Improvement of Ethanol Gas-Sensing Responses of ZnO–WO₃ Composite Nanorods through Annealing Induced Local Phase Transformation

• Main Authors: Yuan-Chang Liang, Che-Wei Chang
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: Nanomaterials
• Subjects: sputtering; composite nanorods; phase transformation; annealing
• Online Access: https://www.mdpi.com/2079-4991/9/5/669

In this study, ZnO−WO₃ composite nanorods were synthesized through a combination of hydrothermal growth and sputtering method. The structural analysis results revealed that the as-synthesized composite nanorods had a homogeneous coverage of WO₃ crystallite layer. Moreover, the ZnO−WO₃ composite nanorods were in a good crystallinity. Further post-annealed the composite nanorods in a hydrogen-containing atmosphere at 400 °C induced the local phase transformation between the ZnO and WO₃. The ZnO−WO₃ composite nanorods after annealing engendered the coexistence of ZnWO₄ and WO₃ phase in the shell layer which increased the potential barrier number at the interfacial contact region with ZnO. This further enhanced the ethanol gas-sensing response of the pristine ZnO−WO₃ composite nanorods. The experimental results herein demonstrated a proper thermal annealing procedure of the binary composite nanorods is a promising approach to modulate the gas-sensing behavior the binary oxide composite nanorods.