Achieving Molecular-Level Selective Detection of Volatile Organic Compounds through a Strong Coupling Effect of Ultrathin Nanosheets and Au Nanoparticles

Abstract

The high density of surface active sites, high efficiency of interfacial carrier transport, and molecular diffusion path determine the efficiency of the electrochemical sensors. The ultrathin structures have atomic-level thickness, carrier migration and heat diffusion are limited in the two-dimensional plane, resulting in excellent conductivity and high carrier concentration. A one-step chemical method is applied to synthesize defect-rich Au-SnO 2 in an ultrathin nanosheet form (thickness of 2−3 nm). The strong interaction between Au and SnO 2 via the Au−O−Sn bonding and the catalytic effect of Au can prolong the service life via decreasing the optimal operating temperature (55 °C) and promote the Au-SnO 2 sensor to exclusively detect formaldehyde at the ppb level (300 ppb). The experimental findings along with theoretical study reveal that Au nanoparticles have a different effect on the competitive adsorption and chemical reaction over the surface of the Au−SnO 2 with formaldehyde and other interfering VOC gases, such as methanol, ethanol, and acetone. This study provides mechanistic insights into the correlation between operating temperature and the performance of the Au−SnO 2 chemiresistive sensor. This work allows the development of highly efficient and stable electrochemical sensors to detect VOC gases at room temperature in the future.

Programmable and Modularized Gas Sensor Integrated by 3D Printing

“…The comprehensive development of gas detection and analysis systems is important for monitoring atmospheric conditions, safeguarding human health, and ensuring the optimal functioning of electronic instruments. To quantify these imperceptible environmental variables, various gas sensors predicated on distinct detection principles have been extensively researched and employed. − These include electrically transduced gas sensors, acoustic gas sensors, optical gas sensors, thermal gas sensors, electrochemical gas sensors, and gas chromatography, each tailored for specific application scenarios leveraging their unique attributes. − The performances of the gas sensors are principally gauged by the key indicators including response, sensitivity, selectivity, limit of detection, response/recovery time, and stability. , These parameters evaluate the output signal intensity, the proportional response to gas concentration, the specificity for target gas detection, the minimum detectable concentration of the target gas, the time span for attaining a stable output or baseline reading after exposure to or withdrawal from the target gas, and long-term operation capability, respectively. They are profoundly influenced by the configuration of their constituent components, especially from the active material, chamber, and channels with special aerodynamic performance requirements. , Fortunately, these elements are amenable to optimization through geometric modification and can be precisely and efficiently fabricated using 3D printing technologies.…”