Electrochemical acetylene sensor based on Au/MWCNTs

Gold nanoparticles supported on multi-walled carbon nanotubes (Au/MWCNTs) were prepared as electrocatalysts for an electrochemical sensor of acetylene. The catalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical experiments showed that the catalysts exhibited a distinctly higher activity for the acetylene electro-oxidation than Au-NPs and Au/C catalysts. In typical cyclic voltammograms, the onset potential of Au/MWCNTs for the acetylene oxidation is 0.73 V, which is 0.19 V more negative than that of Au-NPs. The acetylene sensor test showed good linear response towards acetylene concentration in a wide range from 10 ppm to 50 ppm with a steady response current for 300 s, good sensitivity of 80 nA/ppm and fast 90% response time (t90) of 25 s to 50 ppm acetylene. All the results indicate a good potential application of this sensor in the detection of acetylene.