Ethanol Sensing Properties and First Principles Study of Au Supported on Mesoporous ZnO Derived from Metal Organic Framework ZIF-8

Abstract

It is of great significance to develop ethanol sensors with high sensitivity and low detection temperature. Hence, we prepared Au-supported material on mesoporous ZnO composites derived from a metal-organic framework ZIF-8 for the detection of ethanol gas. The obtained Au/ZnO materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (SEM), field emission transmission electron microscopy (TEM) and nitrogen adsorption and desorption isotherms. The results showed that the Au/ZnO-1.0 sample maintains a three-dimensional (3D) dodecahedron structure with a larger specific surface area (22.79 m2 g−1) and has more oxygen vacancies. Because of the unique ZIF structure, abundant surface defects and the formation of Au-ZnO Schottky junctions, an Au/ZnO-1.0 sensor has a response factor of 37.74 for 100 ppm ethanol at 250 °C, which is about 6 times that of pure ZnO material. In addition, the Au/ZnO-1.0 sensor has good selectivity for ethanol. According to density functional theory (DFT) calculations, the adsorption energy of Au/ZnO for ethanol (−1.813 eV) is significantly greater than that of pure ZnO (−0.217 eV). Furthermore, the adsorption energy for ethanol is greater than that of other gases.

Monitoring Charge Transfer Dynamics of Surface Trapped Holes in ZnO Surface Utilized for Ethanol Oxidation Using Heterodyne Transient Grating Spectroscopic Techniques

“…Zinc oxide (ZnO) has been regarded as one of the best photocatalysts due to its strong chemical stability, simple fabrication method, high charge mobility and large surface area. − These properties also enable us to utilize it for a gas-sensitive sensor, an electron transport layer (ETL) in perovskite solar cell (PSC), a photoelectrode in photoelectrochemical (PEC) cell and so on. ,− …”

Study on the Photocatalytic Properties of Metal–Organic Framework-Derived C-, N-Co-Doped ZnO

“…Zeolite imidazolium skeleton-8 (ZIF-8) is a synthetic MOF characterised by a large specific surface area, diverse structure, adjustable pore size, easy design, and the controllability of pore surface properties. Additionally, the derivatisation of MOFs provides a novel method for fabricating C-, N-co-doped ZnO [21,22]. For example, Zheao Huang et al [23] explored the tunable nitrogen configuration in the sample N-ZnO@NC by controlling the thermal conversion of ZIF-8.…”

In situ assembly of one-dimensional Pt@ZnO nanofibers driven by a ZIF-8 framework for achieving a high-performance acetone sensor

“…18,19 Because of the confinement by the rigid organic ligand framework and improved support–metal interaction, the noble metal NPs within ZIF-8 are restrained from relocating, which would provide the following superiorities: (1) the noble metal NPs preserve the good dispersion within the cavity of ZIF-8 during the synthetic process; (2) the well-dispersed structure is beneficial to reduce the formation of low-resistance channels and guarantees the maximum exposure of the active sites for the gas-sensing process; and (3) this strategy allows for in situ doping of noble metals and increases the number of lattice defects and oxygen vacancies. 20–22…”

“…18,19 Because of the confinement by the rigid organic ligand framework and improved support-metal interaction, the noble metal NPs within ZIF-8 are restrained from relocating, which would provide the following superiorities: (1) the noble metal NPs preserve the good dispersion within the cavity of ZIF-8 during the synthetic process; (2) the well-dispersed structure is beneficial to reduce the formation of low-resistance channels and guarantees the maximum exposure of the active sites for the gas-sensing process; and (3) this strategy allows for in situ doping of noble metals and increases the number of lattice defects and oxygen vacancies. [20][21][22] In recent decades, numerous studies have been performed on sensing materials to enhance gas sensing performance. [23][24][25] Especially, the strategy of employing one-dimensional (1D) nanostructures is extremely beneficial for gas sensors owing to the adequate reaction region between the active sites and the analytes and the favorable electron transport structure.…”