A nano-gas sensor based on Pd-SnO2 composite nanofibers is fabricated by electrospinning technique and calcination procedure. The morphology, structure and composition of the as-prepared nanofibers are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM). Xray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), respectively. The nano-gas sensor shows excellent hydrogen sensing properties such as high sensitivity and extremely fast response-recovery behavior (similar to 9 s) at a lower operation temperature (280 degrees C). The detect ion limit of approximately 4.5 ppm H-2 is demonstrated. The function of adding Pd into the SnO2 nanofibers and the sensing mechanism have also been discussed in this work. (c) 2010 Elsevier B.V. All rights reserved.