Black nanostructured BiOCI microspheres were directly synthesized by a hydrothermal method. The black ball- like BiOCI microspheres and black flower-like BiOCI microspheres were obtained using different surfactant. The color of the BiOCI microspheres turned from black to white when being annealed at 400 ℃ in air for 3 h and could be recovered to black by exposure to ultraviolet light for a few hours. The photocatalytic activity of both the black and the white BiOCI microspheres was characterized by the photo-degradation of methyl orange dye under visible light irradiation. The black ball-like nanostructure BiOCI displayed the best photocatalytic activity, compared with the white BiOCI and the black flower-like BiOCI. It can degrade the methyl orange dye to 20% within 70 min under visible light irradiation. The high activity of the BiOCI ball-like sphere may own to its special morphology, strong absorption in visible light range and the existence of oxygen vacancies.
A new solar selective absorbing coating of Mo/NiAlN/NiAlON/SiO_2 multilayer was prepared on stainless steel(SS) substrates by magnetron sputtering for solar thermal power applications. The optical constants and thickness of individual layers were simulated using the Scout software based on the experimentally measured reflectance and transmittance spectra of individual layers. The coating of Mo/NiAlN/NiAlON/SiO_2 with an ideal solar absorptance(α) of 0.945 in the solar spectrum range was designed via the optical constants of each layer in the Scout software. The Mo/NiAlN/NiAlON/SiO_2 coating was deposited via the optimized layer thickness. A good spectral selectivity with absorptance(α=0.936) and emittance(ε=0.09, T=80 ℃) was obtained. This method, which incorporates the optical simulation with the related experiments, provides a convenient approach to obtain the ideal solar selective absorbing coatings.
LIU YingfangWANG CongSUN YingWU YongxinNING YupingWANG WenwenZHANG YongZHAO Shuxi
