Atomically Dispersed Au on In₂O₃ Nanosheets for Highly Sensitive and Selective Detection of Formaldehyde

Abstract

As an important industrial chemical, formaldehyde is used in various fields but is harmful to health. Developing a convenient detection device for formaldehyde is significant. Based on atomically dispersed Au on In 2 O 3 nanosheets, a formaldehyde sensor was fabricated in this work. The highly dispersed Au obtained by the ultraviolet (UV) light-assisted reduction method helps improve the sensing performance. A meager loading amount (0.01 wt %) of Au on In 2 O 3 nanosheets exhibits high sensitivity toward ppb-level formaldehyde. Au acts as an electron sink and promotes the oxidation of formaldehyde. Atomically dispersed Au on In 2 O 3 nanosheets decreases the activation energy and increases the number of active sites, which result in a highly efficient conversion of formaldehyde and a marked resistance change of the fabricated sensors. The selective adsorption and oxidation of formaldehyde on single atom Au's uniform sites establish excellent selectivity. Besides, the sensor exhibits short response/recovery time and excellent stability, with promising applications in formaldehyde detection.

Strategies for Improving the Sensing Performance of Semiconductor Gas Sensors for High-Performance Formaldehyde Detection: A Review

“…Xue et al [65] prepared mesoporous Ag/In 2 O 3 composites by calcining Ag in an organic framework (OFs). The experimental results prove that when the load of Ag was 5%, the response value of Ag/In 2 O 3 sensor was five times of that of the single oxide sensor under 210 • C. Gu et al [66] obtained a high performance HCHO sensor on the nano-scale of In 2 O 3 based on atom dispersion by UVassisted reduction. The response to 50 ppm HCHO was 85.67, and LOD attained 1.42 ppb at the optimum operating temperature of 100 • C. Atomic-level dispersion not only increases the homogeneity of dispersion, but also reduces the usage of precious metals.…”

“…times of that of the single oxide sensor under 210 °C . Gu et al [66] obtained a high performance HCHO sensor on the nano-scale of In2O3 based on atom dispersion by UV-assisted reduction. The response to 50 ppm HCHO was 85.67, and LOD attained 1.42 ppb at the optimum operating temperature of 100 °C .…”

Inorganic-Diverse Nanostructured Materials for Volatile Organic Compound Sensing

“…However, the ZnO NShs (adopted from hydrothermal method; Figure 16) were engaged in aqueous phase detection of HCHO with linear regression of 10 nM to 1 mM and a LOD of 210 nM; thus, it cannot be listed as device-based assays [265]. Compared to other HCHO sensory reports, Au atom dispersed In2O3 NShs (developed by light assisted reduction method) were highly fascinated with respect to its sensor reposes (Ra/Rg = 85.67 for 50 ppm at 100 °C; response/recovery time = 25 s/198 s) with an exceptional LOD of 0.00142 ppm [266]. PdAu bimetal decorated SnO2 NShs (synthesized by hydro-solvothermal treatment) were reported for the detection of both acetone and HCHO at 250 °C and 110 °C, respectively, with a LODs down to sub-ppm level [267].…”

“…High resolution SEM and TEM images of nanosheets are dispayed in Figure 16. WO 3 clusters decorated In 2 O 3 NShs (synthesized by impregnating method), SnO 2 NShs, ZnO NShs, Au atom dispersed In 2 O 3 NShs, and PdAu bimetal decorated SnO 2 NShs were exploited in the discrimination of HCHO at various operating temperatures [263][264][265][266][267]. However, the ZnO NShs (adopted from hydrothermal method; Figure 16) were engaged in aqueous phase detection of HCHO with linear regression of 10 nM to 1 mM and a LOD of 210 nM; thus, it cannot be listed as device-based assays [265].…”

On‐Site Detection for Hazardous Materials in Chemical Accidents

“…In addition, a surface plasmon‐enhanced optical sensor was prepared by the deposition of a mixture of semiconductor core‐shell quantum dots, fumed‐silica, and AuNPs on a silica‐sphere array which aimed for the HCHO detection (Figure 3(a)). 77 Based on either atomically dispersed Au on In 2 O 3 nanosheets, 78 or zeolitic imidazolate framework‐8/multiwalled carbon nanotube, 79 and colorimetric visualization using polymeric core–shell nanoparticles, 80 the nanosensor platforms were enhanced sensitivity for HCHO gas detection at room temperature. Hence, these approaches are promising for real‐time HCHO gas monitoring and can also be adapted to apply in many fields as well as HCHO gas sensor systems for indoor safety and industrial processing.…”