High-yield synthesis of SnO2 nanobelts by water-assisted chemical vapor deposition for sensor applications

Well-crystallized one-dimensional (1D) SnO 2 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 SnO 2 belts. The Au layer was modified on the small Sn particles by treating Sn powders in HAuCl 4 solution combined with the UV irradiation. The as-prepared SnO 2 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 SnO 2 nanoparticles and high sensing selectivity towards NO 2 . The high sensing selectivity to NO 2 is attributed to the oxygen vacancies presenting in the as-prepared nanobelts.