Ca2Ge7O16 nanowires grown from CaO and GeO2

Abstract

Single crystalline Ca 2 Ge 7 O 16 nanowires have been synthesized using CaO and GeO 2 as the raw materials. Various factors that affect the formation and size of the Ca 2 Ge 7 O 16 nanowires have been analyzed. The obtained products are characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The results show that the calcium germanate nanowires are composed of orthorhombic Ca 2 Ge 7 O 16 phase with the length and diameter of several dozens of micrometers and about 50 nm, respectively. Hydrothermal temperature plays an important role on the formation and growth of the Ca 2 Ge 7 O 16 nanowires. The formation process of the Ca 2 Ge 7 O 16 nanowires is initially interpreted according to the shape evolution of the products obtained from different growth conditions.

Single crystalline Sr germanate nanowires and their photocatalytic performance for the degradation of methyl blue

“…The flat tips are similar to those of the Ca germanate nanowires, Cd germanate nanowires and Pb germanate nanowires synthesized by a similar hydrothermal process. [24][25][26]31 It is obviously observed that the Sr germanate nanowires are composed of a good single crystalline structure (Fig. 2(d)) which is also similar to that of the nanowires synthesized from a similar hydrothermal process.…”

“…2(d)) which is also similar to that of the nanowires synthesized from a similar hydrothermal process. 1,25,27,31 Fig. 3 shows the FTIR spectrum of the Sr germanate nanowires synthesized at 180 uC for 24 h at 450-4000 cm 21 .…”

“…The hydrothermal method is a facile and efficient method to synthesize 1D nanowires that exhibit promising potential for synthesizing crystalline nanowires at a low cost. 22,23 In our past research, crystalline calcium germanate nanowires, 24,25 cadmium germanate nanowires 26 and copper germanate nanowires 27 have been synthesized via a simple hydrothermal process by adjusting the metal and salt acetate raw materials and they exhibited good optical and electrochemical properties. 28,29 In this paper, single crystalline Sr germanate nanowires with the orthorhombic SrGeO 3 phase have been synthesized via a simple hydrothermal process using Ge dioxide and Sr acetate as the raw materials.…”

The Germanate Anomaly in Alkaline Earth Germanate Glasses

“…Germanate glasses, in general, have advantageous optical properties, including their wider infrared transmission windows, compared to silicates; calcium germanates, specifically, have attracted attention owing to their photoluminescence and ability to be prepared as both crystalline and amorphous nanowires. Doped alkaline earth (Ae) germanate glasses have shown promise for application as fibers for broad-band amplification and laser tuning; doped Ca gallogermanate glasses, , as tunable solid-state laser sources; Ba gallogermanate glasses, as windows in high-energy laser systems; and Sr gallogermanate glasses, as nontoxic fibers for medical laser applications .…”

“…34−37 Schlenz et al 38 used high-energy and anomalous X-ray scattering and electron diffraction to study a single-phase 28.2BaO•71.8GeO 2 glass. Two (unresolved) Gaussian peaks were fitted to the Ge−O correlation, yielding a total n GeO = 3.9 (1), though the ratio of the two fitted peak areas was used to infer a ratio of 6-fold to 4-fold coordinated germanium of 1:3, which itself implies n GeO = 4.5. The discrepancy is due in part to the fitting of Gaussian functions to the radial distribution function extracted by high-energy (100 keV) X-ray total scattering, which neglects the broadening arising from the Xray form factors and the truncation in reciprocal space.…”