Search

Functional aerogels composed of regenerated cellulose and tungsten oxide were fabricated by implanting tungsten-oxide nanodots into regenerated cellulose fiber. This superfast photochromic property benefitted from the small size and even distribution of tungsten oxide, which was caused by the confinement effect of the regenerated cellulose fiber. The composite was characterized using XRD and TEM to illustrate the successful loading of tungsten oxide. The composite turned from pale white to bright blue under ambient solar irradiation in five seconds. The evidence of solar absorption and electron paramagnetic resonance (EPR) demonstrated the fast photochromic nature of the composite and its mechanism. Furthermore, carbon fiber filled with preferential growth tungsten-oxide nanorods was obtained by annealing the photochromic composite in a N2 atmosphere. This annealed product exhibited good absorption across the whole solar spectrum and revealed an excellent photothermal conversion performance. The water evaporation rate reached 1.75 kg m−2 h−1 under one sun illumination, which is 4.4 times higher than that of pure water. The photothermal conversion efficiency was 85%, which shows its potential application prospects in seawater desalination. [ABSTRACT FROM AUTHOR]

A new method is applied for preparation of yttria-stablilized zirconia(YSZ) nanocrystals. While crystallization occurs on the surface and interface of SrCO(sub 3) nanoparticles, the agglomeration of YSZ particles is inhibited.

W18O49 with a tunable oxidation state was prepared by addition of NaNO3 or NaBH4 as a redox agent in the solvothermal system. The addition of redox agents has no influence on the crystallization of W18O49. The obtained W18O49 structures keep their morphology as a bundle of nanowires with a regular hexagonal on the cross-section. W18O49 exhibits strong valence-dependent absorption features in the near-IR region. Reduced W18O49 with more W5+ has a higher concentration of oxygen vacancies, which enhances the localized surface plasmon resonance effect. Reduced W18O49 exhibits a high photothermal conversion efficiency of 59.6 % and has good photothermal stability. [ABSTRACT FROM AUTHOR]

Abstract: Fe3+–Nb5+ co-doped SnO2 was prepared at 1200°C by a simple chemical co-precipitation method. The Sn1−2 x Fe x Nb x O2 solid solutions kept cassiterite structure in the range of 0

A flexible, self‐floating W18O49/carbon foam composite is fabricated by calcining melamine foam with W18O49 as an adsorbate in N2 atmosphere. This self‐floating property is simply realized by a carbonization process other than the complicated surface modification process. The simple synthesis procedure helps to increase not only the solar absorption but also the retention of W18O49 in the porous net structure. This composite absorbs almost the whole solar spectrum and generates localized heat at the surface, which is beneficial for water evaporation. Its water evaporation rate is 6.6 times higher than that of pure water. It has a stable cyclic performance over ten cycles under the illumination of simulated sunlight (500 W Xe lamp). Its flexibility makes it easy to reuse and transfer, which is evaluated by the bending deformation test. The W18O49/carbon foam composite is a prospective material in solar energy conversion field, and the preparation procedure is feasible to scale‐up. [ABSTRACT FROM AUTHOR]

Abstract: Mg-doped LaCoO3 particles were prepared in various particle sizes via a modified sol–gel method using excess MgO as pinning particles. The adsorbed oxygen species of the products were studied by XPS, TPD-O2 and TPR-H2. The amount of adsorbed oxygen varied with changes in average particle size and had an important effect on the catalytic activity towards CO oxidation. XPS and TPD-O2 results indicated that there were two kinds of surface oxygen species and that the relative ratio of the surface adsorbed oxygen to lattice oxygen increased with an increasing BET surface area. The catalytic activities of Mg-doped LaCoO3 particles were clearly enhanced with the increase of surface area and the amount of adsorbed oxygen. [Copyright &y& Elsevier]

Abstract: Hydrothermal synthesis, characterization and magnetic properties of a series of ABO3-perovskites LaFe1−x Cr x O3 (0≤x≤1) are reported. The alkalinity in initial reaction mixtures plays a critical role in controlling the designed stoichiometry of the final compositions. Their magnetic properties are strongly dependent on the compositions and a maximum magnetic moment is found for the sample at x=0.5. Weak ferromagnetic interaction observed for the samples from x=0 to 0.9 arises from the presence of Fe–O–Fe antisymmetric exchange and Fe–O–Cr superexchange interaction. The weak ferromagnetism as well as the linear variation of the lattice parameters implies the possible random distribution of Fe and Cr ions in B sites of the perovskites. The evolution of magnetic ordering transition temperatures has a close relationship with substituent ratios, for the competition of antiferromagnetism and ferromagnetism. The saturated magnetic moment shows a great improvement compared with that for the samples synthesized by solid state method. [Copyright &y& Elsevier]

W 18 O 49 with a tunable oxidation state was prepared by addition of NaNO 3 or NaBH 4 as a redox agent in the solvothermal system. The addition of redox agents has no influence on the crystallization of W 18 O 49 . The obtained W 18 O 49 structures keep their morphology as a bundle of nanowires with a regular hexagonal on the cross-section. W 18 O 49 exhibits strong valence-dependent absorption features in the near-IR region. Reduced W 18 O 49 with more W 5+ has a higher concentration of oxygen vacancies, which enhances the localized surface plasmon resonance effect. Reduced W 18 O 49 exhibits a high photothermal conversion efficiency of 59.6 % and has good photothermal stability.