Synthesis of tin oxide (SnO & SnO2) micro/nanostructures with novel distribution characteristic and superior photocatalytic performance

Abstract

SnO micro/nanostructures with novel distribution characteristic of concentric annulus were successfully synthesized by electrochemical anodization of tin foils in sodium hydroxide electrolyte. The SnO structures near the central fracture region were uniform and well-defined octahedron-like. The SnO structures away from the fracture region gathered together and presented petal-like and flower-like patterns. The effects of anodizing parameters and annealing temperatures on the structure features of tin oxide micro/nanostructures were systematically investigated. We found that as-anodized SnO micro/nanostructures can be transformed to tetragonal phase SnO2 micro/nanostructures by a thermal annealing process, which still maintained its original structure features as well as distribution characteristic. The optical property and photocatalytic performance of the annealed samples were also analyzed. The high photocatalytic property of the sample annealed at 400°C was attributed to the strong light absorption and efficient interfacial charge separation. Additionally, a synthesis mechanism was discussed to illustrate the evolution process of anodized SnO micro/nanostructures with the distribution characteristic of concentric annulus.