WO 3 nanostructures with various morphologies and crystallinity (such as cylinder-like WO 3 nanorod arrays (WNRs-1), porous WO 3 nanofibers, WO 3 nanoflake arrays, sharp cone-like nanorod arrays (WNRs-2) and annealed cylinder-like WNRs-1) were prepared on FTO substrates by using a hydrothermal method without organic additives. The effects of morphology, size and crystallinity on the electrochromic properties of WO 3 nanostructures were systematically investigated by scanning electron microscopy, X-ray diffraction, cyclic voltammetry and chronoamperometry. The WNRs-1 exhibited excellent cyclic stability, wide optical modulation (64%), and relatively high coloration efficiency (61 cm 2 C -1 ). A fast switching speed of 5 s and 6 s for bleaching and coloration are achieved for the WNRs-1 after annealing. Moreover, the relationship between the micro-morphologies/structures and electrochromic performance of WO 3 nanostructures was also discussed. the deintercalation) compared with the unannealed WNRs-1, which may be closely related to the different crystalline forms. The h-WO 3 could accommodate abundant Li-ions due to its three possible locations (trigonal cavity, hexagonal window and four-coordinated square window).However, when the h-WO 3 is translated to m-W 18 O 49 , a large amount of hexagonal windows disappear which result in low capacity for Li-ions. Moreover, the cyclic reversible value is only 71% calculated from the charge/discharge densities, which is mainly ascribed to the oxygen deficiency.Greater oxygen deficiency in W 18 O 49 could capture a certain amount of electrons in the deintercalation. Furthermore, this experiment has settled the disputes of electrochromic mechanism between the double injection model 33 and the small polaron model 34 . A major focus of the debate is the valence transformation of tungsten element in the color-changed process. The double injection model suggested that the valence transformation of tungsten element changed between plus five and plus six. While the small polaron model believed that it should be between plus five and plus four.From Fig. 8, we know that there indeed is a mixture of two kinds of valence changes in the annealed WNRs-1 during the charging and discharging process.
Ti-bearing electric arc furnace slag (Ti-bearing EAF slag) is the main solid waste generated in the direct reduction iron making process. During the extraction process of Ti from Ti-bearing EAF slag, a byproduct containing abundant Si and Al was seldom utilized, thus leading to waste of valuable elements and secondary pollution. In this paper, NaA zeolite (6Na 2 O$6Al 2 O 3 $12SiO 2 ) and sodalite (SOD, 4Na 2 O$3Al 2 O 3 $6SiO 2 ) were synthesized successfully using the by-product as a precursor. The effects of the SiO 2 /Al 2 O 3 molar ratio (n(SiO 2 )/n(Al 2 O 3 )), H 2 O/Na 2 O molar ratio (n(H 2 O)/n(Na 2 O)), hydrothermal temperature and time on the crystal phase and microstructure of the prepared zeolites were systematically investigated. The results indicated that NaA zeolite with good crystallinity and cubic morphology was obtained at 140 C for 3 h with n(SiO 2 )/n(Al 2 O 3 ) and n(H 2 O)/n(Na 2 O) fixed at 2.0 : 1 and 100 : 1, respectively. Decreasing n(H 2 O)/n(Na 2 O), raising the hydrothermal temperature and prolonging the hydrothermal time were beneficial for the formation of spherical SOD zeolite. The phase transformation between NaA and SOD zeolite was discussed and a mechanism was proposed to explain the phenomenon of these zeolites coexisting in the obtained samples. In addition, the removal performances of Cu 2+ in aqueous solutions using zeolites synthesized at different temperatures were studied. The maximum removal capacity of the prepared zeolite can reach 1.346 mmol g À1 for 180 min.
Well-oriented and crystalline WO3 nanorod arrays (WNRAs) decorated with Mo were synthesized on fluorine doped tin oxide (FTO) substrate by the hydrothermal method. The effects of Mo doping, hydrothermal reaction time, and hydrothermal temperature on the morphologies and electrochromic properties of as-prepared WNRAs were studied thoroughly. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and chronoamperometry techniques were used to characterize the structures and properties of obtained WNRAs. The results demonstrate that the average diameter of the as-prepared WNRAs ranged from 30 to 70 nm. During the decoration of Mo on the WNRAs, the growth density of as-prepared WNRAs decreased and the surfaces became rough. However, the decorated Mo on WNRAs synthesized at 180 °C for 5 h with a Mo/W mole ratio of 1:40 exhibited better electrochromic properties than single WNRAs. They exhibited high optical modulation (61.7%), fast bleaching/coloring response times (3 s/9 s), high coloration efficiency values (73.1 cm2/C), and good cycling stability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.