Development of the Morphology and the Band Gap Energy of Co–Si Nanofibers by Inserting Zirconium and Titanium with Dual Anions Intercalation Process

Abstract

The plate-like structure is the most familiar morphology for conventional layered double hydroxides (LDHs) in case their structures consist of divalent and trivalent cations in their layers. In this study, nanofibers and nanoneedles of Co–Si LDHs were prepared for the first time. By the inclusion of zirconium inside the nanolayers of LDH structures, their plates were formed and transformed to nanofibers. These nanofibers were modified by the insertion of titanium to build again plate-like morphology for the LDH structure. This morphology controlling was studied and explained by a dual anions intercalation process. The optical properties of Co–Si LDHs indicated that the incorporation of zirconium within their nanolayers decreased the band gap energy from 4.4 eV to 2.9 eV. Following the same behavior, the insertion of titanium besides zirconium within the nanolayers of Co–Si LDHs caused a further reduction in the band gap energy, which became 2.85 eV. Although there is no data for the optical properties of Co–Si LDHs in the literature, it is interesting to observe the low band gap energy for Co–Si LDHs to become more suitable for optical applications. These results concluded that the reduction of the band gap energy and the formation of nanofibers introduce new optical materials for developing and designing optical nanodevices.

Enhancement of the Supercapacitive Performance of Cobalt-tin-cyanate Layered Structures through Conversion from 2D Materials to 1D Nanofibers

“…cations [26]. Figure 2d confirms this speculation through displaying the conversion of Sn/Co plates to nanofibers.…”

“…In addition, individual fibers with diameters of 50 nm are displayed in Figure 2c. However, the plate morphology is the most famous morphology for the natural samples of layered double hydroxides, which consist of di-and trivalent cations [26]. Figure 2d confirms this speculation through displaying the conversion of Sn/Co plates to nanofibers.…”

“…This phenomenon is in agreement with the results of Xu et al [34] that indicated the outcome of the existence of nitrate ions on the bands of LDH. The shoulder peaks recorded at 2925 cm −1 indicate the stretching OH bonds that are due to the interlayer water molecules and/or produced from the hydrogen bonds formed with cyanate ions [15,26,35,36]. The peak at 1617 cm −1 was due to the bending band of the water molecules [37].…”

Development of Ti/Ni Nanolayered Structures to Be a New Candidate for Energy Storage Applications

“…The insertion of cyanate and isocyanate anions into the Ni-Ti LDHs structure was verified by appearance of two bands. These two bands overlapped and centered at 2217 cm −1 [29][30][31][32]. As can be noted in Figure 4, traces of carbonate anions were also detected by a weak peak at 1459 cm −1 [28].…”