A PdPt decorated SnO -rGO nanohybrid for high-performance resistive sensing of methane

SnO2, SnO2-PdPt, and PdPt decorated SnO2-rGO (SnO2-rGO-PdPt) samples were presented to use in resistive sensing of methane. A hydrothermal method was used to synthesize SnO2 and SnO2-rGO and these were then easily doped with PdPt catalyst by in situ reductions of their metallic salts. The responses to gaseous methane at levels between 500 and 10,000 ppm were measured in the temperature range of 50–250 °C. Results demonstrated that the dopants can increase the response of SnO2 sensor toward 1000 ppm methane from 12.5% (for bare SnO2) to 32.7% (for SnO2-PdPt) and 69.5% (for SnO2-rGO-PdPt) at 150 °C. In addition, the optimum operating temperature was reduced from 300 °C (for SnO2) to 150 °C (for SnO2-rGO-PdPt). The catalyst also improved the stability during continuous cycles. The response and recovery times of SnO2-rGO-PdPt sensor at 150 °C and flow rate of 160 sccm of 1000 ppm methane, were 50 s and 4.5 min respectively. A sensing mechanism is suggested in details.