In situ laser-assisted decoration of Au nanoparticles on 3D porous graphene for enhanced 2-CEES sensing

Abstract

The fabrication of gas-sensing devices with high sensitivity and low limit of detection (LOD) for monitoring chemical warfare agents and their simulants is of great importance. Metal oxide-based semiconducting nanomaterials and their heterojunctions hold great promise in chemiresistive gas sensing. However, the demands of high working temperature, integration on interdigitated electrodes (IDEs) and requirement of additional heaters impede their popularity. This work demonstrates in situ laser-assisted preparation of Au-decorated laser-induced graphene (LIG/Au) hetero-material as a flexible and effective near-room-temperature 2-chloroethyl ethyl sulfide (2-CEES) sensor. The structure of the sensor was simplified via omitting the IDE and an additional heating module. After optimizing the concentration of the HAuCl₄ precursor solution and power of secondary scribing, the LIG/Au-0.1 M gas sensor exhibited an enhanced response of 7.85‰ to 1.0 ppm 2-CEES, which is twice that of pure LIG. Furthermore, its LOD was as low as 5.8 ppb. The sensing mechanism analysis revealed that the decoration of Au nanoparticles enriched the active sites of LIG/Au-0.1 M and provided catalytic and sensitization effects. The present study not only provides an appealing 2-CEES gas sensor but also demonstrates an effective method for large-scale fabrication of other high-performance sensing devices.