Superior sensitivity towards H-2 gas was successfully achieved with Pt-decorated GaN nanowires (NWs) gas sensor. GaN NWs were fabricated via chemical vapor deposition (CVD) route. Morphology (field emission scanning electron microscopy and transmission electron microscopy) and crystal structure (high resolution X-ray diffraction) characterizations of the as-synthesized nanostructures demonstrated the formation of GaN NWs having a wurtzite structure, zigzaged shape and an average diameter of 30166 nm. The Pt-decorated GaN NWs sensor shows a high response of 250-2650% upon exposure to H2 gas concentration from 7 to 1000 ppm respectively at room temperature (RI), and then increases to about 650-4100% when increasing the operating temperature up to 75 degrees C. The gas-sensing measurements indicated that the Pt-decorated GaN NWs based sensor exhibited efficient detection of H-2 at low concentration with excellent sensitivity, repeatability, and free hysteresis phenomena over a period of time of 100 min. The large surface-to-volume ratio of GaN NWs and the catalytic activity of Pt metal are the most influential factors leading to the enhancement of H-2 gas-sensing performances through the improvement of the interaction between the target molecules (H-2) and the sensing NWs surface. The attractive low-cost, low power consumption and high-performance of the resultant decorated GaN NWs gas sensor assure their uppermost potential for H-2 gas sensor working at low operating temperature. (C) 2015 Elsevier Inc. All rights reserved.