CO2 and CO gas sensing properties of nanostructured BiOCl ribbons doped with gold nanoparticles

Nanostructured ribbons of bismuth oxychloride (BiOCl), doped with gold nanoparticles (AuNPs), were obtained by a surfactant-assisted method at 600 °C. AuNPs were synthesized using pluronic P103 in aqueous media. The CO2 and CO gas sensing properties of BiOCl-AuNPs thick films were characterized by alternate current (AC) and direct current (DC). These gases, having a concentration of 100 ppm, were detected from 200 °C (100 kHz); however, the best results were obtained at 300 °C. The quantitative detection of CO2 and CO was demonstrated by increasing the concentration of the gases, from 100 ppm to 400 ppm; which produced a proportional increase of the impedance. The catalytic CO spillover oxidation played a key role in the detection of this gas, because AuNPs with sizes between 8 nm and 30 nm were used.