Nanoporous Gold as a VOC Sensor, Based on Nanoscale Electrical Phenomena and Convolutional Neural Networks

Abstract

Volatile organic compounds (VOCs) are prevalent in daily life, from the lab environment to industrial applications, providing tremendous functionality but also posing significant health risk. Moreover, individual VOCs have individual risks associated with them, making classification and sensing of a broad range of VOCs important. This work details the application of electrochemically dealloyed nanoporous gold (NPG) as a VOC sensor through measurements of the complex electrical frequency response of NPG. By leveraging the effects of adsorption and capillary condensation on the electrical properties of NPG itself, classification and regression is possible. Due to the complex nonlinearities, classification and regression are done through the use of a convolutional neural network. This work also establishes key strategies for improving the performance of NPG, both in sensitivity and selectivity. This is achieved by tuning the electrochemical dealloying process through manipulations of the starting alloy and through functionalization with 1-dodecanethiol.

Selective Toluene Detection with Mo2CTx MXene at Room Temperature

“…Researchers have been adopting various transducers and classification models to detect VOCs. [11][12] Toluene is regarded as one of the most hazardous VOC pollutants in the air and a major threat to human health, 13 with even low levels of inhalation causing dizziness, confusion, and color-vision issues. 14 In addition, due to the carcinogenic nature of nitrated toluene, long-term exposure could lead to respiratory cancer.…”

Recent Advancements in the Fabrication of Functional Nanoporous Materials and Their Biomedical Applications

“…Nanoporous materials are categorized as an important class of nanostructured material that possess unique surface and structural characteristics, including high surface area, tunable pore sizes, tunable pore geometries, as well as surface topographies with porous architectures. These unique characteristics of nanoporous materials underline their applications in various fields, such as ion-exchange [ 1 ], separation [ 2 ], catalysis [ 3 ], sensors [ 4 ], water purification [ 5 ], CO 2 capture and storage [ 6 ], renewable energy [ 7 , 8 ], targeted drug delivery [ 9 ], tissue engineering [ 10 ], and implants [ 11 ]. For example, the presence of highly active low-coordinated atoms (i.e., atoms with lower numbers of bonds such as atoms on surfaces, steps, and kinks) on interconnected curved backbones of nanoporous structures make them suitable for catalytic applications.…”

Probing the Surface Chemistry of Nanoporous Gold via Electrochemical Characterization and Atom Probe Tomography

“…Nanoporous gold (NPG) derived from selective electrolytic dissolution of Ag from Ag–Au(-Pt) alloys [ 1 , 2 ] has shown promising results in terms of catalysis, sensing, bioanalytical and biomedical applications [ 3 , 4 , 5 , 6 , 7 ]. Gaining insight into the surface composition of metallic nanoporous materials could not only enhance the understanding of the underlying mechanisms of nanoporosity evolution and catalysis, but would be crucial in biosensing applications, in particular, in vivo sensors.…”