Fabrication of Nanosized Island-Like CdO Crystallites-Decorated TiO 2 Rod Nanocomposites via a Combinational Methodology and Their Low-Concentration NO 2 Gas-Sensing Behavior

摘要

TiO 2 –CdO composite rods were synthesized through a hydrothermal method and sputtering thin-film deposition. The hydrothermally derived TiO 2 rods exhibited a rectangular cross-sectional crystal feature with a smooth surface, and the as-synthesized CdO thin film exhibited a rounded granular surface feature. Structural analyses revealed that the CdO thin film sputtered onto the surfaces of the TiO 2 rods formed a discontinuous shell layer comprising many island-like CdO crystallites. The TiO 2 –CdO composite rods were highly crystalline, and their surfaces were rugged. A comparison of the NO 2 gas-sensing properties of the CdO thin film, TiO 2 rods, and TiO 2 –CdO composite rods revealed that the composite rods exhibited superior gas-sensing responses to NO 2 gas than did the CdO thin film and TiO 2 rods, which can be attributed to the microstructural differences and the formation of heterojunctions between the TiO 2 core and CdO crystallites.