Pd-Functionalized SnO₂ Nanofibers Prepared by Shaddock Peels as Bio-Templates for High Gas Sensing Performance toward Butane.

Pd-functionalized one-dimensional (1D) SnO₂ nanostructures were synthesized via a facile hydrothermal method and shaddock peels were used as bio-templates to induce a 1D-fiber-like morphology into the gas sensing materials. The gas-sensing performances of sensors based on different ratios of Pd-functionalized SnO₂ composites were measured. All results indicate that the sensor based on 5 mol % Pd-functionalized SnO₂ composites exhibited significantly enhanced gas-sensing performances toward butane. With regard to pure SnO₂, enhanced levels of gas response and selectivity were observed. With 5 mol % Pd-functionalized SnO₂ composites, detection limits as low as 10 ppm with responses of 1.38 ± 0.26 were attained. Additionally, the sensor exhibited rapid response/recovery times (3.20/6.28 s) at 3000 ppm butane, good repeatability and long-term stability, demonstrating their potential in practical applications. The excellent gas-sensing performances are attributed to the unique one-dimensional morphology and the large internal surface area of sensing materials afforded using bio-templates, which provide more active sites for the reaction between butane molecules and adsorbed oxygen ions. The catalysis and "spillover effect" of Pd nanoparticles also play an important role in the sensing of butane gas as further discussed in the paper.