Synthesis of single-phase Au nanorods in an anodic aluminum oxide template with an optimized process for a highly sensitive and non-enzyme methyl mercaptan gas detector

Abstract

Single-phase Au nanorods were synthesized using an anodic alumina oxide (AAO) template for methyl mercaptan (CH3SH) gas detection. The Au nanorods were fabricated by pulse electrodeposition on a H2O2 modified template. A Au precursor solution was modified with dimethyl sulfoxide to improve the synthesis of Au nanorods. The deposition parameters of the duty cycle were modulated in multiple groups to produce high-quality Au nanorods. Scanning electron microscopy images illustrated the high regularity of the Au nanorods. X-ray diffraction and transmission electron microscopy images revealed the high composition of the (111) lattice interface. A Au nanorod gas sensor was fabricated after removal of the AAO template. The sensor utilized the self-assembled monolayer property between Au and CH3SH to alter the conductivity of the Au nanorod sensing layer. The sensor exhibited higher sensitivity and selectivity to CH3SH than to N2 and H2S. The sensor had a 0.88% current response under a 0.5 ppm concentration of CH3SH, which increased to 7.82% under 4 ppm CH3SH. The Au nanorods possessed a response 13 times higher than that of a Au thin-film structure.