plasma sintering (SPS) at 1800 °C for 3 min under 20 MPa in an vacuum. Oxidation behavior of multi-phase ceramics were investigated using thermo gravimetric analysis (TGA) from 20 °C to 1500 °C and muffle furnace in stagnant air at 1200 °C. Samples were analyzed after oxidation by X-ray diffraction (XRD), scanning electron microscopy (SEM) along with energy dispersive spectroscopy (EDS) to determine the reaction products and to observe the microstructure. The results showed that the aluminium borate and mullite crystallize on the surface in the samples oxidized. The effect of Zr2Al4C5 content on the oxidation resistance of the ZrB2 ceramics were discussed respectively, and oxidation mechanism was also analysised.
Microcellular foams have a widely applications in many industries due to their superior properties. In this paper, the polymethymethacrylate (PMMA)/graphene oxide (GO) microcellular foams were prepared by supercritica...
Microcellular foams have a widely applications in many industries due to their superior properties. In this paper, the polymethymethacrylate (PMMA)/graphene oxide (GO) microcellular foams were prepared by supercritical carbon dioxide as a friendly foaming agent. The effect of graphene oxide amount on cellular structure and mechanical strength of foams had been investigated. Microstructure characterization bases on scanning electron microscopy (SEM). The cell size and cell density were calculated via image analysis. It was found that the average foam cell size was decreased from 20.1 μm to 2.2 μm and the cell density was increased from 2.8×108 to 3.3×1010 when 1.5wt.% GO sheets were added into PMMA matrix. In addition, the compression strength of polymeric foams was increased from 13 MPa to 39 MPa.
One-dimensional (1D) van der Waals (vdW) materials have garnered significant attention for their unique structures and properties, making them promising candidates for various applications in optoelectronics, catalysi...
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