Au-decorated porous structure graphene with enhanced sensing performance for low-concentration NO₂ detection

A recent progress in new emerging two-dimensional (2D) materials has provided promising opportunity for gas sensing in ultra-low detectable concentration. In this work, we have demonstrated a flexible NO₂ gas sensor with porous structure graphene on polyethylene terephthalate substrates operating at room temperature. The gas sensor exhibited good performance with response of 1.2% and a fast response time within 30 s after exposure to 50 × 10⁻⁹ NO₂ gas. As porous structure of graphene increased the surface area, the sensor showed high sensitivity of ppb level for NO₂ detection. Au nanoparticles were decorated on the surface of the porous structure graphene skeleton, resulting in an incensement of response compared with pristine graphene. Au nanoparticles-decorated graphene exhibits not only better sensitivity (1.5–1.6 times larger than pristine graphene) for NO₂ gas detection, but also fast response. The sensor was found to be robust and sensitive under the cycling bending test, which could also be ascribed to the merits of graphene. This porous structure graphene-based gas sensor is expected to enable a simple and inexpensive flexible gas sensing platform.