Binder-free CuO nanoneedle arrays based tube-type sensor for H2S gas sensing

Abstract CuO nanoneedle arrays were directly prepared on the commercial ceramic tubes by magnetron sputtering and subsequent wet chemical etching and annealing. This brand-new fabrication of the tube-type gas sensor retains the high specific surface area of nanoneedle and avoids using binders that are generally used for coating gas-sensitive materials on the surface of the ceramic tube. The as-fabricated binder-free CuO nanoneedle arrays sensor exhibits a decent response of 76.50 % to 10 ppm H2S at a low temperature of 150 ℃. The response decreases to 20.27 % as the relative humidity increases from 40 % to 80 %. Moreover, the sensor shows good selectivity, reproducibility, and long-term stability to a low concentration of 10 ppm H2S. This superior sensing performance can be attributed to the abundant surface reactive adsorption sites provided by CuO nanoneedle arrays and the sensitization effect of p-p nano-homojunctions that arose from the interlaced CuO nanoneedles.