ScienceDirect.com - Materials Research Bulletin - Facile synthesis of self-assembled SnO nano-square sheets and hydrogen absorption characteristics:
Stannous oxide is an important functional material which contributes to a wide range of applications in energy storage and optoelectronic devices. In the present study, the single crystalline self-assembled stannous oxide (SnO) 2D nano-square sheets have been synthesized with template-free hydrothermal growth method. The morphology, composition and structure were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Raman spectroscopy, respectively. FESEM results have illustrated that the size of self-assembled 3D hierarchical polygon-shape structure of SnO is in the range of 8–12 μm and the average size of the nano-square sheets is about 100 nm. X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns have revealed that the prepared SnO nano-square sheets exist in single-crystalline nature. Two Raman modes A1g = 211 cm−1 and B1g = 113 cm−1 were observed by Raman spectroscopy, which is consistent with nano tetragonal phase SnO. Furthermore, the chemical valence of Sn and relative atomic composition of as-prepared SnO have been confirmed by X-ray photoelectron spectroscopy (XPS). Ultraviolet–visible–near infrared spectrophotometry was used to study the transmittance behavior of SnO nano-structures and direct optical band gap of 3.16 eV was acquired by using Davis–Mott model. The first ever study on hydrogen absorption characteristics of SnO nano-square sheets performed at 373 K shows good absorption capacity of 1.194 wt.%.
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Tuesday, September 25, 2012
A single-source precursor route to Ag/SnO2 heterogeneous nanomaterials and its photo-catalysis in degradation of Conco Red
ScienceDirect.com - Materials Research Bulletin - A single-source precursor route to Ag/SnO2 heterogeneous nanomaterials and its photo-catalysis in degradation of Conco Red:
Ag/SnO2 heterogeneous material was obtained via directly decomposing single-source precursor Ag2SnO3 at temperature of 400 °C, owing to the in situ growth from the decomposition. This kind of heterogeneous structure was helpful to improve the photocatalysis efficiency. When Ag/SnO2 heterogeneous material was employed as photocatalysts in the degradation of Conco Red, its catalytic efficiency is 3-fold that of the mixture of Ag and SnO2 powders.
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Ag/SnO2 heterogeneous material was obtained via directly decomposing single-source precursor Ag2SnO3 at temperature of 400 °C, owing to the in situ growth from the decomposition. This kind of heterogeneous structure was helpful to improve the photocatalysis efficiency. When Ag/SnO2 heterogeneous material was employed as photocatalysts in the degradation of Conco Red, its catalytic efficiency is 3-fold that of the mixture of Ag and SnO2 powders.
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High-yield synthesis of SnO2 nanobelts by water-assisted chemical vapor deposition for sensor applications
ScienceDirect.com - Materials Research Bulletin - High-yield synthesis of SnO2 nanobelts by water-assisted chemical vapor deposition for sensor applications:
Well-crystallized one-dimensional (1D) SnO2 nanobelts were in situ prepared using a simple water-assisted chemical vapor deposition (CVD) method. The small Sn particles with Au-modifications were used as source materials instead of big size Sn grains to ensure the high yield of SnO2 belts. The Au layer was modified on the small Sn particles by treating Sn powders in HAuCl4 solution combined with the UV irradiation. The as-prepared SnO2 nanobelts were characterized by SEM, HRTEM, XRD, EDS and XPS. These results indicate that the growth temperature plays an important role in controlling the length-to-width ratio of nanobelts. The length-to-width ratio decreases with the growth temperature from 850 °C to 1000 °C. The nanobelts prepared at 850 °C shows a single-crystalline tetragonal rutile phase with a high length-to-width ratio (approximately tens of microns in length and 40–70 nm in width). However, below 850 °C, nanobelts cannot be formed. The as-prepared nanobelts exhibited excellent sensing properties compared with SnO2 nanoparticles and high sensing selectivity towards NO2. The high sensing selectivity to NO2 is attributed to the oxygen vacancies presenting in the as-prepared nanobelts.
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Well-crystallized one-dimensional (1D) SnO2 nanobelts were in situ prepared using a simple water-assisted chemical vapor deposition (CVD) method. The small Sn particles with Au-modifications were used as source materials instead of big size Sn grains to ensure the high yield of SnO2 belts. The Au layer was modified on the small Sn particles by treating Sn powders in HAuCl4 solution combined with the UV irradiation. The as-prepared SnO2 nanobelts were characterized by SEM, HRTEM, XRD, EDS and XPS. These results indicate that the growth temperature plays an important role in controlling the length-to-width ratio of nanobelts. The length-to-width ratio decreases with the growth temperature from 850 °C to 1000 °C. The nanobelts prepared at 850 °C shows a single-crystalline tetragonal rutile phase with a high length-to-width ratio (approximately tens of microns in length and 40–70 nm in width). However, below 850 °C, nanobelts cannot be formed. The as-prepared nanobelts exhibited excellent sensing properties compared with SnO2 nanoparticles and high sensing selectivity towards NO2. The high sensing selectivity to NO2 is attributed to the oxygen vacancies presenting in the as-prepared nanobelts.
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