Mesoporous Co3O4 nanoneedle arrays for high-performance gas sensor

Co3O4 arrays were successfully fabricated via a facile two-step approach, including the formation of needle-shaped Co(CO3)(0.5)(OH) 0.11H(2)O followed by thermal conversion to mesoporous Co3O4. The Co3O4 nanoneedle arrays exhibit mesoporosity and quasi-single-crystalline structure, and can directlyserve as gas sensors without the conventional film formation process, owing to the directly growth on thesubstrates and good ohmic contact with the electrodes. The Co(3)O(4)nanoneedle arrays-based gas sensorshowed high performance in ethanol detection. The highest sensitivity reached similar to 89.6 for 100 ppm ethanolvapor and the optimal working temperature was as low as 130 degrees C. The high performance attributes tothe unique structure of nanoneedle arrays with a variety of favorable features. More attractively, we findthe special exposed crystal planes of Co(3)O(4)affect the gas-sensing properties significantly. (C) 2014 Elsevier B. V. All rights reserved.