Fabrication of Nanosized Island-Like CdO Crystallites-Decorated TiO₂ Rod Nanocomposites via a Combinational Methodology and Their Low-Concentration NO₂ Gas-Sensing Behavior

Yuan-Chang Liang; Nian-Cih Xu; Chein-Chung Wang; Da-Hua Wei

doi:10.3390/ma10070778

Fabrication of Nanosized Island-Like CdO Crystallites-Decorated TiO₂ Rod Nanocomposites via a Combinational Methodology and Their Low-Concentration NO₂ Gas-Sensing Behavior

Materials (Basel). 2017 Jul 10;10(7):778. doi: 10.3390/ma10070778.

Authors

Yuan-Chang Liang¹, Nian-Cih Xu², Chein-Chung Wang³, Da-Hua Wei⁴

Affiliations

¹ Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan. yuanvictory@gmail.com.
² Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan. sad821008@gmail.com.
³ Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan. abc2589tw@gmail.com.
⁴ Graduate Institute of Manufacturing Technology and Department of Mechanical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan. dhwei@ntut.edu.tw.

Abstract

TiO₂-CdO composite rods were synthesized through a hydrothermal method and sputtering thin-film deposition. The hydrothermally derived TiO₂ 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 TiO₂ rods formed a discontinuous shell layer comprising many island-like CdO crystallites. The TiO₂-CdO composite rods were highly crystalline, and their surfaces were rugged. A comparison of the NO₂ gas-sensing properties of the CdO thin film, TiO₂ rods, and TiO₂-CdO composite rods revealed that the composite rods exhibited superior gas-sensing responses to NO₂ gas than did the CdO thin film and TiO₂ rods, which can be attributed to the microstructural differences and the formation of heterojunctions between the TiO₂ core and CdO crystallites.

Keywords: microstructure; rod nanocomposite; sensing performance; sputtering.