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

Ionic liquid-assisted synthesis of In2O3 nanoparticles for ultra-fast detection of unsymmetrical dimethylhydrazine

Due to the unique physiochemical properties of ionic liquids, they are extensively used as agent or solvent in the synthesis process of nanomaterials. The tailored growth process of functional nanomaterials might result in performance modification for them. In this work, In2O3 nanoparticles were prepared via the hydrothermal method and subsequent calcination (400 °C, 500 °C, 600 °C and 700 °C). An ionic liquid (1-hexadecyl-3-methylimidazolium chloride, [C16Mim] Cl) was introduced in the hydrothermal process. After calcination, trace of [C16Mim] Cl inclusion in In2O3 was pyrolyzed with Cl residue (Cl-In2O3). In compare with control sample synthesized without [C16Mim] Cl (pure In2O3), In2O3-600 (Cl-In2O3 calcined at 600 °C) exhibited an excellent UDMH sensing performance at 225 °C. The fabricated sensor achieved a high response value (71.0 ± 2.1 to 100 ppm), rapid response time (2 s), good selectivity and a low theoretical limit of detection (1.72 ppb) to UDMH gas. Various characterizations, in regard to oxygen vacancy, surface texture structure, energy band structure and surface acidity, were utilized to analyze the cause for enhanced performance. The ionic liquid inclusion increases the contents of adsorbed oxygen species and improves the adsorption capacity to UDMH gas. This work indicates that the synthesized In2O3 nanoparticles could be the potential candidates for rapid UDMH detection in some specific application scenarios.

Programmable and Modularized Gas Sensor Integrated by 3D Printing

The rapid advancement of intelligent manufacturing technology has enabled electronic equipment to achieve synergistic design and programmable optimization through computer-aided engineering. Three-dimensional (3D) printing, with the unique characteristics of near-net-shape forming and mold-free fabrication, serves as an effective medium for the materialization of digital designs into usable devices. This methodology is particularly applicable to gas sensors, where performance can be collaboratively optimized by the tailored design of each internal module including composition, microstructure, and architecture. Meanwhile, diverse 3D printing technologies can realize modularized fabrication according to the application requirements. The integration of artificial intelligence software systems further facilitates the output of precise and dependable signals. Simultaneously, the self-learning capabilities of the system also promote programmable optimization for the hardware, fostering continuous improvement of gas sensors for dynamic environments. This review investigates the latest studies on 3D-printed gas sensor devices and relevant components, elucidating the technical features and advantages of different 3D printing processes. A general testing framework for the performance evaluation of customized gas sensors is proposed. Additionally, it highlights the superiority and challenges of programmable and modularized gas sensors, providing a comprehensive reference for material adjustments, structure design, and process modifications for advanced gas sensor devices.