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.