Response of rGO and Pd-Decorated rGO to Carbon Monoxide Gas

Reduced graphene oxide (rGO) in combination with palladium (Pd) thin film for the detection of hydrogen (H 2 ) has been widely reported; Pd-decorated rGO for carbon monoxide (CO) gas sensing is rarely discussed. This study reveals palladium nanoparticle-decorated rGO (rGO-Pd) detects CO gas easily for a wide range of temperatures (RT–150°C). The study also shows that the device detects CO with detection limit of 50 parts per million (ppm). Percentage response (%R) of pure rGO- and rGO-Pd-based sensors increase with both concentration and operating temperature increase. CO sensing of rGO also improves when decorated with Pd nanoparticles. Further, the increase in the %R in rGO-Pd is because of the synergistic electron exchange activity of rGO and Pd. New mechanistic insight into the dependence of sensing performance of rGO and rGO-Pd on pre-adsorbed oxygen species and baseline resistance drift at a particular temperature is proposed. The detailed analysis of the variation in adsorbed oxygen and number of electrons exchanged during CO molecule adsorption at different temperatures is discussed. Graphical Abstract