Controllable Synthesis of ZnO Nanoflakes with Exposed (101̅0) for Enhanced Gas Sensing Performance

• Published in: Journal of physical chemistry. C 2013-06, Vol.117 (25), p.13153-13162
• Main Authors: Kaneti, Yusuf V, Yue, Jeffrey, Jiang, Xuchuan, Yu, Aibing
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; General equipment and techniques; Growth from solutions; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Materials science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp404329q

This study reports a facile and efficient one-step hydrothermal method for the synthesis of zinc oxide (ZnO) nanoflakes with exposed ZnO(101̅0) surfaces. The as-prepared nanoflakes exhibit excellent sensitivity, selectivity, and stability toward volatile n-butanol gas at the optimized operating temperature of 330 °C. The gas-sensing results further indicate that the chemisorbed oxygen species on the surfaces of the ZnO nanoflakes are dominated by O2– rather than O– ions at 330 °C. The molecular dynamics (MD) method was also employed to understand the underlying fundamentals through simulating the adsorption of different gas molecules onto various ZnO crystal surfaces, such as (101̅0), (112̅0), and (0001). The simulation results confirm the enhancing effect of the exposed (101̅0) surfaces toward n-butanol gas molecules because of their lower diffusion coefficient on (101̅0) compared to those on (112̅0) and (0001) surfaces. The findings will provide new physical insights into the adsorption behaviors of volatile reducing gases on various ZnO surfaces under different temperature and humidity conditions and will be useful for the design and construction of gas-sensing materials with specifically exposed surfaces.