Great enhancement of CH4 sensitivity of SnO2 based nanofibers by heterogeneous sensitization and catalytic effect

- Pt-SnO2 nanofibers were synthesized by electrospinning, which were comprised of strings of tiny SnO2 nanoparticles decorated with Pt and PtO nanoparticles, resulting in the formation of PtO/SnO2 heterojunction and high porosity.
- The 20 mol% Pt-SnO2 NFs showed an obvious response of 1.11 to 1 ppm CH4 at 350 °C and it could detect 600-10,000 ppm CH4 even at a low temperature of 100 °C.
- The CH4 sensing mechanisms of Pt-SnO2 NFs were proposed in detail by PtO/SnO2 heterogeneous sensitization and Pt catalytic effect.

In this study, unloaded and Pt-loaded SnO2 nanofibers (NFs) with 100-150 nm diameters were synthesized by a simple electrospinning technology and then calcined at 600 °C in air. It was observed that the Pt-SnO2 NFs were comprised of strings of tiny SnO2 nanoparticles decorated with Pt and PtO nanoparticles, resulting in the formation of PtO/SnO2 heterojunction and high porosity. And then, we studied the methane (CH4) sensing performance of the sensors fabricated from these NFs and found that 20 mol% Pt-SnO2 NFs exhibited excellent CH4 sensing properties over a temperature range of 100-350 °C, for example, the 20 mol% Pt-SnO2 NFs showed an obvious response of 1.11-1 ppm CH4 at 350 °C, which was 2 orders of magnitude lower than the minimum detection limit of the current SnO2 based CH4 sensors. The great enhancement of the CH4 sensing properties of Pt-SnO2 NFs can be understood by the PtO/SnO2 heterogeneous sensitization and Pt catalytic effect. Our findings present a novel strategy for the application of SnO2 based NFs in highly effective CH4 detection.

259Pt-loaded SnO2 nanofibers which consist of strings of SnO2 nanoparticles decorated with Pt and PtO nanoparticles were successfully synthesized by electrospinning and exhibited highly enhanced sensitivity to CH4 gas.