Functionalized gold-nanoparticles directly grown on graphene-oxide sheets to form porous-stacked sensing material for micro-gravimetric gas sensing

With oleyamine as solvent and reduce agent, Au nanoparticles (AuNPs) are in situ grown on graphene oxide (GO) sheets. Thereafter, porous-layered stack of AuNPs-rGO nanosheets is formed by a gas-phase chemical-reduction step. After the AuNPs modified with 11-mercaptoundecanoic acid (11-MUA) to graft - COOH sensing groups to amine, the functionalized AuNPs-rGO porous-stacked nanosheets are loaded onto a gravimetric resonant microcantilever as mass sensing material. The rGO sheets serve as multi-layer nanoshelves to support and carry the functionalized AuNPs for gas adsorbing/sensing, while the AuNPs serve as nano-spacer between the rGO sheets to provide high surface-area for gas-molecules accessing. Attributed to the novel sensing material, the cantilever sensor experimentally performs very rapid response to ppm-level trimethylamine (TMA) vapor. Experimentally compared with the hydrophilic AuNPs-GO, the highly hydrophobic property of AuNPs-rGO shows much improved suppression to the noise from environmental humidity change. Featuring rapid response, high sensitivity and good resist against interference from environmental moisture, the novel sensing nano-material is promising in various chemical vapor detection applications.